Question 1

Reaction rates are determined by all of the following factors except

Accepted Answer

A) the number of collisions between molecules. 
B) the force of collisions between molecules. 
C) the orientation of collisions between molecules. 
D) the spontaneity of the reaction. 
E) the activation energy of the reaction.

Question 2

Select the correct figure to match the description.
-A fast reaction with a large negative free energy change

Accepted Answer

A)  
B)  
C)  
D)  
E)

Question 3

Which change to this reaction system would cause the equilibrium to shift to the right?
N2 (g)+ 3 H2 (g) 
2 NH3 (g)+ heat

Accepted Answer

A) addition of a catalyst 
B) addition of NH3 (g) 
C) removal of H2 (g) 
D) heating the system 
E) lowering the temperature

Question 4

In the reaction A + B → AB,which of the following will not increase the rate?

Accepted Answer

A) adding A 
B) adding B 
C) increasing the temperature 
D) decreasing the temperature 
E) adding a catalyst

Question 5

All of the statements concerning free energy and spontaneity are true except

Accepted Answer

A) if the value of ΔG for a reaction is 55.2 kcal,the value of ΔG for the reverse reaction will be -55.2 kcal. 
B) if the value of ΔG for a reaction is negative,the reaction is said to be spontaneous. 
C) a reaction which is nonspontaneous at low temperature cannot be spontaneous at higher temperatures. 
D) enthalpy and entropy are of equal importance in determining the spontaneity of a reaction. 
E) the speed of a reaction is not influenced by its spontaneity.

Question 6

Consider the reaction shown:
2 CO (g)+ O2 (g)→ CO2 (g)+ 135.2 kcal
This reaction is ________ because the sign of ΔH is ________.

Accepted Answer

A) endothermic; positive 
B) exothermic; positive 
C) endothermic; negative 
D) exothermic; negative 
E) exothermic; neither positive nor negative

Question 7

Which factors would increase the rate of a chemical reaction?
I.Increasing the temperature
II.Removing products as they are formed
III.Adding a catalyst

Accepted Answer

A) I and II 
B) II and III 
C) I,II,and III 
D) I only 
E) II only

Question 8

4 PCl3 (l)→ P4 (s)+ 6 Cl2 (g) ΔH = 304.0 kcal
Based on the reaction shown,which statement is true?

Accepted Answer

A) When 1 mol PCl3 (l)reacts,304.0 kcal are released. 
B) When 1 mol P4 (s)is produced,304.0 kcal are consumed. 
C) When 548.56 g PCl3 (l)react,304.0 kcal are released. 
D) When 137.14 g PCl3 (l)react,304.0 kcal are consumed. 
E) When 123.88 g P4 (s)are produced,304.0 kcal are released.

Question 9

Which of the following states of matter should have the lowest entropy value?

Accepted Answer

A) a crystalline solid 
B) a liquid 
C) a gas 
D) Two of these have virtually the same entropy. 
E) all of the above

Question 10

All of the statements regarding the symbol ΔG are true except

Accepted Answer

A) it refers to the free energy of the reaction. 
B) it allows us to predict the spontaneity of a reaction. 
C) it allows us to identify an exothermic reaction. 
D) it allows us to identify an endergonic reaction. 
E) it describes the effect of both enthalpy and entropy on a reaction.

Question 11

S + O2 → SO2 + 70.8 kcal
Based on the reaction shown,which statement is true?

Accepted Answer

A) 70.8 kcal are produced when 1 g of sulfur reacts. 
B) 70.8 kcal are consumed when 1 g of sulfur reacts. 
C) 70.8 kcal are produced when 32.1 g of sulfur reacts. 
D) 70.8 kcal are consumed when 32.1 g of sulfur reacts. 
E) 70.8 kcal are produced when 1 g of sulfur dioxide is produced.

Question 12

In the process of dissolving sugar in water,the entropy increases.This means that the sign of ΔS is ________,and that the randomness of the system ________.

Accepted Answer

A) undetermined; increases 
B) positive; decreases 
C) positive; increases 
D) negative; decreases 
E) negative; increases

Question 13

Which factors would decrease the rate of a reaction?
I.Lowering the temperature
II.Increasing the concentration of reactants
III.Adding a catalyst

Accepted Answer

A) I only 
B) II only 
C) III only 
D) II and III 
E) I and III

Question 14

All of the statements are true for spontaneous reactions except

Accepted Answer

A) the value of ΔG is less than zero. 
B) the value of ΔG is unaffected by a catalyst. 
C) they are said to be exergonic. 
D) if the enthalpy change is unfavorable,they occur at a high temperature. 
E) the reaction rate is determined by the value of ΔG.

Question 15

Diatomic nitrogen is added to the equilibrium system:
N2 (g)+ H2 (g) 
2 NH3(g)+ heat
When a new equilibrium is established the concentration of H2 will be ________ the amount at the original equilibrium,and the amount of NH3 will be ________ the amount at the original equilibrium.

Accepted Answer

A) greater than; greater than 
B) greater than; less than 
C) less than; greater than 
D) less than; less than 
E) Both changes will be impossible to determine.

Question 16

The label on a package of cookies states that there are 100 calories per serving.Explain the different meanings of this statement to a chemist and to a nutritionist.Be sure your answer explains the difference between kilocalories and Calorie.

Accepted Answer

The answer of The label on a package of cookies...

Question 17

The position of the equilibrium for a system where K = 4.6 × 10-15 can be described as being favored to ________; the concentration of products is relatively ________.

Accepted Answer

A) the right; large 
B) the right; small 
C) the left; large 
D) the left; small 
E) neither direction; large

Question 18

Match the following.
-The amount of energy which must be invested in a reaction to get it started

Accepted Answer

A) exergonic 
B) endergonic 
C) exothermic 
D) endothermic 
E) activation energy
F)chemical equilibrium

Question 19

Calculate the enthalpy for the following reaction: N2 + O2 → 2 NO
Given the following bond dissociation energies: N2 = 226 kcal/mol,O2 = 199 kcal/mol and NO = 145 kcal/mol.

Accepted Answer

A) 135 kcal/mol 
B) -135 kcal/mol 
C) 280 kcal/mol 
D) -280 kcal/mol

Question 20

Entropy is used to

Accepted Answer

A) explain how energy is stored. 
B) explain how an exothermic reaction can become endothermic. 
C) indicate the disorder of a system. 
D) explain why most chemical reactions are exothermic. 
E) none of the above

Exam 7: Chemical Reactions: Energy, rates, and Equilibrium

Reaction rates are determined by all of the following factors except

Select the correct figure to match the description. -A fast reaction with a large negative free energy change

Which change to this reaction system would cause the equilibrium to shift to the right? N₂ (g) + 3 H₂ (g) 2 NH₃ (g) + heat

In the reaction A + B → AB,which of the following will not increase the rate?

All of the statements concerning free energy and spontaneity are true except

Consider the reaction shown: 2 CO (g) + O₂ (g) → CO₂ (g) + 135.2 kcal This reaction is because the sign of ΔH is .

Which factors would increase the rate of a chemical reaction? I.Increasing the temperature II.Removing products as they are formed III.Adding a catalyst

4 PCl₃(l) → P₄ (s) + 6 Cl₂ (g) ΔH = 304.0 kcal Based on the reaction shown,which statement is true?

Which of the following states of matter should have the lowest entropy value?

All of the statements regarding the symbol ΔG are true except

S + O₂ → SO₂ + 70.8 kcal Based on the reaction shown,which statement is true?

In the process of dissolving sugar in water,the entropy increases.This means that the sign of ΔS is ,and that the randomness of the system .

Which factors would decrease the rate of a reaction? I.Lowering the temperature II.Increasing the concentration of reactants III.Adding a catalyst

All of the statements are true for spontaneous reactions except

Diatomic nitrogen is added to the equilibrium system: N₂ (g) + H₂ (g) 2 NH₃(g) + heat When a new equilibrium is established the concentration of H₂ will be the amount at the original equilibrium,and the amount of NH₃ will be the amount at the original equilibrium.

The label on a package of cookies states that there are 100 calories per serving.Explain the different meanings of this statement to a chemist and to a nutritionist.Be sure your answer explains the difference between kilocalories and Calorie.

The position of the equilibrium for a system where K = 4.6 × 10^-15 can be described as being favored to ; the concentration of products is relatively .

Match the following. -The amount of energy which must be invested in a reaction to get it started

Calculate the enthalpy for the following reaction: N₂ + O₂ → 2 NO Given the following bond dissociation energies: N₂ = 226 kcal/mol,O2 = 199 kcal/mol and NO = 145 kcal/mol.

Entropy is used to

Exam 7: Chemical Reactions: Energy, rates, and Equilibrium

Reaction rates are determined by all of the following factors except

Select the correct figure to match the description. -A fast reaction with a large negative free energy change

Which change to this reaction system would cause the equilibrium to shift to the right? N2 (g) + 3 H2 (g) 2 NH3 (g) + heat

In the reaction A + B → AB,which of the following will not increase the rate?

All of the statements concerning free energy and spontaneity are true except

Consider the reaction shown: 2 CO (g) + O2 (g) → CO2 (g) + 135.2 kcal This reaction is ________ because the sign of ΔH is ________.

Which factors would increase the rate of a chemical reaction? I.Increasing the temperature II.Removing products as they are formed III.Adding a catalyst

4 PCl3 (l) → P4 (s) + 6 Cl2 (g) ΔH = 304.0 kcal Based on the reaction shown,which statement is true?

Which of the following states of matter should have the lowest entropy value?

All of the statements regarding the symbol ΔG are true except

S + O2 → SO2 + 70.8 kcal Based on the reaction shown,which statement is true?

In the process of dissolving sugar in water,the entropy increases.This means that the sign of ΔS is ________,and that the randomness of the system ________.

Which factors would decrease the rate of a reaction? I.Lowering the temperature II.Increasing the concentration of reactants III.Adding a catalyst

All of the statements are true for spontaneous reactions except

Diatomic nitrogen is added to the equilibrium system: N2 (g) + H2 (g) 2 NH3(g) + heat When a new equilibrium is established the concentration of H2 will be ________ the amount at the original equilibrium,and the amount of NH3 will be ________ the amount at the original equilibrium.

The label on a package of cookies states that there are 100 calories per serving.Explain the different meanings of this statement to a chemist and to a nutritionist.Be sure your answer explains the difference between kilocalories and Calorie.

The position of the equilibrium for a system where K = 4.6 × 10-15 can be described as being favored to ________; the concentration of products is relatively ________.

Match the following. -The amount of energy which must be invested in a reaction to get it started

Calculate the enthalpy for the following reaction: N2 + O2 → 2 NO Given the following bond dissociation energies: N2 = 226 kcal/mol,O2 = 199 kcal/mol and NO = 145 kcal/mol.

Entropy is used to

Which change to this reaction system would cause the equilibrium to shift to the right? N₂ (g) + 3 H₂ (g) 2 NH₃ (g) + heat

Consider the reaction shown: 2 CO (g) + O₂ (g) → CO₂ (g) + 135.2 kcal This reaction is because the sign of ΔH is .

4 PCl₃(l) → P₄ (s) + 6 Cl₂ (g) ΔH = 304.0 kcal Based on the reaction shown,which statement is true?

S + O₂ → SO₂ + 70.8 kcal Based on the reaction shown,which statement is true?

In the process of dissolving sugar in water,the entropy increases.This means that the sign of ΔS is ,and that the randomness of the system .

Diatomic nitrogen is added to the equilibrium system: N₂ (g) + H₂ (g) 2 NH₃(g) + heat When a new equilibrium is established the concentration of H₂ will be the amount at the original equilibrium,and the amount of NH₃ will be the amount at the original equilibrium.

The position of the equilibrium for a system where K = 4.6 × 10^-15 can be described as being favored to ; the concentration of products is relatively .

Calculate the enthalpy for the following reaction: N₂ + O₂ → 2 NO Given the following bond dissociation energies: N₂ = 226 kcal/mol,O2 = 199 kcal/mol and NO = 145 kcal/mol.