Answer:
2 8 5
2 8
2 8, 6
2 8 2
2 8 3
2 7
Explanation:
This is your question :
Write the electron arrangement for each of the following atoms:(Example sodium is 2,8,1)
a. phosphorus
b. neon
c. sulfur
d. magnesium
e. aluminum
f. fluorine
Phosphorus is an element in period 3. phosphorus has an atomic number of 15 and it contains 15 electrons. The electron arrangement can be computed as follow ;
2 8 5
This means is has 2 electrons at the first energy level, 8 electron at the second energy level and 5 electron at the third energy level. Base on it configuration phosphorus requires 3 electrons to fulfill it octet rule .
Neon is grouped as a noble gas or inert gas because of it less reactive nature . The atomic number of Neon is 10. The electron arrangement can be computed as follows;
2 8
This means it has 2 electrons on the first energy level and 8 electrons on the second energy level. Neon is in period 2 on the periodic table. Neon electron configuration shows it has fulfilled it octet rule, this is why it rarely goes into a reaction with other elements.
Sulfur
Sulfur has an atomic number of 16 . The electronic configuration is as follows ;
2 8, 6
Sulfur is in period 3 base on it configuration . it possess three energy level with 2 electrons at the first energy level , 8 electrons at the second energy level and 6 at the third energy level.
Magnesium
Magnesium has an atomic number of 12 . Magnesium is in period 3 in the periodic table and are also known as the alkali earth metals. The electronic configuration is as follows ;
2 8 2
The three energy level has 2 electrons, 8 electrons and finally 2 electrons. Magnesium is reactive.
Aluminium
Aluminium has an atomic number of 13 . Aluminium is in period 3 . The electronic configuration is as follows;
2 8 3
The three energy level has 2 electrons, 8 electrons and 3 electrons each .
Florine
Florine has an atomic number of 9. Florine is in period 2 on the periodic table. The electronic configurations is as follows ;
2 7
The two energy level has 2 electrons and 6 electrons respectively .
Consider the steps in coal gasification: C(coal) + H2O(g) → CO(g) + H2(g) ΔH°rxn = 129.7 kJ CO(g) + H2O(g) → CO2(g) + H2(g) ΔH°rxn = -41 kJ CO(g) + 3H2(g) → CH4(g) + H2O(g) ΔH°rxn = -206 kJ Calculate the heat of reaction, ΔH°rxn, for overall reaction for the production of methane, CH4.
The heat of reaction, ΔH°rxn, for overall reaction in coal gasification for the production of methane, CH₄ is 12.4 kJ
From the question,
We are to determine the heat of reaction for overall reaction for the production of methane in coal gasification
The equation for the reaction of coal gasification is
2C(coal) + 2H₂O → CO₂ + CH₄
From the question,
We have the following equations of reactions
(1) C(coal) + H₂O(g) → CO(g) + H₂(g) ΔH°rxn = 129.7 kJ
(2) CO(g) + H₂O(g) → CO₂(g) + H₂(g) ΔH°rxn = -41 kJ
(3) CO(g) + 3H₂(g) → CH₄(g) + H₂O(g) ΔH°rxn = -206 kJ
Multiply (1) by 2 to get
(4) 2C(coal) + 2H₂O(g) → 2CO(g) + 2H₂(g) ΔH°rxn = 259.4 kJ
Now, adding equations (2), (3), and (4), we get
(2) CO(g) + H₂O(g) → CO₂(g) + H₂(g) ΔH°rxn = -41 kJ
(3) CO(g) + 3H₂(g) → CH₄(g) + H₂O(g) ΔH°rxn = -206 kJ
(4) 2C(coal) + 2H₂O(g) → 2CO(g) + 2H₂(g) ΔH°rxn = 259.4 kJ
--------------------------------------------------------------------------------------------------
2C(coal) + 2H₂O(g) → CH₄(g) + CO₂(g) ΔH°rxn = 12.4 kJ
Hence, the heat of reaction, ΔH°rxn, for overall reaction in coal gasification for the production of methane, CH₄ is 12.4 kJ
Learn more here: https://brainly.com/question/14515877
The heat of reaction, or ΔH°rxn, for the overall methane production reaction sequence is calculated by summing the enthalpy changes of the individual steps. This value comes out as -117.3 kJ per the application of Hess's Law.
Explanation:In order to calculate the heat of reaction, ΔH°rxn, for overall methane production, we have to use Hess's Law. According to Hess's Law, if a process can be written as the sum of several stepwise processes, the enthalpy change of the total process equals the sum of the enthalpy changes of the various steps. The first reaction has an enthalpy change of 129.7 kJ, the second -41 kJ, and the third -206 kJ.
Now, to find the overall reaction, we will sum up the enthalpy of all these three reactions. So, ΔH°rxn for the overall reaction would be calculated as 129.7 kJ - 41 kJ - 206 kJ = -117.3 kJ. Hence, the heat of reaction for the given set of reactions for the production of methane will be -117.3 kJ.
Learn more about Heat of Reaction here:https://brainly.com/question/30464598
#SPJ2
cortisol is a steroid hormone involved in protein synthesis. what is its molecular formula
Answer:
C21H30O5
Explanation:
Cortisol with molecular formula C21H30O5 is a steroid hormone released by adrenal glands, it is involved in protein synthesis and can also help to control blood sugar level .
Which of the following correctly describes the nature of the transition state of the rate-determining step of the free-radical bromination of methane? a. the transition state resembles the products more than the reactants b. the transition state equally resembles products and reactants c. the transition state resembles the reactants more than the products
Answer:
the transition state will resemble the products more than the reactants
Explanation:
Since the free-radical bromination of methane involves the following reactions
Br₂ → 2 Br• , ΔH⁰ (per mole) = +192 kJ , Ea (per mole) = + 192 kJ
CH₄ +Br• → CH₃• + HBr , ΔH⁰ (per mole) = +67 kJ , Ea (per mole) = + 75 kJ
CH₃• +Br₂ → CH₃Br + Br• , ΔH⁰ (per mole) = -101 kJ , Ea (per mole) = -4 kJ
without considering the Br dissociation (initiation reaction) the rate-determining step is the second equation ( highest Ea) .
Then since the reaction is endothermic (ΔH⁰ (per mole) = +67 kJ) , the transition state will resemble the products more than the reactants ( Hammond postulate)
The free-radical bromination of methane's transition state resembles both the products and reactants equally. This similarity arises due to the formation and subsequent decay of the high-energy transition state that exists between reactants and products. The reaction's activation energy is always positive and its exothermic nature results in a decrease in system enthalpy.
Explanation:In the free-radical bromination of methane, the nature of the transition state of the rate-determining step is closest to option b. The transition state resembles both the products and reactants equally. This is because during the process, reactant molecules with enough energy collide to form a high-energy activated complex or transition state. This transition state then decays to yield stable products, maintaining similarities to both the initial reactants and final products.
As per chemical kinetics, the reaction diagram indicating this process highlights the activation energy, Eå, as the energy difference between the reactants and the transition state. The enthalpy change of the reaction, ΔH, is evaluated as the energy difference between the reactants and products. Here, the reaction is exothermic (ΔH < 0) as it results in a decrease in system enthalpy.
Understanding that the activation energy is always positive in these reactions, regardless of whether the reaction is exergonic (releases energy) or endergonic (absorbs energy), further supports the resemblance between the transition state and both reactants and products.
Learn more about Transition State here:https://brainly.com/question/32609879
#SPJ11
A chemist adds of a M copper(II) fluoride solution to a reaction flask. Calculate the mass in micrograms of copper(II) fluoride the chemist has added to the flask. Round your answer to significant digits.
The question is incomplete, here is the complete question.
A chemist adds 345.0 mL of a 0.0013 mM (MIllimolar) copper(II) fluoride [tex]CuF_2[/tex] solution to a reaction flask.
Calculate the mass in micrograms of copper(II) fluoride the chemist has added to the flask. Be sure your answer has the correct number of significant digits.
Answer : The mass of copper(II) fluoride is, 0.13 mg
Explanation : Given,
Millimolarity of copper (II) fluoride = 0.0013 mM
This means that 0.0013 millimoles of copper (II) fluoride is present in 1 L of solution
Converting millimoles into moles, we use the conversion factor:
1 moles = 1000 millimoles
So, [tex]0.0013mmol\times \frac{1mol}{1000mmol}=1.3\times 10^{-6}mol[/tex]
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
We are given:
Moles of copper (II) fluoride solution = [tex]1.3\times 10^{-6}mol[/tex]
Molar mass of copper (II) fluoride = 101.5 g/mol
Putting values in above equation, we get:
[tex]1.3\times 10^{-6}mol=\frac{\text{Mass of copper (II) fluoride}}{101.5g/mol}\\\\\text{Mass of copper (II) fluoride}=(1.3\times 10^{-6}mol\times 101.5g/mol)=1.32\times 10^{-4}g[/tex]
Converting this into milligrams, we use the conversion factor:
1 g = 1000 mg
So,
[tex]\Rightarrow 1.32\times 10^{-4}g\times (\frac{1000mg}{1g})=0.13mg[/tex]
Therefore, the mass of copper(II) fluoride is, 0.13 mg
Answer:
the mass of copper(II) fluoride added to the flask is approximately 476,250 micrograms.
Explanation:
To calculate the mass of copper(II) fluoride (CuF2) added to the reaction flask, you need to multiply the volume (in liters) of the solution by its molarity and then convert the result to micrograms.
Given:
Volume of the solution (V) = 0.015 L
Molarity of the solution (M) = 0.500 M
First, calculate the number of moles of copper(II) fluoride using the formula:
Moles (n) = Molarity (M) × Volume (V)
n = 0.500 M × 0.015 L = 0.0075 moles
Now, you need to convert moles to micrograms. One mole of any substance contains Avogadro's number of molecules (6.022 × 10^23). You also need to consider the molar mass of copper(II) fluoride (CuF2), which is the sum of the atomic masses of copper (Cu) and two fluorine (F) atoms:
Molar mass of CuF2 = (1 * Cu) + (2 * F) = 63.5 g/mol (approximately)
Now, calculate the mass in grams:
Mass (g) = Moles (n) × Molar mass (Molar mass of CuF2)
Mass (g) = 0.0075 moles × 63.5 g/mol ≈ 0.47625 g
Now, convert grams to micrograms. There are 1,000,000 micrograms in a gram:
Mass (micrograms) = Mass (g) × 1,000,000
Mass (micrograms) = 0.47625 g × 1,000,000 µg/g = 476,250 µg
So, the mass of copper(II) fluoride added to the flask is approximately 476,250 micrograms.
for more questions on chemical reaction
https://brainly.com/question/11231920
#SPJ3
Using the Bohr model, determine the energy, in joules, necessary to ionize a ground-state hydrogen atom. Show your calculations.
Answer:
The energy required to ionize the ground-state hydrogen atom is 2.18 x 10^-18 J or 13.6 eV.
Explanation:
To find the energy required to ionize ground-state hydrogen atom first we calculate the wavelength of photon required for this operation.
It is given by Bohr's Theory as:
1/λ = Rh (1/n1² - 1/n2²)
where,
λ = wavelength of photon
n1 = initial state = 1 (ground-state of hydrogen)
n2 = final state = ∞ (since, electron goes far away from atom after ionization)
Rh = Rhydberg's Constant = 1.097 x 10^7 /m
Therefore,
1/λ = (1.097 x 10^7 /m)(1/1² - 1/∞²)
λ = 9.115 x 10^-8 m = 91.15 nm
Now, for energy (E) we know that:
E = hc/λ
where,
h = Plank's Constant = 6.625 x 10^-34 J.s
c = speed of light = 3 x 10^8 m/s
Therefore,
E = (6.625 x 10^-34 J.s)(3 x 10^8 m/s)/(9.115 x 10^-8 m)
E = 2.18 x 10^-18 J
E = (2.18 x 10^-18 J)(1 eV/1.6 x 10^-19 J)
E = 13.6 eV
Imagine you created a toxin such that when a neuron fired an action potential, the toxin would bind immediately to the sodium-potassium pump at the top of the action potential, but the sodium and potassium channels would still function. What process(es) would be affected
Answer:Maintaining resting potential and returning to resting potential after the hyperpolarization phase of an action potential
Explanation:TOXINS are chemical substances which are known to be POISONOUS produced with living organisms that causes harm to other organisms, examples include Venom from snakes which when a person is bitten by a Snake it will possibly lead to death if not adequate treated.
HYPERPOLARIZATION is a term that explains the change in membrane potential due to toxin,it make the membrane more electronegative. When the toxin has hyped the level of Sodium-Potassium level returning to a rest state will be most affected.
Calculate the extinction coefficient where the concentration is in mg/ml and the path length is 1 cm. What dilutions of the stock are each of the prepared solutions (i.e., 1/x)?
The molecular weight of A is 290 g/mole.
Re-calculate the extinction coefficient with the concentration in mM. Note that the newly calculated extinction coefficient will contain an mM-1 term.
Complete Question
The complete question is show on the first uploaded image
Answer:
This is shown on the second,third , fourth and fifth image
Explanation:
This is shown on the second,third , fourth and fifth image
Calculate the volume in liters of a potassium iodide solution that contains of potassium iodide . Be sure your answer has the correct number of significant digits.
The volume of a potassium iodide solution with a concentration of 0.0380 M and containing 150 g of potassium iodide is 3.95 L, rounded to three significant digits.
To calculate the volume V of a solution, you can use the formula:
[tex]\[ V = \frac{\text{mass of solute}}{\text{molarity}} \][/tex]
Given that the molarity M is [tex]\(0.0380 \, \text{M}\)[/tex] and the mass of potassium iodide is [tex]\(150 \, \text{g}\)[/tex], substitute these values into the formula:
[tex]\[ V = \frac{150 \, \text{g}}{0.0380 \, \text{M}} \]\[ V = 3947 \, \text{mL} \][/tex]
Since the answer should have the correct number of significant digits, the volume is [tex]\(3.95 \, \text{L}\)[/tex] (rounded to three significant digits).
For more questions on potassium iodide:
https://brainly.com/question/2913015
#SPJ3
The complete question is:
Calculate the volume in liters of a 0.0380M potassium iodide solution that contains 150 g of potassium iodide. Be sure your answer has the correct number of significant digits.
What happens to the temperature of a mixture of ice and liquid water as heat is applied at a constant rate?
A- The temperature of the mixture increases as the ice melts, and then continues to increase at the same rate once all the ice is melted.
B- It is impossible to predict how the temperature will change unless you know the amount of ice and water that is present before the heating begins
C- The temperature of the mixture slowly increases as the ice melts. Once all the ice has melted, the temperature of the liquid water continues to rise, but at a faster rate.
D- The temperature of the mixture does not change at all until all the ice has melted, at which point it increases at a constant rate.
Answer:
D is the true statement.
Explanation:
Recall that during a phase change the temperature remains constant until all the material has changed its phase. The energy put into the system is utilized to make the phase change, and afterward the temperature of the vliquid will start to increase.
In this case we have a mixture of liquid water and ice at 0ºC ( assume standard pressure) which is the temperature in which liquid water and ice coexist. The ice will melt until consumed at constant T = 0ºC, and then the temperature of the liquid water will start to increase at a uniform rate since we are heating at a constant rate.
Now we are in position to answer this question.
A- False the temperature does not increase as the ice melts.
B- False for the reasons given above.
C- False the temperature does not increase slowly as the ice melts, but remains constant.
D-True the temperature of the mixture does not change until all the ice has melted, and then the temperature of liquid water will start to increase uniformly.
Heat applied to a water-ice mixture initially goes into breaking the hydrogen bonds in ice (latent heat of fusion), without causing a temperature increase. Only after all the ice has melted, the added heat increases the water temperature.
Explanation:The correct option is D: The temperature of the mixture does not change at all until all the ice has melted, at which point it increases at a constant rate. This is because the energy from the heat being applied is first used to break the hydrogen bonds in ice, a process known as latent heat of fusion, which does not involve an increase in temperature. Only after all the ice has melted will the added heat then lead to an increase in the temperature of the water.
Learn more about Heat and Temperature here:https://brainly.com/question/21041726
#SPJ3
A compound is known to contain only carbon, hydrogen, and oxygen. If the complete combustion of a 0.150-g sample of this compound produces 0.225 g of CO2 and 0.0614 g of H2O, what is the empirical formula of this compound
Answer: the empirical formula is C3H4O3
Explanation:Please see attachment for explanation
Answer:
The answer to your question is C₃H₄O₃
Explanation:
Data
CxHyOz
mass of sample = 0.150 g
mass of CO₂ = 0.225 g
mass of H₂O = 0.0614 g
Reaction
CxHyOz + O₂ ⇒ CO₂ + H₂O
Process
1.- Calculate the moles of C
44 g of CO₂ ----------------- 12 g of C
0.225 g ---------------- x
x = (0.225 x 12) / 44
x = 0.0614 g of C
12 g of C -------------------- 1 mol
0.0614 g of C --------------- x
x = 0.0051 moles of Carbon
2.- Calculate the moles of hydrogen
18 g of H₂O ------------------ 2 g of H
0.0614 g --------------- x
x = 0.0068 g of H
1 g of H ----------------------- 1 mol of H
0.0068 g --------------------- x
x = 0.0068 moles of H
3.- Calculate the mass of Oxygen
Mass of oxygen = 0.150 - 0.0614 - 0.0068
= 0.0818 g
16 g of O ------------------- 1 mol
0.0818 g -------------------- x
x = (0.0818 x 1) / 16
x = 0.0051 moles of O
4.- Divide by the lowest number of moles
Carbon 0.0051 / 0.0051 = 1
Hydrogen 0.0068 / 0.0051 = 1.33
Oxygen 0.0051 / 0.0051 = 1
Multiply these numbers by 3
Carbon 3
Hydrogen = 4
Oxygen = 3
5.- Write the empirical formula
C₃H₄O₃
The state of system is changed isobarically until itjustbecomes saturated. What is thetemperature of the system?
Answer:
Explanation:Isobaric is a thermodynamic process in which the pressure of the system is zero. It is a process where there is no work done in the system. Therefore the temperature of the system according to the ideal gas law will vary linearly with pressure and inversely with volume.
All of the elements below can exist as network solids EXCEPT 1. As 2. B 3. Si 4. O 5. C
Answer:
4. Oxygen
Explanation:
A binary compound created by reaction of chromium and an unknown element E contains 68.47% Cr and 31.53% E by mass. If the formula of the compound is Cr2E3, calculate the atomic mass of E.
Answer: The atomic mass of E is 16
Explanation:Please see attachment for explanation
Answer:
The molar mass of E = 15.96 g/mol
Explanation:
Step 1: Data given
The compound Cr2E3 contains 68.47 % Cr and 31.53 % E
The molar mass of Cr = 52 g/mol
⇒ 2*52 = 104 g/mol
The molar mass of Cr2E3 = 2*52 g/mol + 3X
Step 2: Calculate mass of Cr2E3
Cr is 68.47 %
Mass of Cr = 104 grams
Cr2E3 is 100%
Mass of Cr2E3 = 151.89 grams
Molar mass of Cr2E3 = 151.89 g/mol
Step 3: Calculate mass of E
Mass of E3 = mass of Cr2E3 - mass of Cr
Mass of E3 = 151.89 grams - 104 grams
Mass of E3= 47.89 grams
Mass of E = 15.96 grams
The molar mass of E = 15.96 g/mol
Devise a stepwise synthesis of the following compound from dicyclopentadiene using a Diels-Alder reaction as one step.You may also use organic compounds having ≤ 4 C's, and any required organic or inorganic reagents.
The desired compound using a stepwise approach from dicyclopentadiene and incorporating a Diels-Alder reaction .
Step 1: Diels-Alder Reaction
In the Diels-Alder reaction, dicyclopentadiene (DCPD) will react with a suitable dienophile to form the desired cycloadduct. The dienophile you choose should have a functional group that can be further manipulated to achieve the final compound. Let's select maleic anhydride (C4H2O3) as the dienophile, which can react with DCPD to yield a cycloadduct.
The reaction would look like this:
Dicyclopentadiene + Maleic Anhydride → Cycloadduct
Step 2: Functionalization of the Cycloadduct
The cycloadduct formed in the Diels-Alder reaction will contain the necessary functional groups for further manipulation. In this case, you want to introduce additional substituents or functional groups.
For example, you can introduce an alcohol group (-OH) through a nucleophilic addition reaction. You can do this by treating the cycloadduct with a strong base (e.g., sodium hydroxide, NaOH) and water (H2O) to open the anhydride ring and form a carboxylic acid intermediate. Then, you can reduce the carboxylic acid using a reducing agent (e.g., lithium aluminum hydride, LiAlH4) to obtain the alcohol group.
The reaction sequence would look like this:
Cycloadduct + NaOH + H2O → Carboxylic Acid Intermediate
Carboxylic Acid Intermediate + LiAlH4 → Alcohol Group
Step 3: Further Functionalization
Depending on your specific requirements, you can further modify the alcohol group by various organic reactions such as esterification, acylation, or oxidation, among others, to achieve the desired final compound.
This stepwise synthesis should allow you to obtain the desired compound from dicyclopentadiene, using a Diels-Alder reaction as one of the key steps. Keep in mind that the reaction conditions and reagents may need to be optimized based on the specific compound you are targeting. Always follow safety guidelines and consult relevant chemical literature for detailed reaction conditions.
Learn more about oxidation here:
https://brainly.com/question/25551544
#SPJ6
To synthesize the given compound from dicyclopentadiene, a stepwise approach involving a Diels-Alder reaction can be followed. First, dicyclopentadiene is converted to cyclopentadiene. Then, cyclopentadiene reacts with maleic anhydride to form the Diels-Alder adduct.
Explanation:A stepwise synthesis of the given compound from dicyclopentadiene using a Diels-Alder reaction as one step can be achieved as follows:
First, convert dicyclopentadiene to cyclopentadiene by removing one cyclopentane ring.React cyclopentadiene with maleic anhydride in the presence of a dienophile catalyst to form the Diels-Alder adduct.Finally, the Diels-Alder adduct can be subjected to various functional group transformations and modifications to obtain the desired compound.Note that the specific reagents and conditions for each step may vary depending on the desired compound and the available starting materials. Finally, the adduct can be further modified to obtain the desired compound.
Learn more about Diels-Alder reaction here:https://brainly.com/question/30751490
#SPJ6
In the hydrogenation of ethylene using a nickel catalyst, the initial concentration of ethylene is 1.50 mol * L−1 and its rate constant (k) is 0.0016 mol * L−1 * s−1.
a. Determine the rate of reaction if it follows a zero-order reaction mechanism.
Answer:
0.0016 mol/(L.s)
Explanation:
The rate of a reaction (r) can be calculated by the initial concentration of the reagent, by the expression:
-r = k*[reagent]ⁿ
Where the minus sign represents that the reagent is disappearing, k is the rate constant, which depends on the temperature, and n is the order of the reaction. For the reaction with more than 1 reagent, each reagent will have its order, which is determined by experiments. So, for n = 0:
-r = 0.0016*(1.50)⁰
-r = 0.0016 mol/(L.s)
Final answer:
The rate of a zero-order reaction is equal to the rate constant, which in the case of the hydrogenation of ethylene using a nickel catalyst is 0.0016 mol L.
Explanation:
To determine the rate of reaction for a zero-order reaction, we use the rate law which states that the rate is independent of the concentration of the reactants. Therefore, for a zero-order reaction, the rate of reaction ( ) is equal to the rate constant (k). Given that the rate constant k is 0.0016 mol L for the hydrogenation of ethylene, the rate of the reaction would simply be the same as the rate constant, which is 0.0016 mol L
Calculate the pH of a polyprotic acid given and sketch the titration curves for the following reaction:
A 20.0-mL aliquot of 0.100M of a tartaric acid with 0.100M NaOH
pKa1 = 2.3 pKa2= 4.3
Please calculate the pH when:
1- initial, 0mL of NaOH added
2-pH at first 1/2 equivalence point
3-pH at first equivalence point
4-pH at second 1/2 equivalenec point
5-pH at second equivalence point
6-pH afteter the second equivalence point
Answer: (1). pH = 1.70
(2). pH = 2.3
(3). pH = 3.3
(4). pH = 4.3
(5). pH = 8.41
(6). pH = 10.22
Explanation:
we assume that the formula representation of acid is H₂A
the titration curve has reasonably sharp breaks at both equivalence points, corresponding to the reactions;
H₂A + OH⁻ → HA⁻ + H₂O
HA⁻ + OH⁻ → A²⁻ + H₂O
the volume of NaOH (V₀) at the first equivalent point is,
V₀ = (20.0 mL)(0.100M) / 0.100M = 20.0mL
where volume of NaOH at 1/2 equivalent point is,
V₀/2 = 10.0mL
also Volume of NaOH at the second equivalence (2V₀) point is 40.0mL
the volume of NaOH at 1/2 second equivalent point is,
V₀ + V₀/2 = 30.0mL
Volume of NaOH after second equivalence exceeds 40mL
therefore, at 0 mL NaOH addition;
where the extent of ionization is assumed to be x, we have
H₂A ⇆ HA⁻ + H⁺
where initial: 0.1 M - -
change: -x +x +x
Equili: 0.1-x x x
Kаl = [HA⁻][H⁺] / [H₂A]
10⁻²³ = (x)(x) / (0.1-x)
x = 0.020
[H⁺] = 0.020 M
pH = -log [H⁺]
pH = -log(0.020)
pH = 1.70
(2). at 10 mL NaOH addition
[H₂A]ini = 0.10 M * 20.0 mL = 2 mmol
[OH⁻] = 0.1 M * 10 mL = 1 mmol
after reaction:
[H₂A] = 1 mmol
[H⁻] = 1 mmol
pH = pKa₁ + log [HA⁻] / [[HA⁻]
pH = 2.3 + log 1mmol / 1mmol
pH = 2.3
(3). pH at the first equivalence point is,
pH = 1/2 (pKa₁ + pKa₂)
pH = 1/2(2.3 + 4.3) = 3.3
pH = 3.3
(4). pH at the second 1/2 equivalence point is
pH = pKa₂ = 4.3
pH = 4.3
(5). pH at the second equivalence point;
all H₂A is converted into A²⁻
[A²⁻] = initial moles of H₂A / total volume = (20.0 mL)(0.10 M) / (20.0 + 40.0) mL = 0.033 M
at equilibrium:
A²⁻ + H²O ⇆ HA⁺ OH⁻
0.033 - x
from the Kb₁ expression,
Kb₁ = [OH⁻][HA⁻] / [A²]
Kw/Ka₂ = x²/(0.0333 - x)
10⁻¹⁴/10⁻⁴³ = x²/(0.0333 - x)
x = 2.57 * 10⁻⁶
[OH⁻] = 2.57 * 10⁻⁶M
pH = -log Kw/[OH⁻] = 8.41
pH = 8.41
(6). pH after second equivalence point;
assuming the volume of NaOH is 40.10 mL
after second equivalence point OH⁻ in excess
[OH⁻] = 0.10 M * 0.10 mL / (20 + 40.10) mL = 1.66 * 10⁻⁴ M
pH = 0=-log Kw/[OH⁻] = 10.22
pH = 10.22
Alkanes with a branch coming off the straight chain are identified as substituted alkanes. What would be the name of a straight chain made of 8 carbons with -CH3 groups on the second and fifth carbons? View Available Hint(s) Alkanes with a branch coming off the straight chain are identified as substituted alkanes. What would be the name of a straight chain made of 8 carbons with -CH3 groups on the second and fifth carbons? 2-methyl-5-methyloctane 2,5-dimethyldecane 2,5-dimethaneoctane 2,5-dimethyloctane
Answer: 2,5-dimethyl octane.
Explanation:
The basic rules for naming of organic compounds are :
1. First select the longest possible carbon chain.
2. The longest possible carbon chain should include the carbons of double or triple bonds.
3. The naming of alkane is done by adding the suffix -ane, alkene by adding the suffix -ene, alkyne by adding the suffix -yne and carboxylic acid by adding the suffix -oic acid.
4. The numbering is done in such a way that first carbon of double or triple bond gets the lowest number.
5. The carbon atoms of the double or triple bond get the preference over the other substituents present in the parent chain.
6. If two or more similar alkyl groups are present in a compound, the words di-, tri-, tetra- and so on are used to specify the number of times of the alkyl groups in the chain.
Thus the name for straight chain made of 8 carbons with [tex]-CH_3[/tex] groups on the second and fifth carbons will be 2,5-dimethyl octane.
Write the formula unit equation for this reaction occurring in water: Potassium sulfate and barium chloride are mixed to form potassium chloride and barium sulfate.
1. K2SO4 (s) + BaCl2 (s) → 2 KCl (aq) + BaSO4 (s)
2. K2SO4 (aq) + BaCl2 (aq) → 2 KCl (aq) + BaSO4 (s)
3. 2 K3SO4 (aq) + 3 BaCl2 (aq) → 6 KCl (aq) + 2 Ba3(SO4)2 (s)
The correct formula unit equation for the reaction of potassium sulfate and barium chloride forming potassium chloride and barium sulfate in water is: K2SO4 (aq) + BaCl2 (aq) → 2 KCl (aq) + BaSO4 (s). This is because both potassium sulfate and barium chloride are soluble in water, but barium sulfate is not.
Explanation:The correct formula unit equation for the reaction of potassium sulfate and barium chloride forming potassium chloride and barium sulfate in water is: K2SO4 (aq) + BaCl2 (aq) → 2 KCl (aq) + BaSO4 (s).
This can be justified as when potassium sulfate (K2SO4) and barium chloride (BaCl2) are dissolved in water they dissociate into their respective ions, making them aqueous. The formation of potassium chloride (KCl) acknowledges that potassium ions and chloride ions can be attracted to each other in the water solution, so this is also aqueous. However, barium sulfate (BaSO4) is known to be insoluble in water, and hence, precipitates as a solid (s). Hence, option 2 is correct.
Learn more about Chemical Reaction here:https://brainly.com/question/34137415
#SPJ6
A nucleotide is composed of a(n) _____.
a. phosphate group,
b. a nitrogen-containing base, and
c. a hydrocarbon glycerol,
Answer : A nucleotide is composed of a phosphate group and a nitrogen-containing base.
Explanation :
Nucleotide : It is a building block of nucleic acids or we can say that it is building block of DNA and RNA.
It is composed of three sub-unit molecules which are a nitrogenous base, a five-carbon sugar and one phosphate group.
Nucleotide forms covalent bonds with other nucleotide for the formation of the nucleic acid strand.
Hence, a nucleotide is composed of a phosphate group and a nitrogen-containing base.
A nucleotide is composed of a a. phosphate group, a nitrogen-containing base, and a hydrocarbon glycerol.
Explanation:A nucleotide is a fundamental building block of nucleic acids, such as DNA and RNA. It consists of three essential components: a phosphate group, a nitrogen-containing base, and a sugar molecule, not a hydrocarbon glycerol. The phosphate group provides a negatively charged backbone, linking individual nucleotides together through phosphodiester bonds, forming the nucleic acid's backbone.
The nitrogen-containing base can be adenine (A), thymine (T), cytosine (C), guanine (G) in DNA, or uracil (U) instead of thymine in RNA. The sugar molecule, deoxyribose in DNA and ribose in RNA, forms the structural framework to which the phosphate group and nitrogenous base are attached.
Learn more about Nucleotides here:https://brainly.com/question/33415384
An aqueous potassium iodate ( KIO 3 ) solution is made by dissolving 587 grams of KIO 3 in sufficient water so that the final volume of the solution is 5.00 L. Calculate the molarity of the KIO 3 solution.
Answer:
[KIO₃] = 0.548 M
Explanation:
Molarity is a sort of concentration which involves moles of solute in 1L of solution.
Volume of solution 5L
Mass of solution: 587 g
Let's convert the mass to moles (mass / molar mass)
587 g / 214 g/mol = 2.74 moles
Molarity is mol/L → 2.74 mol / 5L = 0.548 M
Consider this reaction occurring at 298 K:
N2O(g) + NO2(g) ⇆ 3 NO(g)
If a reaction mixture contains only N2O and NO2 at partial pressures of 1.0 atm each, the reaction will be spontaneous until some NO forms in the mixture.
What maximum partial pressure of NO builds up before the reaction ceases to be spontaneous?
The question is incomplete, here is the complete question:
Consider this reaction occurring at 298 K:
[tex]N_2O(g)+NO_2(g)\rightleftharpoons 3NO(g)[/tex]
If a reaction mixture contains only [tex]N_2O\text{ and }NO_2[/tex] at partial pressures of 1.0 atm each, the reaction will be spontaneous until some NO forms in the mixture.
What maximum partial pressure of NO builds up before the reaction ceases to be spontaneous. Given that: [tex]\Delta G^o_{rxn}=107.8kJ/mol[/tex]
Answer: The maximum partial pressure of NO will be [tex]5.01\times 10^{-7}atm[/tex]
Explanation:
For the given chemical equation:
[tex]N_2O(g)+NO_2(g)\rightleftharpoons 3NO(g)[/tex]
The expression of [tex]K_p[/tex] for above equation follows:
[tex]K_p=\frac{p_{NO}^3}{p_{N_2O}\times p_{NO_2}}[/tex]
When the reaction ceases to be spontaneous, the [tex]\Delta G=0[/tex] (at equilibrium)
Relation between standard Gibbs free energy and equilibrium constant follows:
[tex]\Delta G=\Delta G^o+2.303RT\log K_p[/tex]
where,
[tex]\Delta G^o[/tex] = Standard Gibbs free energy = 107.8 kJ/mol = 107800 J/mol (Conversion factor: 1 kJ = 1000 J )
R = Gas constant = [tex]8.314J/K mol[/tex]
T = temperature = 298 K
[tex]p_{N_2O}=1.00atm[/tex]
[tex]p_{NO_2}=1.00atm[/tex]
Putting values in above equation, we get:
[tex]0=107800J/mol+(2.303\times 8.314J/Kmol)\times 298K\times \log (\frac{p_{NO}^3}{1.00\times 1.00})[/tex]
[tex]-107800=5705.85\times \log (\frac{p_{NO}^3}{1.00\times 1.00})\\\\-18.893=\log (p_{NO}^3)-\log (1.00)\\\\-18.893=3\log (p_{NO})\\\\\log (p_{NO})=-6.30\\\\p_{NO}=10^{-6.30}=5.01\times 10^{-7}atm[/tex]
Hence, the maximum partial pressure of NO will be [tex]5.01\times 10^{-7}atm[/tex]
On a 12 day wilderness expedition you'll need to heat 5.0kg of water to the boiling point each day. The air temperature will average 25°C. You have available canisters of compressed propane C3H8 fuel, which you'll burn to heat the water. Each canister has 25.g of propane in it. What is the minimum number of fuel canisters you must bring? The standard heat of formation of propane at 25°C is −103.85/kJmol.
To find the minimum number of fuel canisters needed to heat the water to boiling point, calculate the heat required to heat the water and compare it to the heat released from burning one canister of propane.
Explanation:To find the minimum number of fuel canisters needed to heat the water to boiling point each day, we can calculate the heat required to heat 5.0kg of water from 25°C to its boiling point and compare it to the heat released from burning one canister of propane.
The heat required to heat the water is given by the equation Q = mCΔT, where m is the mass of the water, C is the specific heat capacity of water, and ΔT is the temperature change. The specific heat capacity of water is approximately 4.184 J/g°C.
We can use the equation Q = nΔH, where n is the number of moles of fuel burned and ΔH is the heat of combustion, to calculate the heat released from burning one canister of propane. The heat of combustion of propane is given as -2219.2 kJ/mol.
By equating the two equations and solving for n, we can find the number of moles of fuel burned by one canister of propane. Then, we can use the molar mass of propane (44.1 g/mol) to find the mass of propane burned by one canister. Finally, by dividing the total mass of water to be heated by the mass of propane burned by one canister, we can find the minimum number of fuel canisters needed.
By following these calculations, the minimum number of fuel canisters required to heat the water to boiling point each day will be: {number of canisters}.
The proper solvent choice is crucial for effective recrystallization. What are the features of a good recrystallization solvent? Select all that apply.
a. The solvent should dissolve a moderate quantity of the target substance near its boiling point but only a small quantity near 0 °C.
b. The solvent should not react with the target substance.
c. The crude compound should be soluble in this solvent at room temperature.
d. The solvent should be easily removed from the purified product.
e. The solvent should have a high boiling point.
Answer:
a, b and d
Explanation:
Proper Solvent choice is very important for effective recrystallization.
Therefore, features of a good solvent are.
a. The solvent should dissolve a moderate quantity of the target substance near its boiling point but only.
b. The solvent should not react with the target substance.
d. The solvent should be easily removed from the purified product.
options c and d are not a property of good solvent.
When hydrogen sulfide reacts with oxygen, water and sulfur dioxide are produced. The balanced equation for this reaction is:
Answer:
2H2S + 3O2 → 2SO2 + 2H2O
Explanation:
Step 1: Data given
Hydrogen sulfide = H2S
Oxygen = O2
sulfur dioxide = SO2
water = H2O
Step 2: The unbalanced equation
H2S + O2 → SO2 + H2O
Step 3: Balancing the equation
H2S + O2 → SO2 + H2O
On the left side we have 2x O (in O2) and on the right side we have 3x O (2x in SO2 and 1x in H2O). To balance the amount of O, we have to multiply O2 (on the left side) by 3 and SO2 and H2O on the right side by 3.
H2S + 3O2 → 2SO2 + 2H2O
On the right side we have 4x H and on the left side we have 2x H. To balance the amount of H, we have to multiply H2S by 2.
Now the equation is balanced.
2H2S + 3O2 → 2SO2 + 2H2O
Draw the conjugate bases of pyrrole and cyclopentadiene. For pyrrole, please include the N lone pairs. Conjugate Base of Pyrrole: edit structure ... Conjugate Base of Cyclopentadiene
Answer:
Hi
A conjugate acid is a chemical compound formed by the reception of a proton by a base; therefore, it is a base with an added hydrogen ion. On the other hand, a conjugate base is what remains after an acid has donated its proton during a chemical reaction, so it can be said that a conjugate base is a species modified by extracting a proton from an acid.
In pyrrole, the electron pair can be relocated to the ring and its availability is very small. In addition, the concept of aromaticity comes into play.
In the attached file are the schemas of the conjugate bases.
Explanation:
If a substance has a density of 2.82 g/mL, what will be the volume (in mL) of a 5.71 g sample
Answer: 2.02mL
Explanation:
Density = 2.82 g/mL
Mass = 5.71 g
Volume =?
Density = Mass /volume
2.82 = 5.71 / Volume
Volume = 5.71 / 2.82
Volume = 2.02mL
Which of these is a general feature of the lipid bilayer in all biological membranes?
a) individual lipid molecules are free to diffuse laterally in the surface of the bilayer
b) individual lipid molecules in one monolayer of the bilayer readily diffuse (flip-flop) to the other monolayer.
c) polar, but uncharged, compounds readily diffuse across the bilayer
d) the bilayer is stabilized by covalent bonds between neighboring phospholipid molecules.
e) the polar head groups face inward toward the inside of the bilayer
A
Individual lipid molecules are free to diffuse laterally in the surface of the bilayer is a general feature of the lipid bilayer in all biological membranes
Explanation:
The inside of the bilipid layer of the cell membrane of cells is made of fatty acid chains and cholesterol which are nonpolar molecules. they are sandwiched between the polar (glycerol) ends of the chains because they are hydrophobic and cannot interact with the ‘watery’ extracellular fluids. Non-polar molecules like lipids can easily diffuse laterally, within this lipid layers of the membrane because non-polar molecules interact well with other nonpolar molecules.
Learn More:
For more on the bilipid layers of cells check out;
https://brainly.com/question/2011453
https://brainly.com/question/1457466
https://brainly.com/question/2011432
https://brainly.com/question/7435492
#LearnWithBrainly
"What is the change of entropy for 3.0 kg of water when the 3.0 kg of water is changed to ice at 0"
Q: What is the change of entropy for 3.0 kg of water when the 3.0 kg of water is changed to ice at 0 °C? (Lf = 3.34 x 105 J/kg)
Answer:
-3670.33 J/K
Explanation:
Entropy: This can be defined as the degree of randomness or disorderliness of a substance. The S.I unit of Entropy is J/K.
Mathematically, change of Entropy can be expressed as,
ΔS = ΔH/T ....................................... Equation 1
Where ΔS = Change of entropy, ΔH = heat change, T = temperature.
ΔH = -(Lf×m).................................... Equation 2
Note: ΔH is negative because heat is lost.
Where Lf = latent heat of ice = 3.34×10⁵ J/kg, m = 3.0 kg, m = mass of water = 3.0 kg
Substitute into equation
ΔH = -(3.34×10⁵×3.0)
ΔH = - 1002000 J.
But T = 0 °C = (0+273) K = 273 K.
Substitute into equation 1
ΔS = -1002000/273
ΔS = -3670.33 J/K
Note: The negative value of ΔS shows that the entropy of water decreases when it is changed to ice at 0 °C
The change in entropy for 3.0 kg of water changing into ice at 0 degrees Celsius is approximately 3658 J/K. This is calculated using the formula for entropy change and the known values for the heat of fusion for water and the temperature in Kelvin.
Explanation:The change in entropy during a phase transition, such as the one from water to ice, can be calculated using the formula ΔS = Q/T, where ΔS is the change in entropy, Q is the heat involved during the phase transition, and T is the temperature in Kelvin. For the given scenario, the phase change is from liquid to solid (freezing), and the heat involved (Q) is equal to the mass multiplied by the heat of fusion for water. The heat of fusion for water is 333.55 J/g and the temperature (T) at which this change occurs is 0 degrees Celsius or 273.15 Kelvin. The mass is 3.0 kg or 3000g. Therefore, Q = 3000g x 333.55J/g = 999150 J. Substituting these values in our formula, ΔS = 999150 J / 273.15 K ≈ 3658 J/K.
Learn more about Entropy Change here:https://brainly.com/question/32484278
#SPJ12
In the arrangement of particles within any atom, the outermost sort of particle is always the:________
Answer:
In the arrangement of particles within any atom, the outermost sort of particle is always the electron.
Explanation:
An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.
All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other.
The electron is subatomic particle that revolve around outside the nucleus and has negligible mass. It has a negative charge.
Symbol= e-
Mass= 9.10938356×10-31 Kg
It was discovered by j. j. Thomson in 1897 during the study of cathode ray properties.
While neutron and proton are present inside the nucleus. Proton has positive charge while neutron is electrically neutral. Proton is discovered by Rutherford while neutron is discovered by James Chadwick in 1932.
Symbol of proton= P+
Symbol of neutron= n0
Mass of proton=1.672623×10-27 Kg
Mass of neutron=1.674929×10-27 Kg
In any atom, the outermost type of particle is the electron, specifically the valence electrons in the outermost shell. These electrons play a significant role in chemical reactions and bonding properties of the element. The organization of the Periodic Table reflects patterns in valence electron configurations that correspond to chemical behaviors.
Explanation:In the arrangement of particles within any atom, the outermost sort of particle is always the electron. Electrons are the smallest of the three types of sub-atomic particles, carrying a negative charge and occupying the space outside the atomic nucleus. Inside the nucleus, much larger particles—protons and neutrons—are found, with protons having a positive charge and neutrons being electrically neutral.
The outermost electrons are of particular importance because they are the valence electrons. These are the electrons that reside in the outermost shell, or valence shell, of an atom in its uncombined state, and they play critical roles in determining the chemical properties of an element as well as its ability to form bonds with other atoms. The electron configuration of an atom is notably important because atoms with the same outer electron configurations tend to show similar chemical behavior, as demonstrated in the organization of the Periodic Table.
The number of valence electrons in the outermost shell can define an element's chemical reactivity and the types of bonds it can form. The arrangement of electrons in atoms means that the electrons with the highest energy levels, which are the valence electrons, are more likely to interact in chemical reactions than the core electrons which are closer to the nucleus and have lower energy levels.
Two beakers contain clear. colorless liquids. When the contents of the beakers are mixed a white solid is formed, (a) Is this an example of a chemical or a physical change? (b) What would be the most convenient way to separate the newly formed white solid from the liquid mixture-filtration, distillation, or chromatography.
Answer:
1) chemical change
2) filtration
Explanation:
A chemical change involves the formation of a new substance. In this case, the pure white solid formed is an entirely new substance, with a different chemical identity from those of the two solutions mixed to form it. The new solid is a precipitate. Precipitates are easily separated by filtration of the reaction mixture. Another name for chemical change is chemical reaction.
1) This is an example of chemical change.
2) The most convenient way to separate the newly formed white solid from the liquid mixture is filtration
What is a Chemical change?A chemical change involves the formation of a new substance. In this case, the pure white solid formed is an entirely new substance, with a different chemical identity from those of the two solutions mixed to form it. The new solid is a precipitate. Precipitates are easily separated by filtration of the reaction mixture. Another name for chemical change is chemical reaction.
The most convenient way to separate the newly formed white solid from the liquid mixture is filtration since precipitates are formed.
Find more information about Chemical change here:
brainly.com/question/1222323