Answer: The correct answer is Option E.
Explanation:
Electronegativity is the chemical property of an element. This is defined as the tendency of an atom to attract the shared pair of electrons towards itself when a bond is formed.
This property of an atom increases as we move from left to right in a period because the number of charge on the nucleus increases.
But this property decreases as we move from top to bottom in a group because electrons get added up in the new shells which make it further far away from the nucleus.
Thus, the correct answer is Option E.
The viscosity of polymers __________ as the cross-linking increases within the polymer.
A)
increases
B)
decreases
C)
multiples
D)
stays the same
The viscosity of polymers A) increases as the cross-linking increases within the polymer.
Explanation:A cross-linking increases the viscosity of the polymer. Cross-link is the bond that links properly, one polymer to other. The viscosity is highly increased because it connects the separate gel polymers together and tightly.
As cross-linker links the polymer together so the actual molecular weight of the polymer is increased, which significantly increases the viscous property of the element. Not only viscosity, the cross linking also increases the strength of the compound.
Final answer:
The viscosity of water decreases as temperature increases due to molecular interactions. Chain entanglement affects polymer viscosity, and increased cross-linking in polymers results in increased viscosity.
Explanation:
B. As temperature increases, the viscosity of water decreases due to changes in molecular interactions. When temperature rises, the kinetic energy of the water molecules increases, causing them to move faster and disrupt the intermolecular forces, leading to decreased viscosity.
Chain entanglement is another factor affecting viscosity in polymers. When polymer chains are entangled, the viscosity of the solution increases due to the resistance encountered as the chains move. However, at very high rates of shear strain, where entanglements aren't formed, viscosity doesn't increase as expected.
In the case of polymers with increased cross-linking, the viscosity will increase as the rotational motion within the polymer decreases, requiring more energy to overcome the restrictions, ultimately leading to higher transitional temperatures.
A sample of nitrogen occupies 10.0 liters at 25°c and 98.7 kpa. What would be the volume at 20°c and 102.7 kpa?
Answer:
9.4 literExplanation:
1) Data:
V₁ = 10.0 L T₁ = 25°C = 25 + 273.15 K = 298.15 K P₁ = 98.7 Kpa T₂ = 20°C = 20 + 273.15 K = 293.15 K P₂ = 102.7 KPa V₂ = ?2) Formula:
Used combined law of gases:
PV / T = constant P₁V₁ / T₁ = P₂V₂ / T₂3) Solution:
Solve the equation for V₂:
V₂ = P₁V₁ T₂ / (P₂ T₁)Substitute and compuite:
V₂ = P₁V₁ T₂ / (P₂ T₁)V₂ = 98.7 KPa × 10.0 L × 293.15 K / (102.7 KPa × 298.15 K) V₂ = 9.4 liter ← answer
You can learn more about gas law problems reading this other answer on Brainly: https://brainly.com/question/12732788.
The correct volume of the nitrogen sample at 20°C and 102.7 kPa is approximately 11.3 liters.
To solve this problem, we can use the combined gas law, which states that for a given amount of gas, the product of pressure and volume divided by the temperature is constant:
[tex]\[\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}\][/tex]
Given:
[tex]\(P_1 = 98.7\) kPa\\ \(V_1 = 10.0\) liters\\ \(T_1 = 25C + 273.15 = 298.15\) K (converted to Kelvin)\\ \(P_2 = 102.7\) kPa\\\(T_2 = 20C + 273.15 = 293.15\) K (converted to Kelvin)[/tex]
We want to find [tex]\(V_2\)[/tex], the final volume. Rearranging the combined gas law equation to solve for [tex]\(V_2\)[/tex], we get:
[tex]\[V_2 = \frac{P_1V_1T_2}{P_2T_1}\][/tex]
Substituting the given values:
[tex]\[V_2 = \frac{(98.7\text{ kPa})(10.0\text{ L})(293.15\text{ K})}{(102.7\text{ kPa})(298.15\text{ K})}\] \[V_2 = \frac{(98.7)(10.0)(293.15)}{(102.7)(298.15)}\] \[V_2 = \frac{289480.05}{306469.85}\] \[V_2 \approx 11.3\text{ L}\][/tex]
Therefore, the volume of the nitrogen sample at 20°C and 102.7 kPa is approximately 11.3 liters.
A substance has a boiling point of 78 °C. Which of the following is true about the substance?
When the substance is heated, its temperature will start rising above 78 °C after 50% of the liquid has changed to vapors.
When the substance is heated, its temperature will start rising above 78 °C after 100% of the solid has changed to liquid.
When the substance is cooled, its temperature will fall below 78 °C after 100% of the vapor has changed to liquid.
When the substance is cooled, its temperature will fall below 78 °C after 50% of the liquid has changed to solid.
Answer:
When the substance is cooled, its temperature will fall below 78 °C after 100% of the vapor has changed to liquid.
Explanation:
Boiling point is the temperature at which a liquid changes state from liquid form to gaseous form without change in temperature. It may defined as the temperature at which the vapor pressure is equal to the pressure of the gas above the liquid.A liquid with a boiling point of 78°C, it means that, when the liquid is heated, its temperature will start rising above 78 °C after 100% of the liquid has changed to vapors. Additionally, when the liquid is cooled, its temperature will fall below 78 °C after 100% of the vapor has changed to liquid.The accurate statement is that the temperature of a substance with a boiling point of 78 0C will fall below this temperature once all the vapor has condensed into liquid, as the phase change maintains the boiling point until the transition is complete.
The statement about a substance with a boiling point of 78 0C that is true is: When the substance is cooled, its temperature will fall below 78 0C after 100% of the vapor has changed to liquid. At the boiling point, a substance undergoes a phase change from liquid to vapor, and it remains at this temperature until the liquid has fully transitioned into vapor. Therefore, the temperature won't rise above the boiling point until all the liquid has become vapor. Conversely, when cooling, the temperature will not drop below the boiling point until all vapor has condensed back to liquid.
This is due to the energy being used to facilitate the change of state rather than altering temperature. Similarly, when a substance is melting or freezing, the temperature remains constant at the melting point until the transition between solid and liquid is complete.
Do steps 3 as outlined in the lab guide. Record your results in the appropriate blanks
A=
B=
c=
D=
E=
F=
G=
H=
A= 56
B= 27
c= 12
D= 8
E= 3
F= 3
G= 1
H= 1
is what the edg. example shows but any answers are accepted!!
Some tips to follow when doing lab practicals are:
Avoid parallax errorsRecord your observations and data accuratelyUse the appropriate lab equipment.What is a Lab Practical?This refers to the systematic research that is done in a scientific process in a controlled environment to test or prove a hypothesis.
Hence, we can see that your question is incomplete because it does not show the radioactive atoms and their data from the given lab work, hence a general overview is given for better understanding.
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A chemical symbol represents the ____ of an element
A chemical symbol represents the shorthand of an element. It is a one- or two-letter abbreviation that is used to represent an element in chemical formulas and equations.
What are chemical symbol?The first letter of the symbol is always capitalized, and the second letter is lowercase, if there is a second letter. For example, the chemical symbol for hydrogen is H, the chemical symbol for oxygen is O, and the chemical symbol for carbon is C.
Chemical symbols are derived from the Latin names of the elements. For example, the chemical symbol for hydrogen is derived from the Latin word "hydrogenium," which means "water-former."
Chemical symbols are an important part of chemistry because they allow chemists to communicate with each other easily. They also help to simplify chemical formulas and equations, making them easier to understand.
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A chemical symbol is a one- or two-letter designation that represents an element's name, used for single atoms or larger quantities.
A chemical symbol represents the name of an element. It is a one- or two-letter abbreviation that signifies a single atom of an element (microscopic domain) or a collection of atoms within a sample of that element (macroscopic domain). For instance, the chemical symbol for mercury is 'Hg'. Many chemical symbols are derived from their English names, with the initial letter capitalized and any subsequent letter in lower case. For example, 'O' represents oxygen, 'Zn' represents zinc, and 'Fe' represents iron. Certain elements, particularly those known since ancient times, retain symbols based on their Latin names. Chemical symbols are also used to create chemical formulas that show the types and numbers of atoms in a molecule of a compound.
Which half-reaction correctly represents reduction?
A) Ag -> Ag+ + e–
B) F2 -> 2 F– + 2e–
C) Au3+ + 3e– -> Au
D) Fe2+ + e– -> Fe3+
The half-reaction that is correctly represents reduction is Au₃⁺ + 3e– -> Au. The correct option is C.
What is half-reactions?
The half-reaction is an oxidation and reduction reaction of a redox reaction. It can be either oxidation or reduction. The half-reaction occurs due to change in oxidation state of a reactant.
An example is Zn Cu galvanic cell.
Thus, the correct option is C) Au3+ + 3e– -> Au.
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shanice and jenny each improved their yards by planting grass sod and ornamental grass. they bought their supplies from the same store. shanice spent $280 on 14 feet of grass sod and 14 bunches of ornamental grass. jenny spent $251 on 12 ft of grass sod and 13 bunches of ornamental grass find the cost of one ft of grass sod and the cost of one bunch of ornamental grass.
Answer:
$10 per foot and per bunch of ornamental grass
Explanation:
1.) What coefficient values will balance the reaction shown? CH4 + O2 ?CO2 + H2O
A.1,1,1,1
B.1,2,1,2
C.2,1,2,1
D.1,1,2,1
2.) Which is a balanced equation for this reaction?
A.KOH + H3PO4?K3PO4 + H2O
B.3KOH + H3PO4 ?K3PO4 + 3H2O
C.KOH + 2H3PO4?K3PO4 + 3H2O
D.3KOH + 2H3PO4?K3PO4 + 3H2O
3.) Which is a balanced equation for this reaction?A.NH3 + O2?NO + H2O
B.4NH3 + O2?2NO + 3H2O
C.2NH3 + O2?2NO + 3H2O
D.4NH3 + 5O2?4NO + 6H2O
4.) Which is a balanced equation for this reaction?A.B2Br6 + 6HNO3?2B(NO3)3 + 6HBr
B.B2Br6 + 3HNO3?B(NO3)3 + 3HBr
C.B2Br6 + 2HNO3?2B(NO3)3 + 6HBr
D.B2Br6 + 2HNO3?2B(NO3)3 + 3HBr
5.) Balance the equation by calculating the coefficients. P4 + O2?P2O5
A.1,5,2
B.1,1,2
C.1,5,1
D.1,2,3
Answer:
It's simpler than most questions :)
Explanation:
1) B
2) B
3) D
4) A
5) A
Hope this will help :)
Calculate the boiling point of a 2.00 molal solution of magnesium perchlorate, mg(clo4)2, in water.
Answer:
103.06°C.
Explanation:
To solve this problem, we can use the relation:ΔTb = i.Kb.m,
Where, i is the van 't Hoff factor.
Kb is the molal boiling point elevation constant of water (Kb = 0.51°C/m).
m is the molality of the solution (m = 2.0 m).
We need to define and find the van 't Hoff factor (i):van 't Hoff factor is the ratio between the actual concentration of particles produced when the substance is dissolved and the concentration of a substance as calculated from its mass.
Mg(ClO₄)₂ is dissociated according to the equation:Mg(ClO₄)₂ → Mg²⁺ + 2ClO₄⁻,
1 mol of Mg(ClO₄)₂ produces 3 mol of ions (1 mol Mg²⁺ and 2 mol ClO₄⁻).
∴ i = 3/1 = 3.
∴ ΔTb = i.Kb.m = (3)(0.51 °C/m)(2.0 m) = 3.06 °C.
∵ ΔTb = the boiling point in presence of solute (Mg(ClO₄)₂) - the boiling point of pure water.
The boiling point of pure water = 100.0°C.
∴ The boiling point in presence of solute (Mg(ClO₄)₂) = ΔTb + the boiling point of pure water = 3.06 °C + 100.0°C = 103.06°C.
The boiling point of a 2.00 molal magnesium perchlorate solution is calculated to be 103.06°C by determining the van't Hoff factor and using the molal boiling point elevation constant for water.
Explanation:To calculate the boiling point of a 2.00 molal solution of magnesium perchlorate, Mg(ClO₄)₂, we first need to determine the van't Hoff factor (i), which is the number of particles the compound dissociates into in solution. Magnesium perchlorate dissociates into one Mg²⁺ ion and two ClO₄⁻ ions, giving us an i value of 3. We use the molal boiling point elevation constant (Kb) for water and the molality of the solution (m) to find the boiling point elevation (ΔTb).
Since Kb for water is typically given as 0.51°C/m, the boiling point elevation can be calculated using the formula: ΔTb = i * Kb * m. Given that the solution is 2.00 molal, the boiling point elevation is:
ΔTb = 3 * 0.51°C/m * 2.00 m = 3.06°C
To find the final boiling point, you add the boiling point elevation to the normal boiling point of water, which is 100°C:
Boiling point = 100°C + 3.06°C = 103.06°C
Therefore, the boiling point of the 2.00 molal magnesium perchlorate solution is 103.06°C.
How many electrons in an atom can share the quantum numbers n = 4 and l = 3?
Answer:
[tex]\boxed{\text{14}}[/tex]
Explanation:
If l = 3, the electrons are in an f subshell.
The number of orbitals with a quantum number l is 2l + 1, so there
are 2×3 + 1 = 7 f orbitals.
Each orbital can hold two electrons, so the f subshell can hold 14 electrons.
[tex]\boxed{\textbf{14 electrons}} \text{ can share the quantum numbers n = 4 and l = 3.}[/tex]
Here we want to find the number of electrons that an atom can have for some given quantum numbers.
We will see that this atom can hold 14 electrons.
Now let's see how to get that answer:
We know that for an atom with quantum numbers n and l, the orbitals can take the values from -l to l, so we will have 2*l + 1 orbitals.
And in each one of these orbitals, we can hold a maximum of two electrons (one for each spin, remember that these are fermions, thus we can't have two of them in the same state, so we can't have two electrons in the same orbital with the same spin, this is why each orbital can hold a maximum of two electrons).
Then the number of electrons that an atom with quantum numbers n and n can hold is:
2*(2*l + 1).
Now we have.
n = 4
l = 3
Then the number of electrons that this atom can hold is:
e = 2*(2*3 + 1) = 2*7 = 14
This atom can hold 14 electrons.
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Given 132.8J of energy is required to heat 11.17g of aluminum from 15.73°C to 28.94°C find the specific heat of aluminum.
Answer:
0.9 J/g.°C.
Explanation:
To solve this problem, we can use the relation:Q = m.c.ΔT,
where, Q is the amount of energy (Q = 132.8 J).
m is the mass of Al (m = 11.17 g).
c is the specific heat capacity of Al (c of Al = ??? J/g.°C).
ΔT is the difference between the initial and final temperature (ΔT = final T - initial T = 28.94°C - 15.73°C = 13.21°C).
∵ Q = m.c.ΔT
∴ (132.8 J) = (11.17 g)(c)(13.21°C).
∴ c = (132.8 J)/(11.17 g)(13.21°C) = 0.9 J/g.°C.
To find the specific heat of aluminum, we use the formula of heat transfer Q = mcΔT where Q is heat (132.8 J), m is mass (11.17g), ΔT is the change in temperature (13.21°C). Solving this provides the value of the specific heat of aluminum.
Explanation:The specific heat of aluminum can be calculated using the equation for heat transfer: Q = mcΔT, where Q is the heat supplied, m is the mass of the substance, c is the specific heat capacity, and ΔT is the change in temperature.
In this problem, the values are given as Q = 132.8 J, m = 11.17 g, ΔT = 28.94°C - 15.73°C = 13.21°C.
Substituting the values, we get 132.8 J = 11.17g * c * 13.21°C. To find the specific heat (c), you rearrange the equation so c = Q / (m * ΔT) = 132.8 J / (11.17g * 13.21°C).
Therefore, by solving this the value of c (specific heat of aluminum) can be calculated.
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[OSS.03]The models below represent nuclear reactions. The atoms on the left of the equal sign are present before the reaction and the atoms on the right of the equal sign are produced after the reaction.Model 1: Atom 1 + Atom 2 = Atom 3 + energyModel 2: Atom 4 = Atom 5 + Atom 6 + energyWhich of these statements is most likely correct about the two models?Both models show reactions which use up energy in the sun.Both models show reactions which produce energy in the sun.Model 1 shows reactions in the sun and Model 2 shows reactions in the nuclear power plants.Model 1 shows reactions in the nuclear power plants and Model 2 shows reactions in the sun.
Answer:
Third choice: Model 1 shows reactions in the sun and Model 2 shows reactions in the nuclear power plants.Explanation:
There are two kind of nuclear ractions: fusion and fission reactions.
Both release a huge amount of energy in different ways.
Fusion reactions are nuclear reations in which two smaller (lighter) atoms combine into a larger (heavier) atom, with the respective release of energy.
That is what model 1 shows:
Model 1: Atom 1 + Atom 2 = Atom 3 + energyThat is the process that happens and is responsible for the huge amount of heat produced in and released by the Sun.
In the Sun two atoms of hydrogen fuse into a larger atom of helium.
That is represented by the nuclear reaction:
[tex]4^1_1H[/tex] → [tex]^4_2He+{energy}[/tex] + some other particlesSince fusion reactions need extremely high temperatures and pressure to start and keep going, the technology to use them economically is still in development.
Fission reactions involve the split of the atom into smaller (lighter) atoms, releasing a huge amount of energy.
That is depicted by the model 2:
Model 2: Atom 4 = Atom 5 + Atom 6 + energyAs you see one atom is being splited in two atoms with release of energy.
And indeed, that is the technology used by the nuclear power plants.
An example is the fission of uranium-235
[tex]^{235}U+^1_0n[/tex] → [tex]^{95}Sr+^{139}Xe+2^1_0n+{energy}[/tex]Answer:
c. Model 1 shows reactions in the sun and Model 2 shows reactions in the nuclear power plants is correct
Explanation:
I got it right :)
Carbon-11 is used in medical imaging. The half-life of this radioisotope is 20.4 min. What percentage of a sample remains after 60.0 min?34.013.05.2871.22.94
The half-life of Carbon-11 is 20.4 minutes, meaning the quantity reduces by half every 20.4 minutes. So, after approximately 60.0 minutes (roughly three half-lives), approximately 12.5% of the original sample would remain.
Explanation:Carbon-11 is a radioisotope that's widely used in medical imaging due to its radioactive properties. It has a half-life of 20.4 minutes, which means that the quantity of Carbon-11 reduces to half in every 20.4 minutes.
If we denote one half-life as t, after three half-lives (60.0 min or 3t), the ratio of the remaining sample of Carbon-11 would be 1/2 * 1/2 * 1/2 = 1/8. In other words, approximately 12.5% of the original sample would be remaining. This percentage changes a bit due to the fact that 20.4 min is slightly less than 22.2 min (which would be the exact 3 half lives).
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The central atom's number of valence electrons in __________ makes it an exception to the octet rule. nh3 sef2 bf3 asf3 cf4
Answer:
[tex]\boxed{\text{BF}_{3}}[/tex]
Explanation:
You must draw the Lewis structure for each molecule, trying to give every atom an octet.
In the structures below, every molecule except one has a central atom with octet. That molecule is
[tex]\boxed{\textbf{BF}_{3}}[/tex]
The B atom has only six electrons in its valence shell, so it violates the octet rule.
BF3 (Boron Trifluoride) does not comply with the octet rule since the Boron atom has only 3 valence electrons. Nonetheless, it's a common and stable exception.
Explanation:The central atom in BF3 (Boron Trifluoride) makes it an exception to the octet rule. This is due to the fact that boron has only 3 valence electrons which results in having less than 8 electrons around the central Boron atom after bond formation. As a result, the molecule does not comply with the octet rule. However, it is a common exception and this molecule is quite stable in its normal state.
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How many grams of magnesium chloride are in 1.33 mol of MgCl2?
Answer:
126.63 g.
Explanation:
Knowing that the no. of moles can be calculated using the relation:no. of moles (n) = mass/molar mass
no. of moles MgCl₂= 1.33 mol & molar mass of MgCl₂ = 95.211 g/mol.
∴ mass = no. of moles * molar mass = (1.33 mol)*(95.211 g/mol) = 126.63 g.
Acetylene gas, c2h2 is used for welding. a 5 liter supply of acetylene being stored at -23 °c, exerts a pressure of 5 atm. at what temperature would the same number of moles of acetylene, moved to a 10 liter container, produce a pressure of 2 atm
Answer:
T₂(°C) = 200 K = - 73°C.
Explanation:
We can use the general law of ideal gas: PV = nRT.where, P is the pressure of the gas in atm.
V is the volume of the gas in L.
n is the no. of moles of the gas in mol.
R is the general gas constant,
T is the temperature of the gas in K.
If n is constant, and have different values of P, V and T:(P₁V₁T₂) = (P₂V₂T₁)
Knowing that:
P₁ = 5.0 atm, V₁ = 5.0 L, T₁ = -23°C + 273 = 250 K,
P₂ = 2.0 atm, V₂ = 10.0 L, T₂ = ??? K,
Applying in the above equation(P₁V₁T₂) = (P₂V₂T₁)
∴ T₂ = (P₂V₂T₁)/(P₁V₁) = (2.0 atm)(10.0 L)(250 K)/(5.0 atm)(5.0 L) = 200 K.
∴ T₂(°C) = 200 K - 273 = - 73°C.
The temperature at which the same number of moles of acetylene gas will produce a pressure of 2 atm in a 10-liter container is approximately -73.15°C.
Based on the given data, initially, the acetylene gas is stored at -23°C (which is 250.15 K), in a 5-liter container, exerting a pressure of 5 atm.
Step-by-Step Solution:
1. Using the combined gas laws, the formula is:
(P₁ * V₁) / T₁ = (P₂ * V₂) / T₂2. Substitute the known values into the formula:
(5 atm * 5 L) / 250.15 K = (2 atm * 10 L) / T₂3. Simplify and solve for T₂:
T₂ = (2 atm * 10 L) * 250.15 K / (5 atm * 5 L)T₂ = 10000 / (25)T₂ = 200 K4. Convert the temperature back to Celsius:
T₂ = 200 K - 273.15T₂ ≈ -73.15°CA sealed, insulated calorimeter contains water at 310 K. The surrounding air temperature is 298 K, and the water inside the calorimeter remains at 310 K two hours later. What type of system does the calorimeter attempt to model?
A closed system, because energy can enter or leave the system, but matter cannot.
A closed system, because neither heat nor matter is entering or leaving the container.
An isolated system, because energy can enter or leave the system, but matter cannot.
An isolated system, because neither heat nor matter is entering or leaving the container.
Answer:
An isolated system, because neither heat nor matter is entering or leaving the container.
Explanation:
In a closed system there is no exchange of heat but matter is exchanged. In an isolated system there is no exchange of heat or matter. Here the temperature of water remains constant at 310 K, which means that no heat is exchanged. Also there is no decreases in volume of water the calorimeter after 2 hours, which means that no matter was lost either. Therefore this is an isolated system.
2C3H7OH(l) + 9O2(g) → 8H2O(g) + 6CO2(g)
The combustion of isopropanol, i.e. rubbing alcohol, releases 1,830 kJ/mol.
Given that the molecular weight of isopropanol is 60.096 g/mol, calculate the enthalpy of combustion for 45.0g of isopropanol.
A)
147 kJ
B)
1,370 kJ
C)
2,160 kJ
D)
4,950 kJ
Answer:
B) 1,370 kJ.
Explanation:
For the reaction:2C₃H₇OH(l) + 9O₂(g) → 8H₂O(g) + 6CO₂(g) , ΔH = - 1,830 kJ/mol.
Firstly, we need to calculate the no. of moles of 45.0 g of isopropanol:
n = mass/molar mass = (45.0 g)/(60.096 g/mol) = 0.7488 mol.
Using cross multiplication:1.0 mol of isopropanol releases → 1,830 kJ.
∴ 0.7488 mol of isopropanol releases → ??? kJ.
∴ The enthalpy of combustion for 45.0g of isopropanol = (0.7488 mol)(1830 kJ)/(1.0 mol) = 1370 kJ.
So, the right choice: B) 1,370 kJ.
The enthalpy of combustion for 45.0 g of isopropanol is calculated to be 1,370 kJ by determining the number of moles and multiplying by the enthalpy of combustion per mole.So,option B is correct.
The enthalpy of combustion for 45.0 g of isopropanol, given that the combustion of isopropanol releases 1,830 kJ/mol and its molecular weight is 60.096 g/mol.
To find the enthalpy of combustion for 45.0 g of isopropanol, we should first determine the number of moles present in 45.0 g of isopropanol. This is done by dividing the mass of isopropanol by its molar mass:
Number of moles = mass (g) / molar mass (g/mol) = 45.0 g / 60.096 g/mol = 0.749 moles
Since the enthalpy of combustion of isopropanol is given per mole, we multiply the number of moles by the enthalpy of combustion:
Enthalpy of combustion = number of moles times enthalpy per mole = 0.749 moles times 1,830 kJ/mol
Therefore, the enthalpy of combustion for 45.0 g of isopropanol is:
(0.749 moles) times (1,830 kJ/mol) = 1,370 kJ
So, the correct answer is B) 1,370 kJ.
** will mark you brainliest **
When 0.5 g of powdered iron (III) oxide was added to 100 cm3 of hydrogen peroxide, water and oxygen were produced. Iron (III) oxide was not used up in the reaction. Based on the information, which of the following is likely to increase the rate formation of the products?
A. Replacing the powdered iron oxide with its cubical crystals
B. Using 150 cm3 of hydrogen peroxide
C. Removing iron oxide from the reaction mixture
D. Using 1.0 gram of iron oxide
Its B. Using 150 cm3 of hydrogen peroxide
The answer is B because when you calculate it you will get the same amount of hydrogen peroxide.
Good luck,!
The condensation of water has a negative δh and a negative δs. what can you conclude about the spontaneity of the process? view available hint(s) the condensation of water has a negative and a negative . what can you conclude about the spontaneity of the process? spontaneous at low temperatures. spontaneous at all temperatures. spontaneous at high temperatures. nonspontaneous at all temperatures
Answer:
H S G spon/ non spont
- + - spont at all Temperature
+ - + non spont at all Temperature
- - - at low tenmperature spont
+ + - at high Temperature spont
For condensation to take place there should be noticeable difference between the temperature of the system and the atmosphere. The correct option is option A.
What is condensation?Condensation is a process in which the vapor state converts to liquid state. Condensation is the reverse process of evaporation. Condensation occur at dew point. Dew point is the temperature at which condensation starts.
To see the spontaneity of a reaction following reaction should be taken into consideration
ΔG=ΔH-TΔS
the value of ΔH and ΔS are given in negative. So for condensation to be spontaneous, ΔG should be negative and for this the value of ΔH must be more negative than the value of ΔS and this happens at low temperature.
ΔH ΔS ΔG spontaneous/ non spontaneous
- + - spontaneous at all Temperature
+ - + non spontaneous at all Temperature
- - - at low temperature spontaneous
+ + - at high Temperature spontaneous
Therefore, the correct option is option A.
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1. Criminal profiling assigns crimes as one of two kinds. If a criminal profiler was looking at a case that involved a sophisticated crime ring that was responsible for a string of high-end robberies over the course of two decades, which type of crimes would these be classified as?
Forensic
Behavioral
Organized
Disorganized
2. Profilers are trained that certain psychological disorders tend to arise and peak during certain decades of life.
True
False
Answer:
So, for 1 I am most certain it has to be Organized so C. And for 2 that would be true if my brain isn't failing me- I hope this helps!
Explanation:
Answer: 1. Organized
2. True
Explanation:
1. An organized crime can be define as the crime which is committed by planning. In this crime generally the group of criminals or criminal uses same modus operandi (habit, planning, rule to commit crime).
The given example of crimes is the organized crime. This is because a sophisticated crime ring was found associated with many robberies. Hence, this can be said that similar modus-operandi is involved.
2. The profilers are those who are occupational criminals. They are trained with the fact that psychological disorders so as to defend themselves when they are caught red handed while committing crimes. They pose an evidence of their unstable or unsound mind.
Give the number of covalent bonds that a carbon atom can form.
Answer:
four covalent bonds
Explanation:
A carbon atom would form 4 covalent bonds.
For a covalent bond to be formed, an atom would share its valence electrons with another. In this process, each atom would require unpaired electrons for this bond to be formed. The number of available unpaired electrons would represent the number of electrons needed to complete the outer energy level of the atom.
In a carbon atom, we have no lone pair of electrons and 4 unpaired electrons. When these 4 electrons are shared with those of other atoms, they produce a complete octet which perfectly mimics the noble gases.
BaCl2(aq) + Na2SO4(aq) ⇄ 2NaCl(aq) + BaSO4(s)
Consider the chemical reaction represented above. What will be the resulting change if more barium chloride is added to the system?
A) There will be no change.
B) The equilibrium will change in both directions.
C) The equilibrium will shift to the left and the precipitate will dissolve.
D) The equilibrium will shift to the right and more precipitate will be formed.
Answer:
D) The equilibrium will shift to the right and more precipitate will be formed.
Explanation:
Le Châtelier's principle states that when there is an dynamic equilibrium, and this equilibrium is disturbed by an external factor, the equilibrium will be shifted in the direction that can cancel the effect of the external factor to reattain the equilibrium.For the reaction:BaCl₂(aq) + Na₂SO₄(aq) ⇄ 2NaCl(aq) + BaSO₄(s)↓,
Adding more BaCl₂ to the system:
will increase the concentration of BaCl₂ (reactants), so the equilibrium will be shifted to the right side (products side) to suppress the effect of increasing the BaCl₂.
So, the right choice is:D) The equilibrium will shift to the right and more precipitate will be formed.
Some students performed a titration between 20.0 mL of 0.5 M hydrochloric acid and 1.0 M potassium hydroxide solution. The students collected data and plotted the graph below. Which statement correctly explains the reaction at point D?
OPTION A) All hydroxide ions have reacted. There is no excess of hydroxide ions at this point.
OPTION B) The volume of base that has been added is equal to the volume of acid in the flask; this helps in balancing the ions present, making the pH of the solution neutral.
OPTION C) All hydrogen ions and all hydroxide ions have reacted to produce water, and so neither ion remains free in solution.
OPTION D) There are extra hydrogen ions in solution. As the base is added, the pH increases exponentially.
Answer:
OPTION C) All hydrogen ions and all hydroxide ions have reacted to produce water, and so neither ion remains free in solution.
Explanation:
The PH reading on the left axis of the graph shows a value of 7.
A value of 7 on the PH scale implies that equal number of hydrogen ions completely reacted with hydroxyl ions to produce water i.e there is no excess of hydrogen and hydroxyl ion remaining in solution.
For values greater than 7, a basic solution is formed and it signifies the presence of excess hydroxyl ion. If the value is less than 7, there is more hydrogen ions in the solution formed and it is said to be acidic.
At point 7, the hydrogen and hydroxyl ions are equal and completely neutralize out one another.
Note: The acid solution would require a base volume of 20mL to be completely neutralized according to the plot. If it is less, the PH shifts to the left and the solution becomes acidic. If it more, the solution becomes basic and the PH shifts rightwards.
C on e 2020
extra words for 20 letters
What happens to the average kinetic energy of the particles in a sample of matter as the temperature of the sample is increased?
Answer:
As the temperature of a sample of matter is increased, the average kinetic energy of the particles in the sample increase.Explanation:
The temperature of a substance is the measure of the average kinetic energy of its partilces.
The temperature, i.e. how hot or cold is a substance, is the result of the collisions of the particles (atoms or molecules) of matter.
The kinetic theory of gases states that, if the temperature is the same, the average kinetic energy of any gas is the same, regardless the gas and other conditions.
This equation expresses it:
Avg KE = (3/2) (R / N) TWhere Avg KE is the average kinetic energy, R is the universal constant of gases, N is Avogadro's constnat, and T is the temperature measure in absolute scale (Kelvin).
As you see, in that equation Avg KE is propotional to T, which means that as the temperature is increased, the average kinetic energy increases.
As the temperature of a sample of matter is increased, the average kinetic energy of the particles also increases. This is because higher temperatures result in more extensive vibrations of particles in solids and faster translations of particles in liquids and gases. The distribution of kinetic energies also becomes broader at higher temperatures, indicating an increase in entropy.
Explanation:According to kinetic-molecular theory, the temperature of a substance is proportional to the average kinetic energy of its particles. Raising the temperature of a substance will result in more extensive vibrations of the particles in solids and more rapid translations of the particles in liquids and gases.
At higher temperatures, the distribution of kinetic energies among the atoms or molecules of the substance is also broader (more dispersed) than at lower temperatures. Thus, the entropy of any substance increases with temperature.
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"a sample of helium gas at 27.0 °c and 4.20 atm pressure is cooled in the same container to a temperature of -73.0 °c. what is the new pressure?"
Answer: 2.80 Atm
Explanation:
Gay-lussac's law
P1÷T1=P2÷T2
T2·P1÷T1
(200)·(4.20)÷300
A covalent bond is formed as the result of
Answer:
A covalent bond is formed as the result of sharing electrons.Explanation:
There are three kind of chemical bonds: covalent, ionic, and metallic.
The chemical bonds are the result of the interaction of the valence electrons of the atoms.
The valence electrons may be:
Donated / accepted: an atom donates one or more electrons which are taken by one or more other atoms. In this case, the atom that donates electrons becomes a positve ion (cation) and the atom that takes electrons becomes a negative ion (anion). Then, as positive and negative charges are attracted to each other, a strong electrostatic attraction arises between cations and anions, and this is what is called an ionic bond.Shared between a pair of atoms: in this case, none of the atoms gets rid of any electron, instead, to complete the valence electron shell (octet rule) both atoms share some electrons. In this case, each pair of shared electrons is a covalent bond.Thus, this is the answer to your question: a covalent bond is formed as the result of sharing electrons.
Delocalised: metals posses a number of delocalised electrons, i.e. electrons that are losely attached to their nuclei, and so these electrons are shared by a number of atoms. The bond formed is called metallic bond, is depicted as a sea of electrons, because many electrons are moving freeely among many atoms.A covalent bond is a type of chemical bond that forms when atoms share electrons to complete their valence shells, thereby creating an attractive force between atoms. These types of bonds can be nonpolar when electrons are shared equally, or polar when there's an imbalance in sharing. An example of covalent bonding is seen in the formation of a water molecule.
Explanation:A covalent bond is a type of strong chemical bond that is formed between two atoms of the same or different elements. This bond occurs when atoms share electrons in order to complete their valence shells or the outermost shell of an atom that contains its most reactive electrons. This sharing of electrons is an attractive force between the nuclei of a molecule's atoms and pairs of electrons between the atoms. There are various types of covalent bonds. When the sharing of electrons between atoms is equal, the bond is considered nonpolar. However, when electrons are not equally shared due to differences in electronegativity, the bond is said to be polar.
An example of covalent bonding is the formation of a water molecule where hydrogen and oxygen atoms combine and are bound together by covalent bonds. The electrons from the hydrogen split their time between the incomplete outer shell of the hydrogen atoms and the incomplete outer shell of the oxygen atoms. In order to completely fill the outer shell of oxygen, which has six electrons but would be more stable with eight, it requires two electrons (one from each hydrogen atom). Thus, it results in the well-known formula H2O where electrons are shared between the two elements to completely fill the outer shell of each, making both more stable.
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A solution of 20.0 g of which hydrated salt dissolved in 200 g H2O will have the lowest freezing point?(A) CuSO4•5H2O(M=250)(B) NiSO4•6H2O(M=263)(C) MgSO4•7H2O(M=246)(D) Na2SO4 • 10 H2O (M = 286)
Answer:
The solution of Na₂SO₄ . 10H₂O ( choice D), will have the lowest freezing point.Explanation:
1) The lowering of the freezing point is a colligative property which means that it depends, and can be calculated from some contants of the pure solvent, and the number of solute particles dissolved.
ΔTf = m × Kf × iWhere, ΔTf is the reduction in the freezing point, m is the molality of the solution, Kf is the cryoscopic constant of the solvent, and i is the Van't Hoff factor.
2) Find the molality of each solution, m:
Formulae:moles of solute, n = mass in grams / molar mass
m = n / kg of solvent
(A) CuSO₄•5H₂O (M=250)
n = 20.0 g / 250 g/mol = 0.0800 molm = 0.0800 mol / 0.200 kg = 0.400 m(B) NiSO₄•6H₂O(M=263)
n = 20.0 g / 263 g/mol = 0.0760 molm = 0.0760 mol / 0.200 kg = 0.380 m(C) MgSO₄•7H₂O (M=246)
n = 20.0 g / 246 g/mol = 0.0813 molm = 0.0813 mol / 0.200 kg = 0.406 m(D) Na₂SO₄ • 10 H₂O (M = 286)
n = 20.0 g / 286 g/mol = 0.0699 molm = 0.0699 mol / 0.200 kg = 0.350 m3) Van't Hoff factor.
Since, all the solutes are ionic, you start assuming that they all dissociate 100%.
That means that:
Each unit of CuSO₄.5H₂O yields 2 ions in water ⇒ i = 2Each unit of NiSO₄. 6H₂O yileds 2 ions in water ⇒ i = 2Each unit of MgSO₄.7H₂O yields 2 ions in water ⇒ i = 2Each unit of Na₂SO₄.10H₂O yields 3 ions in water ⇒ i = 34) Comparison
Being Kf a constant for the four solutions (same solvent), you just must compare the product m × i
CuSO₄.5H₂O: 2 × 0.400 = 0.800NiSO₄. 6H₂O: 2 × 0.380 = 0.760MgSO₄.7H₂O: 2 × 0.406 = 0.812Na₂SO₄.10H₂O: 3 × 0.406 = 1.218As you see from above calculations, the dissociation factor defines the situation, and you can conclude that the last choice, i.e. the solution of Na₂SO₄ . 10H₂O, will have the greatest decrease of the freezing point, resulting in the lowest freezing point.
A bunch of amino acids attached together is called a
Answer:
They join together to form short polymer chains called peptides or longer chains called either polypeptides or proteins.
Explanation:
A bunch of amino acids attached together is called a protein.
Explanation:Proteins are complex macromolecules essential for various biological functions. They consist of amino acids linked together through peptide bonds. Amino acids, the building blocks of proteins, have distinct structures and properties. The specific sequence and arrangement of these amino acids in a protein dictate its unique function.
Proteins play crucial roles in the body, including enzymes that catalyze chemical reactions, structural components like collagen, and antibodies that defend against pathogens. They also serve as hormones, transport molecules, and provide mechanical support. The diversity of proteins and their functions underpins the complexity of life processes, making them fundamental to all living organisms.
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You have a solution of sugar in water.You want to obtain the sugar from it.A:explain why filtration will not work ,b:which method will you use instead?
Filtration will not work because sugar dissolves in water. Instead, you’ll need to boil the water into steam to isolate the sugar
Filtration is a method that is used to separate insoluble solids from a liquid. Since salt and sugar both dissolve in water, filtration cannot be used to separate the two. When sugar is mixed with water it creates a homogeneous solution, meaning you can't see the individual particles, unlike when you mix sand with water. The sugar water is a solution because no chemical reaction occurs, but to separate it you need to create a chemical reaction by distilling the liquid.