Question 1

Which of the following is not true when the temperature of the reaction mixture is decreased?

Accepted Answer

When the temperature of the reaction mixture is decreased, the average kinetic energy of both the reactant and product molecules is decreased, the rate of the reaction is decreased, and the fraction of reactant molecules that have low kinetic energies is increased. However, the activation energy of the reaction is not increased, but rather it becomes more difficult for the reactant molecules to overcome the existing activation energy barrier and to reach the transition state required for the reaction to proceed. Therefore, choice D is not true.

Question 2

Which statement is true about the reaction energy profile?

Accepted Answer

The reaction energy profile plots the relative energies of both the reactants and products, and energy is plotted on the y-axis. The progress of the reaction is traced on the x-axis. Therefore, all of the statements in the options are true.

Question 3

Which of the following is true about enzymes?

Accepted Answer

All of the statements are true. Enzymes speed up reactions in a highly selective manner by binding specifically to certain reactant molecules in their active site, which is a specifically shaped pocket in the enzyme molecule. Enzymes are usually proteins but can also be RNA molecules called ribozymes.

Question 4

Consider the reaction X → Y with the following data: Energy of reactants = 50 kJ/mole;
Energy of reaction = -30 kJ/mole;
Energy of transition state = 90 kJ/mole.
The energy of products for the reaction is ________ kJ/mole.

Accepted Answer

The energy of the products can be calculated by adding the energy of reaction to the energy of reactants: 50 kJ/mole + (-30 kJ/mole) = 20 kJ/mole.

Question 5

Which of the following is not a substitution reaction?

Accepted Answer

A substitution reaction is a chemical reaction in which an atom or group of atoms is replaced by another atom or group of atoms. Option C is an oxidation reaction where oxygen is added to iron to form iron oxide. This does not involve the replacement of one group with another, so it is not a substitution reaction.

Question 6

In order for a chemical reaction to occur, ________.

Accepted Answer

In order for a chemical reaction to occur, the reactants must possess sufficient energy to overcome the barrier of the activation energy. This energy is required to break the existing bonds in the reactants and allow new bonds to form in the products. Without this energy, the reaction will not occur. Therefore, option D is the correct answer.

Question 7

Which of the following is an example of a substitution reaction?

Accepted Answer

In option A, the reaction involves a substitution of OH with Br and is known as a nucleophilic substitution reaction. Option B is a decomposition reaction, Option C is a combination reaction, and Option D is a double displacement reaction.

Question 8

Which of the following does not influence the speed of a chemical reaction?

Accepted Answer

The molecular mass of the reactants does not directly influence the speed of a chemical reaction. The factors that do influence the speed of a chemical reaction are concentration of the reactants, surface area of solid reactants, and temperature.

Question 9

Which of the following is endothermic?

Accepted Answer

Melting ice is endothermic because it requires energy to break the hydrogen bonds between water molecules in the solid ice and turn it into liquid water. This energy is absorbed from the surroundings, making the process endothermic.

Question 10

If the products have a higher energy than the reactants ________.

Accepted Answer

When products have a higher energy than the reactants, the reaction absorbs energy from its surroundings, making it endothermic, and it is also true that the reactants have less energy than the products.

Question 11

Consider the reaction C → D with the following data: Energy of reactants = 30 kJ/mole;
Energy of products = 20 kJ/mole;
Energy of transition state = 60 kJ/mole.
The reaction is ________, has a heat of reaction of ________kJ/mole, and the energy of activation is ________ kJ/mole.

Accepted Answer

The reaction is exothermic because the energy of the products (20 kJ/mole) is less than the energy of the reactants (30 kJ/mole). The heat of reaction is calculated by subtracting the energy of the products from the energy of the reactants: 30 kJ/mole - 20 kJ/mole = -10 kJ/mole. The energy of activation is given as 60 kJ/mole.

Question 12

Which of the following "adjustments" can be made to a chemical reaction system to increase the rate of reaction?

Accepted Answer

All three options, increasing the reaction temperature, increasing the concentrations of the reactants, and adding a catalyst, can increase the rate of reaction. Increasing the temperature provides more energy for the molecules to collide and react. Increasing the reactant concentrations increases the likelihood of successful collisions between reactant molecules. Adding a catalyst lowers the activation energy required for the reaction to occur, which speeds up the reaction.

Question 13

Consider the reaction X → Y with the following data: Energy of reactants = 25 kJ/mole;
Energy of products = 75 kJ/mole;
Energy of transition state = 100 kJ/mole.
The energy of activation for the reverse reaction is ________ kJ/mole.

Accepted Answer

The answer of Consider the reaction X → Y with...

Question 14

If the reaction has a negative overall energy change, then ________.

Accepted Answer

A negative overall energy change indicates that energy is being released by the reaction, which means the reaction is exothermic.

Question 15

Consider the reaction A → B with the following data: Energy of reactants = 50 kJ/mole;
Energy of products = 70 kJ/mole;
Energy of transition state = 80 kJ/mole.
The reaction is ________, has a heat of reaction of ________ kJ/mole, and the energy of activation is ________ kJ/mole.

Accepted Answer

The reaction is endothermic because the energy of the products is higher than the energy of the reactants. The heat of reaction is 20 kJ/mole (70 - 50), and the energy of activation is 30 kJ/mole (80 - 50).

Question 16

Which of the following represents a reaction coordinate diagram for a chemical reaction whose ΔErxn = 0?

Accepted Answer

The answer of Which of the following represents a reaction...

Question 17

Which of the following reaction coordinate diagrams represents a chemical reaction that is exothermic?

Accepted Answer

The answer of Which of the following reaction coordinate diagrams...

Question 18

The difference in energy between the reactants and products in a chemical reaction is called ________.

Accepted Answer

The difference in energy between the reactants and products in a chemical reaction is called the heat of reaction. The activation energy is the energy required to get a reaction started and the energy of products refers to the total energy contained within the products after the reaction has occurred.

Question 19

Which of the following reaction coordinate diagrams represents a chemical reaction that is endothermic?

Accepted Answer

The answer of Which of the following reaction coordinate diagrams...

Question 20

Which of the following is an exothermic reaction?

Accepted Answer

All the given reactions involve the release of heat, which means they are exothermic reactions. Burning propane gas and gasoline releases heat, whereas detonating nitroglycerine creates an explosive force that releases heat as well. Therefore, all the given options are exothermic reactions.

Quiz 13: When Reactants Turn Into Products

Which of the following is not true when the temperature of the reaction mixture is decreased?

Which statement is true about the reaction energy profile?

Which of the following is true about enzymes?

Consider the reaction X → Y with the following data: Energy of reactants = 50 kJ/mole; Energy of reaction = -30 kJ/mole; Energy of transition state = 90 kJ/mole. The energy of products for the reaction is ________ kJ/mole.

Which of the following is not a substitution reaction?

In order for a chemical reaction to occur, ________.

Which of the following is an example of a substitution reaction?

Which of the following does not influence the speed of a chemical reaction?

Which of the following is endothermic?

If the products have a higher energy than the reactants ________.

Consider the reaction C → D with the following data: Energy of reactants = 30 kJ/mole; Energy of products = 20 kJ/mole; Energy of transition state = 60 kJ/mole. The reaction is , has a heat of reaction of kJ/mole, and the energy of activation is kJ/mole.

Which of the following "adjustments" can be made to a chemical reaction system to increase the rate of reaction?

Consider the reaction X → Y with the following data: Energy of reactants = 25 kJ/mole; Energy of products = 75 kJ/mole; Energy of transition state = 100 kJ/mole. The energy of activation for the reverse reaction is ________ kJ/mole.

If the reaction has a negative overall energy change, then ________.

Consider the reaction A → B with the following data: Energy of reactants = 50 kJ/mole; Energy of products = 70 kJ/mole; Energy of transition state = 80 kJ/mole. The reaction is , has a heat of reaction of kJ/mole, and the energy of activation is kJ/mole.

Which of the following represents a reaction coordinate diagram for a chemical reaction whose ΔErxn = 0?

Which of the following reaction coordinate diagrams represents a chemical reaction that is exothermic?

The difference in energy between the reactants and products in a chemical reaction is called ________.

Which of the following reaction coordinate diagrams represents a chemical reaction that is endothermic?

Which of the following is an exothermic reaction?

Quiz 13: When Reactants Turn Into Products

Which of the following is not true when the temperature of the reaction mixture is decreased?

Which statement is true about the reaction energy profile?

Which of the following is true about enzymes?

Consider the reaction X → Y with the following data: Energy of reactants = 50 kJ/mole; Energy of reaction = -30 kJ/mole; Energy of transition state = 90 kJ/mole. The energy of products for the reaction is ________ kJ/mole.

Which of the following is not a substitution reaction?

In order for a chemical reaction to occur, ________.

Which of the following is an example of a substitution reaction?

Which of the following does not influence the speed of a chemical reaction?

Which of the following is endothermic?

If the products have a higher energy than the reactants ________.

Consider the reaction C → D with the following data: Energy of reactants = 30 kJ/mole; Energy of products = 20 kJ/mole; Energy of transition state = 60 kJ/mole. The reaction is ________, has a heat of reaction of ________kJ/mole, and the energy of activation is ________ kJ/mole.

Which of the following "adjustments" can be made to a chemical reaction system to increase the rate of reaction?

Consider the reaction X → Y with the following data: Energy of reactants = 25 kJ/mole; Energy of products = 75 kJ/mole; Energy of transition state = 100 kJ/mole. The energy of activation for the reverse reaction is ________ kJ/mole.

If the reaction has a negative overall energy change, then ________.

Consider the reaction A → B with the following data: Energy of reactants = 50 kJ/mole; Energy of products = 70 kJ/mole; Energy of transition state = 80 kJ/mole. The reaction is ________, has a heat of reaction of ________ kJ/mole, and the energy of activation is ________ kJ/mole.

Which of the following represents a reaction coordinate diagram for a chemical reaction whose ΔErxn = 0?

Which of the following reaction coordinate diagrams represents a chemical reaction that is exothermic?

The difference in energy between the reactants and products in a chemical reaction is called ________.

Which of the following reaction coordinate diagrams represents a chemical reaction that is endothermic?

Which of the following is an exothermic reaction?

Consider the reaction C → D with the following data: Energy of reactants = 30 kJ/mole; Energy of products = 20 kJ/mole; Energy of transition state = 60 kJ/mole. The reaction is , has a heat of reaction of kJ/mole, and the energy of activation is kJ/mole.

Consider the reaction A → B with the following data: Energy of reactants = 50 kJ/mole; Energy of products = 70 kJ/mole; Energy of transition state = 80 kJ/mole. The reaction is , has a heat of reaction of kJ/mole, and the energy of activation is kJ/mole.