Question 1

Heat is absorbed in an _____ reaction.

Accepted Answer

endothermic

Question 2

A catalytic converter uses a catalyst to catalyze three reactions that clean up the exhaust from an auto engine. Which element is not used as a catalyst in catalytic converters?

Accepted Answer

A) platinum 
B) rhodium 
C) sulfur 
D) palladium 
A) platinum 
B) rhodium 
C) sulfur 
D) palladium C

Question 3

Which statement about catalysts is NOT true?

Accepted Answer

A) A catalyst increases the rate of a chemical reaction. 
B) A catalyst lowers the activation energy of a chemical reaction. 
C) A catalyst lowers the$\Delta$H of a chemical reaction. 
D) A catalyst is recovered unchanged in the reaction it catalyzes. 
A) A catalyst increases the rate of a chemical reaction. 
B) A catalyst lowers the activation energy of a chemical reaction. 
C) A catalyst lowers the$\Delta$H of a chemical reaction. 
D) A catalyst is recovered unchanged in the reaction it catalyzes. C

Question 4

A reversible reaction is said to have reached equilibrium when the concentrations of the reactants and products become equal.

Accepted Answer

A) True 
 B)False

Question 5

What is the gas phase chemical reaction that corresponds to the equilibrium constant expression shown below?

Accepted Answer

A) 2 A + 4 B   2 C 
B) A + B   C 
C) 2 C   2 A + 4 B 
D) 2 C   4 A + 2 B 
E) 4 A + 2 B   2 C 
A) 2 A + 4 B   2 C 
B) A + B   C 
C) 2 C   2 A + 4 B 
D) 2 C   4 A + 2 B 
E) 4 A + 2 B   2 C

Question 6

An equilibrium constant with a value of 1.5 × 10-9 indicates that at equilibrium

Accepted Answer

A) the reactants are favored. 
B) the products are favored. 
C) approximately equal concentrations of reactants and products are present. 
D) there are more products present than reactants. 
A) the reactants are favored. 
B) the products are favored. 
C) approximately equal concentrations of reactants and products are present. 
D) there are more products present than reactants.

Question 7

Consider the combustion reaction of propane: C3H8(g)+ 5 O2(g)$\rightarrow$3 CO2(g)+ 4 H2O(g), where $\Delta$H = -531 kcal. If 6.70 × 104 kcal of energy is released in the reaction, how many grams of oxygen were consumed?

Accepted Answer

A) 63.1 g of O2 
B) 2.02 × 104 g of O2 
C) 12.6 g of O2 
D) 404 g of O2 
A) 63.1 g of O2 
B) 2.02 × 104 g of O2 
C) 12.6 g of O2 
D) 404 g of O2

Question 8

The rusting of iron is described by the reaction: 4 Fe(s)+ 3 O2(g)$\rightarrow$ 2 Fe2O3(s). The formation of rust on an exposed piece of iron typically takes several months. Which of the following is NOT a reasonable assumption about this chemical reaction?

Accepted Answer

A) The formation of rust has a low reaction rate. 
B) The formation of rust has a low activation energy. 
C) The formation of rust would occur more slowly at higher altitudes where the concentration of oxygen is lower. 
D) The formation of rust would occur faster in the warmer summer months than in the cooler winter months. 
A) The formation of rust has a low reaction rate. 
B) The formation of rust has a low activation energy. 
C) The formation of rust would occur more slowly at higher altitudes where the concentration of oxygen is lower. 
D) The formation of rust would occur faster in the warmer summer months than in the cooler winter months.

Question 9

Consider the following reversible reaction at equilibrium: CO(g)+ Cl2(g)   COCl2(g). If chlorine gas is added to the reaction vessel, the equilibrium will shift to the right.

Accepted Answer

A) True 
 B)False

Question 10

Which bond is the weakest?

Accepted Answer

A) H-Br 
B) H-Cl 
C) H-F 
D) H-I 
A) H-Br 
B) H-Cl 
C) H-F 
D) H-I

Question 11

Consider the reaction, 3 NO2(g)+ H2O(l)$\rightarrow$  2 HNO3(aq)+ NO(g), where $\Delta$H = -137 kJ. How many kilojoules are released when 92.3 g of NO2 reacts?

Accepted Answer

A) 2.01 kJ are released 
B) 2.75 × 102 kJ are released 
C) 91.6 kJ are released 
D) 1.26 × 104 kJ are released 
A) 2.01 kJ are released 
B) 2.75 × 102 kJ are released 
C) 91.6 kJ are released 
D) 1.26 × 104 kJ are released

Question 12

Consider the reaction: 2 C2H6(g)+ 7 O2(g)$\rightarrow$ 4 CO2(g)+ 6 H2O(g). Decreasing the concentration of C2H6(g)will decrease the reaction rate.

Accepted Answer

A) True 
 B)False

Question 13

Which of the following is a true statement about the energy diagram shown below?

Accepted Answer

A) A labels the Ea of the reaction and B labels $\Delta$H of the reaction. 
B) A labels the $\Delta$H of the reaction and B labels Ea of the reaction. 
C) C labels the activation energy. 
D) D labels the reactants and E labels the products. 
A) A labels the Ea of the reaction and B labels $\Delta$H of the reaction. 
B) A labels the $\Delta$H of the reaction and B labels Ea of the reaction. 
C) C labels the activation energy. 
D) D labels the reactants and E labels the products.

Question 14

Energy is the capacity to do work.

Accepted Answer

A) True 
 B)False

Question 15

Consider the reaction: C3H8(g)+ 5 O2(g)$\rightarrow$3 CO2(g)+ 4 H2O(g), where $\Delta$H = -531 kcal/mol. How much heat is released when 3.40 × 1020 molecules of C3H8(g)is burned?

Accepted Answer

A) 3.33 kcal 
B) 0.300 kcal 
C) 6.40 × 1017 kcal 
D) 1.50 kcal 
A) 3.33 kcal 
B) 0.300 kcal 
C) 6.40 × 1017 kcal 
D) 1.50 kcal

Question 16

A peanut butter and jelly sandwich contains 9.00 g of fat, 6.00 g of protein, and 25.0 g of carbohydrate. How many Calories does this sandwich provide?

Accepted Answer

A) 205 Cal 
B) 360 Cal 
C) 160 Cal 
D) 260 Cal 
E) 190 Cal 
A) 205 Cal 
B) 360 Cal 
C) 160 Cal 
D) 260 Cal 
E) 190 Cal

Question 17

Which quantity represents the largest amount of stored energy?

Accepted Answer

A) 10 grams of fat 
B) 10 grams of carbohydrate 
C) 10 grams of protein 
D) 5 grams of carbohydrate plus 5 grams of protein 
E) 5 grams of protein plus 5 grams of fat 
A) 10 grams of fat 
B) 10 grams of carbohydrate 
C) 10 grams of protein 
D) 5 grams of carbohydrate plus 5 grams of protein 
E) 5 grams of protein plus 5 grams of fat

Question 18

The energy of the reacting molecules affects whether a particular collision will lead to a chemical reaction.

Accepted Answer

A) True 
 B)False

Question 19

Which of the following is always necessary for a chemical reaction to occur between two reactants, A and B?

Accepted Answer

A) Equal amounts of A and B must be present 
B) A and B must be present in the same physical state 
C) The reaction must be carried out at a temperature higher than room temperature 
D) A and B must collide with the proper orientation and with a certain minimum amount of energy 
A) Equal amounts of A and B must be present 
B) A and B must be present in the same physical state 
C) The reaction must be carried out at a temperature higher than room temperature 
D) A and B must collide with the proper orientation and with a certain minimum amount of energy

Question 20

Which of the following will increase the rate of a reaction?

Accepted Answer

A) increasing the temperature 
B) increasing the concentration of a reactant 
C) adding a catalyst 
D) ensuring that the reactants are properly aligned when they collide 
E) All of the above changes will increase the rate of a reaction. 
A) increasing the temperature 
B) increasing the concentration of a reactant 
C) adding a catalyst 
D) ensuring that the reactants are properly aligned when they collide 
E) All of the above changes will increase the rate of a reaction.

Exam 6: Energy Changes, Reaction Rates, and Equilibrium

Heat is absorbed in an _____ reaction.

A catalytic converter uses a catalyst to catalyze three reactions that clean up the exhaust from an auto engine. Which element is not used as a catalyst in catalytic converters?

Which statement about catalysts is NOT true?

A reversible reaction is said to have reached equilibrium when the concentrations of the reactants and products become equal.

What is the gas phase chemical reaction that corresponds to the equilibrium constant expression shown below?

An equilibrium constant with a value of 1.5 × 10-9 indicates that at equilibrium

Consider the combustion reaction of propane: C3H8(g)+ 5 O2(g) →\rightarrow→ 3 CO2(g)+ 4 H2O(g), where Δ\DeltaΔ H = -531 kcal. If 6.70 × 104 kcal of energy is released in the reaction, how many grams of oxygen were consumed?

The rusting of iron is described by the reaction: 4 Fe(s)+ 3 O2(g) →\rightarrow→ 2 Fe2O3(s). The formation of rust on an exposed piece of iron typically takes several months. Which of the following is NOT a reasonable assumption about this chemical reaction?

Consider the following reversible reaction at equilibrium: CO(g)+ Cl2(g) COCl2(g). If chlorine gas is added to the reaction vessel, the equilibrium will shift to the right.

Which bond is the weakest?

Consider the reaction, 3 NO2(g)+ H2O(l) →\rightarrow→ 2 HNO3(aq)+ NO(g), where Δ\DeltaΔ H = -137 kJ. How many kilojoules are released when 92.3 g of NO2 reacts?

Consider the reaction: 2 C2H6(g)+ 7 O2(g) →\rightarrow→ 4 CO2(g)+ 6 H2O(g). Decreasing the concentration of C2H6(g)will decrease the reaction rate.

Which of the following is a true statement about the energy diagram shown below?

Energy is the capacity to do work.

Consider the reaction: C3H8(g)+ 5 O2(g) →\rightarrow→ 3 CO2(g)+ 4 H2O(g), where Δ\DeltaΔ H = -531 kcal/mol. How much heat is released when 3.40 × 1020 molecules of C3H8(g)is burned?

A peanut butter and jelly sandwich contains 9.00 g of fat, 6.00 g of protein, and 25.0 g of carbohydrate. How many Calories does this sandwich provide?

Which quantity represents the largest amount of stored energy?

The energy of the reacting molecules affects whether a particular collision will lead to a chemical reaction.

Which of the following is always necessary for a chemical reaction to occur between two reactants, A and B?

Which of the following will increase the rate of a reaction?

Matter and Measurement

Atoms and the Periodic Table

Ionic Compounds

Covalent Compounds

Chemical Reactions

Gases, Liquids, and Solids

Solutions

Acids and Bases

Nuclear Chemistry

Introduction to Organic Molecules and Functional Groups

Alkanes

Unsaturated Hydrocarbons

Organic Compounds That Contain Oxygen, Halogen, or Sulfur

The Three-Dimensional Shape of Molecules

Aldehydes and Ketones

Carboxylic Acids, Esters, and Amides

Amines and Neurotransmitters

Lipids

Carbohydrates

Amino Acids, Proteins, and Enzymes

Nucleic Acids and Protein Synthesis

Digestion and the Conversion of Food Into Energy

Carbohydrate, Lipid, and Protein Metabolism

Filters

An equilibrium constant with a value of 1.5 × 10^-9 indicates that at equilibrium

Consider the combustion reaction of propane: C₃H₈(g)+ 5 O₂(g) $\rightarrow$ 3 CO₂(g)+ 4 H₂O(g), where $\Delta$ H = -531 kcal. If 6.70 × 10⁴ kcal of energy is released in the reaction, how many grams of oxygen were consumed?

The rusting of iron is described by the reaction: 4 Fe(s)+ 3 O₂(g) $\rightarrow$ 2 Fe₂O₃(s). The formation of rust on an exposed piece of iron typically takes several months. Which of the following is NOT a reasonable assumption about this chemical reaction?

Consider the following reversible reaction at equilibrium: CO(g)+ Cl₂(g) COCl₂(g). If chlorine gas is added to the reaction vessel, the equilibrium will shift to the right.

Consider the reaction, 3 NO₂(g)+ H₂O(l) $\rightarrow$ 2 HNO₃(aq)+ NO(g), where $\Delta$ H = -137 kJ. How many kilojoules are released when 92.3 g of NO₂reacts?

Consider the reaction: 2 C₂H₆(g)+ 7 O₂(g) $\rightarrow$ 4 CO₂(g)+ 6 H₂O(g). Decreasing the concentration of C₂H₆(g)will decrease the reaction rate.

Consider the reaction: C₃H₈(g)+ 5 O₂(g) $\rightarrow$ 3 CO₂(g)+ 4 H₂O(g), where $\Delta$ H = -531 kcal/mol. How much heat is released when 3.40 × 10²⁰ molecules of C₃H₈(g)is burned?