energy transfer in reactions 9/3/25

Question 1

What is the definition of bond energy?

Answer 1

The amount of energy required to break one mole of a bond in a molecule.

Question 2

True or False: Energy is released when bonds are formed.

Answer 2

True

Question 3

What is the formula for calculating the overall energy change in a reaction?

Answer 3

Overall energy change = Total bond energies of reactants - Total bond energies of products

Question 4

Fill in the blank: The process of breaking bonds requires _____ energy.

Answer 4

input

Question 5

What type of reaction absorbs energy from the surroundings?

Answer 5

Endothermic reaction

Question 6

What type of reaction releases energy to the surroundings?

Answer 6

Exothermic reaction

Question 7

What is the unit of bond energy?

Answer 7

Kilojoules per mole (kJ/mol)

Question 8

True or False: The bond energy of a double bond is generally higher than that of a single bond.

Answer 8

True

Question 9

What does the term ‘reaction rate’ refer to?

Answer 9

The speed at which reactants are converted into products in a chemical reaction.

Question 10

Which factor does NOT affect the rate of a chemical reaction?

Answer 10

The color of the reactants

Question 11

Fill in the blank: Increasing the temperature generally _____ the reaction rate.

Answer 11

increases

Question 12

What is the effect of increasing concentration on reaction rate?

Answer 12

It typically increases the reaction rate.

Question 13

What role do catalysts play in chemical reactions?

Answer 13

They speed up the reaction rate without being consumed.

Question 14

True or False: A higher surface area of reactants increases the reaction rate.

Answer 14

True

Question 15

What is a common method for measuring the rate of a reaction?

Answer 15

Measuring the change in concentration of reactants or products over time.

Question 16

Fill in the blank: The rate of reaction can be expressed as the change in _____ over time.

Answer 16

concentration

Question 17

What does a steeper slope on a concentration vs. time graph indicate?

Answer 17

A faster reaction rate.

Question 18

What is activation energy?

Answer 18

The minimum energy required for a reaction to occur.

Question 19

True or False: All reactions require activation energy to start.

Answer 19

True

Question 20

What does the term ‘endothermic’ imply about a reaction?

Answer 20

It absorbs heat energy from the surroundings.

Question 21

What is the effect of pressure on the reaction rate of gases?

Answer 21

Increasing pressure generally increases the reaction rate.

Question 22

What is the difference between a homogeneous and heterogeneous catalyst?

Answer 22

Homogeneous catalysts are in the same phase as the reactants; heterogeneous catalysts are in a different phase.

Question 23

Fill in the blank: The energy profile of an exothermic reaction shows energy _____ during the reaction.

Answer 23

release

Question 24

What is the role of temperature in the collision theory?

Answer 24

Higher temperatures increase the energy and frequency of collisions between particles.

Question 25

True or False: A catalyst lowers the activation energy of a reaction.

Answer 25

True

Question 26

What happens to the reaction rate when temperature is decreased?

Answer 26

The reaction rate generally decreases.

Question 27

What is the significance of the transition state in a chemical reaction?

Answer 27

It is a temporary state during the process of breaking and forming bonds.

Question 28

Fill in the blank: The rate of reaction is typically _____ at the beginning and decreases over time.

Answer 28

fastest

Question 29

What is the effect of a higher concentration of reactants on the frequency of collisions?

Answer 29

It increases the frequency of collisions.

Question 30

True or False: The energy needed to break bonds is always equal to the energy released when new bonds are formed.

Answer 30

False

Question 31

What does a catalyst do to the energy profile of a reaction?

Answer 31

It lowers the activation energy barrier.

Question 32

What can be measured to determine the rate of a reaction involving gas production?

Answer 32

The volume of gas produced over time.

Question 33

Fill in the blank: In an exothermic reaction, the products have _____ energy than the reactants.

Answer 33

lower

Question 34

What is the effect of adding an inert gas to a reaction mixture at constant volume?

Answer 34

It does not affect the reaction rate.

Question 35

True or False: The bond energies of different types of bonds can vary significantly.

Answer 35

True

Question 36

What is the primary factor that affects the rate of a reaction involving solids?

Answer 36

Surface area of the solid reactants.

Question 37

Fill in the blank: A reaction is said to be _____ if it releases energy to the surroundings.

Answer 37

exothermic

Question 38

What does the term 'rate constant' refer to in chemical kinetics?

Answer 38

A proportionality constant that relates the rate of a reaction to the concentration of reactants.