Answer : The heat released during the reaction is [tex]-8.4\times 10^3kJ[/tex]
Explanation :
First we have to calculate the number of moles of octane [tex](C_8H_{18})[/tex].
[tex]\text{Moles of }C_8H_{18}=\frac{\text{Mass of }C_8H_{18}}{\text{Molar mass of }C_8H_{18}}[/tex]
Molar mass of [tex]C_8H_{18}[/tex] = 114 g/mole
[tex]\text{Moles of }C_8H_{18}=\frac{75g}{114g/mole}=0.658mole[/tex]
Now we have to calculate the heat released during the reaction.
[tex]\Delta H=\frac{q}{n}[/tex]
or,
[tex]q=\Delta H\times n[/tex]
where,
[tex]\Delta H[/tex] = enthalpy change = -5500 kJ/mol
q = heat released = ?
n = number of moles of [tex]C_8H_{18}[/tex] = 0.658 mol
Now put all the given values in the above formula, we get:
[tex]q=(-5500kJ/mol)\times (0.658mol)=-8358.66kJ=-8.4\times 10^3kJ[/tex]
Therefore, the heat released during the reaction is [tex]-8.4\times 10^3kJ[/tex]
The quantity of heat released when the octane is burned completely is -3,613.5 Joules.
Given the following data:
Mass of octane = 75 gramsEnthalpy of combustion = -5,500 kJ/molTo find the quantity of heat released when the octane is burned completely:
First of all, we would determine the number of moles of octane in this chemical reaction.
[tex]Number\;of\;moles \;(C_8H_{18})= \frac{Mass\; of\;octane}{Molar\;mass\;of\;octane}[/tex]
Substituting the values into the formula, we have;
[tex]Number\;of\;moles \;(C_8H_{18})= \frac{75}{114.23}[/tex]
Number of moles ([tex]C_8H_{18}[/tex]) = 0.657 moles.
Now, we can find the quantity of heat released when the octane is burned completely:
1 mole of octane = -5,500 kJ/mol
0.657 mole of octane = X kJ/mol
Cross-multiplying, we have:
[tex]X = -5500[/tex] × [tex]0.657[/tex]
X = -3,613.5 Joules.
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At 25 °c only 0.0700 mol of the generic salt ab is soluble in 1.00 l of water. what is the ksp of the salt at 25 °c?
A piece of copper metal is dipped into an aqueous solution of agno3. which net ionic equation describes the reaction that occurs?
Answer: The net chemical equation is written below.
Explanation:
When copper metal displaces an aqueous solution of silver nitrate, it leads to the formation of silver metal and aqueous copper nitrate solution.
This reaction is an example of single displacement reaction.
Net ionic equation of any reaction does not include any spectator ions.
Spectator ions are defined as the ions which does not get involved in a chemical equation. They are found on both the sides of the chemical reaction when it is present in ionic form.
The chemical equation for the reaction of copper metal and silver nitrate is given as:
[tex]Cu(s)+2AgNO_3(aq.)\rightarrow Cu(NO_3)_2(aq.)+2Ag(s)[/tex]
Ionic form of the above equation follows
[tex]Cu(s)+2Ag^+(aq.)+2NO_3^-(aq.)\rightarrow Cu^{2+}(aq.)+2NO_3^-(aq.)+2Ag(s)[/tex]
As, nitrate ions are present on both the sides of the reaction. Thus, it will not be present in the net ionic equation and are spectator ions.
The net ionic equation for the above reaction follows:
[tex]Cu(s)+2Ag^+(aq.)\rightarrow Cu^{2+}(aq.)+2Ag(s)[/tex]
Hence, the net ionic equation is written above.
When an atom releases gamma radiation,
A. the mass number decreases by one.
B. the atomic number decreases by one.
C. the mass number increases by four.
D. the atomic number remains the same.
Answer: The correct answer is Option D.
Explanation:
Gamma radiations are released when an atom undergoes gamma decay. During this decay process, a unstable nuclei gives off excess energy through a spontaneous electromagnetic process and it further releases [tex]\gamma -radiations[/tex]. The radiations released does not carry any charge and hence are electrically neutral.
Atomic number of the atom going this decay does not change.
[tex]_Z^A\textrm{X}^*\rightarrow _Z^A\textrm{X}+_0^0\gamma[/tex]
Thus, the correct answer is Option D.
Which is a typical characteristic of an ionic compound?
a. electron pairs are shared among atoms.
b. the ionic compound has a low solubility in water.
c. the ionic compound is described as a molecule?
Answer:
Chemistry A Unit 4: Chemical bonding Lesson 5: Molecular compounds
1. D. The ionic compound has a high meting point.
2. A. The arrangement of bonded atoms
Explanation:
Ionic compounds have a high melting point is a typical characteristic of an ionic compound.
What are ionic compounds?Ionic compounds can be defined as crystalline solids generated by closely packed ions of opposite charge. An Ionic compound is commonly formed whenever metal reacts with nonmetal.
In ionic compounds, the ions are generally held by ionic bonds. The ions are created by losing or gaining electrons to get their nearest noble gas configuration.
In a reaction, the metals lose electrons to gey filled octet while non-metals will gain electrons to get a complete octet.
Ionic compounds have high melting points and are hard as well as brittle. They dissociate into ions whenever dissolved in water. Solutions of ionic compounds can conduct electricity even in the molten state, but solid materials do not.
Ionic compounds form crystals and have higher enthalpies of fusion as well as vapourization than molecular compounds.
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The product formation was decreased when a substance b was added to an enzyme reaction. more substrate being added did not increase the amount of produce formed. based on this we assume that substance b could be
Oxygen has an electronegativity of 3.5, and carbon has an electronegativity of 2.5. how is charge distributed on an oxygen atom when it bonds with a carbon atom?
Final answer:
In a carbon-oxygen bond, oxygen, being more electronegative, pulls the bonding electrons closer, resulting in oxygen having a slight negative charge and carbon a slight positive charge, forming a polar covalent bond.
Explanation:
When a carbon atom bonds with an oxygen atom, the distribution of charge between them reflects their difference in electronegativity. Oxygen, with an electronegativity of 3.5, has a stronger pull on the bonding electron pairs than carbon, which has an electronegativity of 2.5. This results in the electrons being drawn more towards oxygen, making the oxygen atom slightly negatively charged (δ-) and the carbon atom slightly positively charged (δ+). The carbon-to-oxygen double bond, being more polar than a carbon-to-oxygen single bond, emphasizes this effect, making the oxygen even more electronegative in comparison to carbon. Therefore, in this bond, oxygen ends up with a partial negative charge, while carbon acquires a partial positive charge, exemplifying a polar covalent bond.
Select all that apply. A beta particle:
is electromagnetic energy
is an electron has zero charge
is emitted from the nucleus
has a +2 charge
has a -1 charge
A gas has a temperature of 273.15 K and a pressure of 101.325 kPa. What can be concluded about the gas?
It has reached standard temperature and pressure.
The pressure needs to be increased to reach the standard pressure.
The temperature needs to be increased to reach the standard temperature.
Both the temperature and pressure need to be lowered to reach STP.
A It has reached standard temperature and pressure.
Three treatments of different starting materials are listed. Which statement explains the treatments? Substance 1 was activated by a decrease in temperature, Substance 2 was activated by the change in concentration, and Substance 3 decreased the surface area. Substance 1 was activated by a decrease in temperature, Substance 2 was activated by the change in pressure, and Substance 3 increased the surface area. Substance 1 was activated by the heat and inactivated by ice, Substance 2 was activated by the change in pressure, and Substance 3 decreased the surface area. Substance 1 was activated by the heat and inactivated by ice, Substance 2 was activated by the change in concentration, and Substance 3 increased the surface area.
The treatment is explained by temperature in the first substance, concentration in substance 2, and surface area in substance 3. Thus, option D is accurate.
What are the factors of reaction rate?The rate of the reactions is concerned with the temperature concentration, surface area, etc. Their involvement increases and decreases the reaction rate of the substance present in the reaction mixture.
An increase in temperature by heat increases rate, and ice decreases temperature hence decreasing rate. The second substance starts with an increase in the concentration and the third by increasing surface area.
Therefore, option D. is the treatment for the substances.
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Write a detailed mechanism for the formation of ethyl acetate from ethanol and acetic acid with h2so4 as a catalyst?
Complete each nuclear fission reaction. What is A?
Answer:
143
Explanation:
Thinking process:
The equation is balanced by balancing the charges. This gives:
235 + 1 = 90 + A + 3(1)
236 = 90 + A + 3
236 = 93 + A
A = 236 - 93
= 143
therefore, the value of A is 143
How many grams of water vapor (H2O) are in a 10.2 liter sample of 0.98 atmosphere and 26 C
Given that 4 nh3 + 5 o2 → 4 no + 6 h2o, when 4.50 mol of h2o are formed, the amount of no formed is 3.00 mol.
In the chemical reaction of NH3 with O2 that produces NO and H2O, the stoichiometric ratios are used to determine that 4.5 moles of H2O production results in the formation of 3 moles of NO.
Explanation:The question is referring to a chemical reaction, specifically a stoichiometric equation. The equation shows the reaction between ammonia (NH3) and oxygen (O2) to produce nitrogen monoxide (NO) and water (H2O).
According to the stoichiometric coefficients, which are the numbers in front of the molecules, for every 6 moles of water (H2O) formed, 4 moles of nitrogen monoxide (NO) are produced. To find how much NO is produced when only 4.5 moles of H2O are formed, we need to set up a proportion: 4 NO/6 H2O = x (moles of NO)/4.5 H2O. Solving for x gives us 3 moles of NO.
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The fe2+(aq) solution described in part a was produced by dissolving 4.05 g of ore in acid. what was the percentage of fe by mass in this ore sample?
Answer:
We can't solve this problem with that data.
Explanation:
Hi! Let's solve this!
To calculate the mass percentage, use (mass of Fe / total mass of ore) * 100
In this case we have the mass of Faith but the exercise does not have enough information to calculate the percentage.
We can't solve this problem with that data.
Fill in the coefficients that will balance the following reaction: a0Na + a1H2O → a2NaOH + a3H2
Answer : The balanced chemical reaction will be,
[tex]2Na+2H_2O\rightarrow 2NaOH+H_2[/tex]
Explanation :
Balanced chemical reaction : It is defined as the number of atoms of individual elements present on reactant side must be equal to the product side.
The given unbalanced chemical reaction is,
[tex]a_0Na+a_1H_2O\rightarrow a_2NaOH+a_3H_2[/tex]
This chemical reaction is an unbalanced reaction because in this reaction, the number of atoms of hydrogen are not balanced while all the atoms are balanced.
In order to balanced the chemical reaction, the coefficient 2 is put before the [tex]Na,H_2O\text{ and }NaOH[/tex]
Thus, the balanced chemical reaction will be,
[tex]2Na+2H_2O\rightarrow 2NaOH+H_2[/tex]
Write the complete balanced equation for the following reaction: Na2SO4 + Pb(NO3)2 -->NaNO3 + PbSO4
The balanced equation for the reaction between sodium sulfate (Na₂SO₄) and lead(II) nitrate (Pb(NO₃)₂) to form sodium nitrate (NaNO₃) and lead(II) sulfate (PbSO₄) is as follows:
2 Na₂SO₄ + Pb(NO₃)₂ ⇒ 2 NaNO₃ + PbSO₄
In this equation, we balance the number of atoms on both sides of the equation. There are two sodium (Na) atoms on both sides, two sulfate (SO₄) ions on both sides, two nitrate (NO₃) ions on both sides, and one lead (Pb) atom on both sides. The equation is now balanced.
On the left-hand side of the equation, we have 2 sodium sulfate molecules and 1 lead(II) nitrate molecule.
On the right-hand side of the equation, we have 2 sodium nitrate molecules and 1 lead(II) sulfate molecule.
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Final answer:
The complete balanced chemical equation for the reaction of sodium sulfate with lead(II) nitrate to form sodium nitrate and lead(II) sulfate is Na2SO4(aq) + Pb(NO3)2(aq) → 2NaNO3(aq) + PbSO4(s).
Explanation:
The question pertains to writing a complete and balanced chemical equation for a double-replacement reaction between sodium sulfate (Na2SO4) and lead(II) nitrate (Pb(NO3)2), resulting in the formation of sodium nitrate (NaNO3) and lead(II) sulfate (PbSO4), the latter being a precipitate. To balance this reaction, we must ensure that the number of atoms of each element is the same on both sides of the equation. The balanced chemical equation, by inspection, is:
Na2SO4(aq) + Pb(NO3)2(aq) → 2NaNO3(aq) + PbSO4(s)
We now verify the balance by counting atoms:
2 sodium (Na) atoms on both sides
1 sulfate (SO4) group on both sides
1 lead (Pb) atom on both sides
2 nitrate (NO3) groups on both sides
Each element and polyatomic ion is balanced, confirming that the equation is correctly balanced.
For elements to maintain a neutral charge, which two particles must have equal numbers?
Explanation:
An atom holds three sub-atomic particles and these are protons, neutrons and electrons.
Protons have a positive charge, neutrons have no charge and electrons have a negative charge.
Also, when an atom or element is neutral in nature then it means it contains same number of protons and electrons.
For example, sodium element is a neutral atom as it contains 11 protons and 11 electrons.
Thus, we can conclude that for elements to maintain a neutral charge, protons and electrons are the two particles that must have equal numbers.
When nitrogen gas reacts with hydrogen gas to form ammonia, what is the coefficient on nitrogen in the balanced equation?
Final answer:
The coefficient on nitrogen in the balanced equation is 1.
Explanation:
When nitrogen gas reacts with hydrogen gas to form ammonia, the coefficient on nitrogen in the balanced equation is 1. The balanced chemical equation for this reaction is: 3H2 (g) + N2 (g) → 2NH3 (g). In the equilibrium constant expression, the partial pressure of nitrogen is raised to the first power due to the coefficient 1. According to Dalton's Atomic Theory, one of its postulates states that each compound is composed of a fixed ratio of the number of its individual atoms. This is where the Law of Definite Proportions is coming from. In order to obey this law, you must balance the equation such that the number of moles of each element in a reaction is equal for both sides of the reaction. Thus, the balance reaction is
N₂ + 3 H₂ → 2 NH₃
Thus, the coefficient of Nitrogen is 1.
The primary anthropogenic source of atmospheric carbon dioxide (co2 ) is
One characteristic of a scientific theory is that _______
a. it can never be proved
b. it can be proved
c. it cannot be modified
d. it summarizes a set of observations
Answer;
a. it can never be proved
Explanation;
-One characteristic of a scientific theory is that it can never be proved.
-A scientific theory is a series of statements about the causal elements for observed phenomena. It is a hypothesis or a group of hypotheses about some phenomena that have been supported through research using the scientific method.
Answer: Option (d) is the correct answer.
Explanation:
A scientific theory is the result or output of a number of experiments, research, tests, observations etc.
A scientific theory is checked and verified at each and every step in order to provide a fact to the world. Hence, a scientific theory is that it summarizes a set of observations.
On the basis of these observations, a conclusion or theory is established.
The mole fraction of hcl in a solution prepared by dissolving 5.5 g of hcl in 200 g of c2h6o is ________. the density of the solution is 0.79 g/ml.
To find the mole fraction of HCl in the solution, calculate the number of moles of HCl and C2H6O. Then, divide the moles of HCl by the total moles of all components in the solution.
Explanation:To find the mole fraction of HCl in the solution, we first need to calculate the number of moles of HCl and C2H6O in the solution. The mole fraction of a component is defined as the moles of that component divided by the total moles of all components in the solution.
First, calculate the number of moles of HCl using its mass and molar mass:
Moles of HCl = mass / molar mass = 5.5 g / 36.461 g/mol = 0.151 mol
Next, calculate the number of moles of C2H6O using its mass and molar mass:
Moles of C2H6O = mass / molar mass = 200 g / 46.07 g/mol = 4.342 mol
Finally, calculate the mole fraction of HCl:
Mole fraction of HCl = Moles of HCl / (Moles of HCl + Moles of C2H6O) = 0.151 mol / (0.151 mol + 4.342 mol) = 0.0334
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why does it take much longer for a car to stop when applying the brakes at a speed of 60 miles per hour then it 50 miles per hour
Answer: force and friction
Explanation: because its forward momentum is greater when it goes faster, therefore it requires more force/friction to slow it down to a halt.
Solar energy breaks oxygen molecules (o2) apart in the stratosphere, releasing ____, that then combine with additional oxygen molecules (0) to form ____.
What is described here is actually the formation of ozone in the atmosphere. Ozone is what makes up the ozone layer, the shield in the Earth’s atmosphere that absorb the sun’s harmful UV radiation.
Now when solar energy hits O2 molecules, this results to a release in Oxygen atoms. When these Oxygen atoms combine with O2 molecules, Ozone or O3 is formed.
The correct answers are:
Oxygen atoms
Ozone
A fatty acid with only single bonds between carbon atoms is called a(n) ________ fatty acid.
Under what conditions will a low temperature make a reaction spontaneous
Answer: if delta h and delta s are both negative
Explanation: you’re welcome
Rifampin is a nonspecific cyp450 inducer that may:
Rifampin is a nonspecific cyp450 inducer that may: inhibit bacterial transcription by blocking RNA polymerase.
This interaction is important to consider when co-administering medications.
Rifampin is a semisynthetic member of the rifamycin class that works by blocking bacterial RNA polymerase activity, thereby inhibiting transcription. This process prevents the bacteria from synthesizing mRNA, which is crucial for protein synthesis and bacterial growth.
As a nonspecific CYP450 inducer, rifampin can increase the metabolism of drugs that are substrates of the cytochrome P450 enzyme system. Consequently, this induction can reduce the effectiveness of other medications metabolized by CYP450, such as certain anticoagulants, contraceptives, and antivirals.
If a patient on rifampin is also taking an oral contraceptive pill, the effectiveness of the contraceptive can be decreased due to the enhanced metabolism caused by rifampin, leading to a higher risk of unintended pregnancy.
Which statement regarding nuclear and chemical reactions is not true?
Chemical reactions involve outer electrons.
Only chemical reactions result in atom stability.
Nuclear reactions release more energy per mole.
Nuclear reactions occur in the nucleus of the atom.
Answer: Option (b) is the correct answer.
Explanation:
A chemical reaction is a reaction that causes change in chemical composition of a substance. This change occurs due to the involvement of outer electrons.
Whereas a nuclear reaction is a reaction in which particles in the nucleus, that is, protons and neutrons participate in order to form a new compound.
For example, [tex]^{6}_{3}Li + ^{2}_{1}H \rightarrow 2^{4}_{2}He[/tex]
Both chemical and nuclear reactions are able to release energy in certain reactions and they both are able to form stable atoms.
Thus, we can conclude that the statement only chemical reactions result in atom stability regarding nuclear and chemical reactions is not true.
What is the lewis structure of the covalent compound that contains one nitrogen atom, one hydrogen atom, and one carbon atom?
The Lewis structure of the covalent compound HCN consists of a carbon atom connected to a hydrogen atom with a single bond and a nitrogen atom with a triple bond. Both carbon and nitrogen have a linear electron-pair and molecular geometry.
Explanation:The Lewis structure for a covalent compound containing one nitrogen atom, one hydrogen atom, and one carbon atom would be HCN. In the Lewis structure of HCN, carbon is the central atom, connected with a single bond to hydrogen and a triple bond to nitrogen. The nitrogen atom will have one lone pair. The Lewis structure help us visualize the distribution of valence electrons among atoms.
Here, the electron-pair geometries would be nitrogen-tetrahedral, carbon-tetrahedral, and hydrogen-linear. On the local structures, the hydrogen is linear, the carbon appears linear, and the nitrogen appears to be linear as well.
The Lewis structure of the covalent compound that contains one nitrogen atom, one hydrogen atom, and one carbon atom can be determined by following the octet rule. Nitrogen has five valence electrons, hydrogen has one, and carbon has four. The Lewis structure would look like:
N
/ \
H C
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What condition is often confused with the early stages of carbon monoxide poisoning boat ed?
What is the ph of a solution containing the strong base ba(oh)2 at a concentration of 0.064 mol/l?