Rates of Reaction Quizzes: Test Your Understanding

Question 1

Which experimental procedure can be used to determine the order of a reaction with respect to a specific reactant?

Accepted Answer

Using different concentrations of the reactant of interest while keeping the concentrations of other reactants constant and measuring the rate of reaction.

Answer

Varying the temperature of the reaction and measuring the rate of reaction.

Question 2

How does the physical state of reactants (solid, liquid, or gas) primarily affect the rate of a chemical reaction?

Accepted Answer

Surface area available for collisions between particles

Answer

Activation energy required for the reaction

Answer

Concentration of reactants in the reaction

Answer

Temperature of the reaction

Question 3

Question:

Explain how adding a catalyst affects the activation energy of a reaction and discuss the implications of this for the rate of the reaction.

Accepted Answer

A catalyst lowers the activation energy, making reactions faster.

Answer

A catalyst increases the activation energy, making reactions slower.

Answer

A catalyst has no effect on the activation energy.

Answer

A catalyst increases the number of reacting particles.

Question 4

How can controlling activation energy be used to optimize reaction rates in practical applications?

Accepted Answer

Lowering activation energy allows reactions to occur faster at lower temperatures, saving energy in industrial processes.

Answer

Increasing activation energy can make reactions happen instantly, boosting manufacturing efficiency.

Answer

Changing activation energy doesn't affect reaction rates, making it unimportant in practical applications.

Answer

Activation energy only affects reactions in labs, limiting its practical uses.

Question 5

In chemical reactions, inhibitors play a crucial role. Describe how inhibitors work, their impact on reaction rates, and the factors that influence their effectiveness.

Accepted Answer

Inhibitors bind to enzymes, blocking their active sites and hindering substrate binding.

Answer

Inhibitors accelerate reactions by lowering the activation energy.

Answer

Inhibitors elevate the temperature of reactions, leading to an increase in reaction rate.

Answer

Inhibitors have no effect on reaction rates.

Question 6

In an experiment to test how surface area affects the rate of a heterogeneous catalytic reaction, which variable should you change to test your hypothesis?

Accepted Answer

Surface area of catalyst

Answer

Type of catalyst

Answer

Mass of reactant

Answer

Temperature

Question 7

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

Accepted Answer

Volume of the reaction mixture

Answer

Surface area of reactants

Answer

Concentration of reactants

Answer

Temperature of the reaction

Question 8

How will increasing the temperature of a reaction affect its rate?

Accepted Answer

Increase the rate

Answer

Decrease the rate

Answer

Have no effect on the rate

Answer

Reverse the reaction

Question 9

Which factor will NOT increase the rate of a heterogeneous reaction?

Accepted Answer

Increasing the concentration of the gaseous reactant

Answer

Increasing the surface area of the solid reactant

Answer

Increasing the temperature

Answer

Stirring the reaction mixture

Question 10

Which factor will generally increase the rate of a chemical reaction?

Accepted Answer

Increasing the surface area of the reactants

Answer

Decreasing the temperature

Answer

Decreasing the concentration of the reactants

Answer

Removing a catalyst

Question 11

Which of the following is the catalyst used in the Haber process?

Accepted Answer

Platinum

Answer

Iron

Answer

Carbon

Answer

Copper

Question 12

What conclusion can be drawn from the observation that the reaction rate of the reaction between magnesium and hydrochloric acid increases as the surface area of the magnesium increases?

Accepted Answer

The reaction is heterogeneous

Answer

The reaction is homogeneous

Answer

The reaction is spontaneous

Answer

The reaction is not affected by surface area

Question 13

Define activation energy

Accepted Answer

The minimum amount of energy that must be supplied to the reactants in order for a reaction to occur

Answer

The maximum amount of energy that can be released in a reaction

Answer

The average amount of energy that is released in a reaction

Answer

The energy difference between the reactants and the products

Question 14

Which factor will decrease the activation energy of a reaction?

Accepted Answer

Adding a catalyst

Answer

Increasing the temperature

Answer

Decreasing the concentration of the reactants

Answer

Increasing the surface area of the reactants

Question 15

What conclusion can be drawn from the observation that the reaction rate of the reaction between hydrogen and oxygen increases as the pressure of the gases increases?

Accepted Answer

The reaction is a gas phase reaction

Answer

The reaction is a liquid phase reaction

Answer

The reaction is a solid phase reaction

Answer

The reaction is not affected by pressure

Question 16

If the concentration of reactant A in the reaction A + B → C is doubled, what will happen to the reaction rate?

Accepted Answer

Double

Answer

Remain unchanged

Answer

Halve

Answer

Quadruple

Question 17

Which change would increase the surface area of a solid reactant?

Accepted Answer

Crushing it into a powder

Answer

Dissolving it in water

Answer

Heating it to a higher temperature

Answer

Stirring it rapidly

Question 18

Which metal is commonly used as a catalyst in industrial processes?

Accepted Answer

Platinum

Answer

Gold

Answer

Copper

Answer

Silver

Question 19

Which of the following reactions is an example of a heterogeneous reaction?

Accepted Answer

Reaction between carbon monoxide and oxygen

Answer

Reaction between hydrogen and oxygen

Answer

Reaction between sodium and chlorine

Answer

Reaction between hydrochloric acid and sodium hydroxide

Question 20

A catalyst increases the rate of a reaction by:

Accepted Answer

Decreasing the activation energy of the reaction

Answer

Providing an alternative pathway for the reaction

Answer

Increasing the temperature of the reaction

Answer

Removing the products from the reaction mixture

Question 21

Which of the following actions would enhance the surface area of a solid reactant?

Accepted Answer

Grinding the solid into a powder

Answer

Dissolving the solid in a solvent

Answer

Heating the solid to its melting point

Answer

Compressing the solid into a pellet

Question 22

Define the activation energy of a reaction.

Accepted Answer

The minimum energy required for reactants to react.

Answer

The maximum energy released by the reaction.

Answer

The energy difference between reactants and products.

Answer

The speed at which the reaction occurs.

Question 23

What is a catalyst?

Accepted Answer

A substance that accelerates a reaction without being consumed.

Answer

A substance that slows down a reaction without being consumed.

Answer

A substance that is consumed in a reaction and releases heat.

Answer

A substance that is consumed in a reaction and emits light.

Question 24

Explain how a catalyst operates.

Accepted Answer

It lowers the activation energy of the reaction.

Answer

It raises the concentration of the reactants.

Answer

It elevates the temperature of the reaction.

Answer

It removes the products of the reaction.

Question 25

Which of the following is an example of an enzyme-catalyzed reaction?

Accepted Answer

Food digestion

Answer

Fuel combustion

Answer

Dynamite explosion

Answer

Iron rusting

Question 26

Which method can be used to investigate the impact of temperature on reaction rates?

Accepted Answer

Varying the reaction temperature and measuring the rate.

Answer

Varying the reactant concentration and measuring the rate.

Answer

Varying the reactant surface area and measuring the rate.

Answer

Adding a catalyst to the reaction and measuring the rate.

Question 27

Which of the following changes would increase the rate of a reaction between an acid and a base?

Accepted Answer

Adding a catalyst

Answer

Lowering the concentration of the base

Answer

Decreasing the surface area of the reactants

Answer

Lowering the temperature

Question 28

Which of the following factors does NOT influence the rate of a chemical reaction?

Accepted Answer

Gravity

Answer

Temperature

Answer

Concentration

Answer

Surface area

Question 29

As the temperature of a reaction increases, the rate of the reaction:

Accepted Answer

Increases

Answer

Decreases

Answer

Remains constant

Answer

Becomes unpredictable

Question 30

A reaction has a rate constant of 0.05 mol/L/s at 25°C. If the concentration of the reactants is 1.5 mol/L, what is the reaction rate?

Accepted Answer

0.075 mol/L/s

Answer

0.0075 mol/L/s

Answer

0.05 mol/L/s

Answer

0.15 mol/L/s

Question 31

A reaction has an activation energy of 100 kJ/mol. What is the minimum energy required for the colliding particles to initiate the reaction?

Accepted Answer

100 kJ/mol

Answer

50 kJ/mol

Answer

150 kJ/mol

Answer

200 kJ/mol

Question 32

Which of the following factors does not affect the rate of a chemical reaction?

Accepted Answer

The shape of the reactants

Answer

Temperature

Answer

Concentration of the reactants

Answer

Surface area of the reactants

Question 33

How does increasing the temperature of a reaction affect the kinetic energy of the reactants?

Accepted Answer

Increases kinetic energy

Answer

Decreases kinetic energy

Answer

Has no effect on kinetic energy

Answer

Cannot be determined

Question 34

In a reaction, a solid reactant is slowly dissolved in a liquid reactant. How does increasing the surface area of the solid reactant affect the initial rate of the reaction?

Accepted Answer

Increases the initial rate

Answer

Decreases the initial rate

Answer

Has no effect on the initial rate

Answer

Cannot be determined

Question 35

Which of the following reactions is most likely to be a homogeneous reaction?

Accepted Answer

Neutralization of an acid with a base

Answer

Burning of wood

Answer

Precipitation of a salt from solution

Answer

Rusting of iron

Question 36

Which of these factors does NOT directly influence the speed of a chemical reaction?

Accepted Answer

Volume of the reaction container

Answer

Temperature

Answer

Concentration of reactants

Answer

Surface area of reactants

Question 37

How does a catalyst affect a reaction?

Accepted Answer

Lowers the activation energy

Answer

Increases the temperature

Answer

Alters the reaction products

Answer

Consumes one of the reactants

Question 38

Which reaction is an example of a heterogeneous reaction?

Accepted Answer

Iron reacts with copper to form an alloy

Answer

Hydrogen reacts with oxygen to form water

Answer

Sodium reacts with chlorine to form sodium chloride

Answer

Carbon monoxide reacts with oxygen to form carbon dioxide

Question 39

In a reaction between two gases, the reaction rate is related to:

Accepted Answer

The product of the partial pressures of the gases

Answer

The sum of the partial pressures of the gases

Answer

The difference in the partial pressures of the gases

Answer

The square of the partial pressure of one of the gases

Question 40

How do catalysts affect the activation energy of a reaction?

Accepted Answer

Catalysts lower the activation energy, speeding up reactions.

Answer

Catalysts increase the activation energy, slowing down reactions.

Answer

Catalysts have no impact on the activation energy of a reaction.

Answer

Catalysts increase the activation energy but also increase the reaction rate.

Question 41

Increasing the temperature of a reaction will typically:

Accepted Answer

Increase the number of effective collisions

Answer

Decrease the activation energy

Answer

Decrease the rate of reaction

Answer

Have no effect on the reaction rate

Question 42

A reaction with a higher rate constant will:

Accepted Answer

React more quickly

Answer

React more slowly

Answer

Have a lower activation energy

Answer

Produce fewer products

Question 43

Which of the following is NOT a factor that typically affects the rate of a chemical reaction?

Accepted Answer

Mass of the reactants

Answer

Temperature

Answer

Concentration

Answer

Surface area

Question 44

To increase the surface area of a powdered reactant, which of these methods would be effective?

Accepted Answer

Crush the powder into finer particles

Answer

Heat the powder

Answer

Dissolve the powder in water

Answer

Add a catalyst to the powder

Question 45

A student hypothesizes that raising the concentration of sodium thiosulfate in a reaction between sodium thiosulfate and hydrochloric acid will lead to:

Accepted Answer

An increase in reaction rate

Answer

A decrease in reaction rate

Answer

No change in reaction rate

Answer

A reversal of the reaction direction

Question 46

Which of the following reactions is considered homogeneous?

Accepted Answer

Dissolving sugar in water

Answer

Burning wood

Answer

Rusting of iron

Answer

Photosynthesis

Question 47

The activation energy of a reaction refers to:

Accepted Answer

The minimum energy required for a reaction to occur

Answer

The maximum energy released by a reaction

Answer

The average energy of reactants

Answer

The energy difference between reactants and products

Question 48

Which of the following is NOT a factor that influences the rate of a chemical reaction?

Accepted Answer

Reactor volume

Answer

Temperature

Answer

Concentration

Answer

Surface area

Question 49

The proper unit for expressing the rate of a chemical reaction is:

Accepted Answer

mol/(dm³ s)

Answer

M/s

Answer

M/min

Answer

dm³/(mol s)

Question 50

A researcher measures the time taken for a certain amount of reactant to be consumed at various temperatures. Which type of graph would best represent their findings?

Accepted Answer

A curve where the slope increases as temperature rises

Answer

A straight line with a positive slope

Answer

A straight line with a negative slope

Answer

A curve where the slope decreases as temperature rises

Question 51

A researcher investigates the effect of a catalyst on the activation energy of a reaction. Which type of graph would best represent their findings?

Accepted Answer

A graph where the activation energy is lower for the catalyzed reaction

Answer

A graph where the activation energy is higher for the catalyzed reaction

Answer

A graph where the activation energy is the same for both reactions

Answer

A graph where the catalyzed reaction has no activation energy

Question 52

Increasing the temperature of a reaction usually results in:

Accepted Answer

Increased frequency of collisions

Answer

Decreased activation energy

Answer

Decreased number of successful collisions

Answer

No change in reaction rate

Question 53

A catalyst is a substance that:

Accepted Answer

Decreases the activation energy of a reaction

Answer

Increases the activation energy of a reaction

Answer

Changes the products of a reaction

Answer

Consumes one of the reactants

Question 54

The rate law for a reaction is an equation that expresses the relationship between the:

Accepted Answer

Rate of the reaction and the concentrations of the reactants

Answer

Equilibrium constant and the concentrations of the products

Answer

Activation energy and the temperature

Answer

Surface area and the particle size

Question 55

Which of the following graphs shows the relationship between the concentration of a reactant and the rate of a reaction?

Accepted Answer

A straight line with a positive gradient

Answer

A straight line with a negative gradient

Answer

A curve that increases rapidly at first and then levels off

Answer

A curve that decreases rapidly at first and then levels off

Question 56

A catalyst is a substance that:

Accepted Answer

Increases the rate of a reaction **without being consumed**

Answer

Decreases the rate of a reaction without being consumed

Answer

Is consumed in the reaction and increases the rate

Answer

Is consumed in the reaction and decreases the rate

Question 57

The half-life of a reaction refers to the time it takes for:

Accepted Answer

The concentration of the reactants to decrease by half

Answer

The concentration of the products to increase by half

Answer

The rate of the reaction to decrease by half

Answer

The temperature of the reaction to increase by half

Question 58

Which of the following reactions involves only one reactant molecule?

Accepted Answer

Decomposition of hydrogen peroxide to form water and oxygen

Answer

Reaction between hydrogen and chlorine to form hydrogen chloride

Answer

Reaction between sodium and chlorine to form sodium chloride

Answer

Reaction between carbon monoxide and oxygen to form carbon dioxide

Question 59

If a reaction has an order of 2 with respect to a reactant, doubling the concentration of that reactant will result in a:

Accepted Answer

Quadrupling of the reaction rate

Answer

Doubling of the reaction rate

Answer

Tripling of the reaction rate

Answer

No change in the reaction rate

Question 60

Which step in a reaction mechanism is responsible for determining the overall rate of the reaction?

Accepted Answer

The slowest step

Answer

The fastest step

Answer

An intermediate step

Answer

The overall reaction itself

Question 61

Which of the following reactions is heterogeneous, occurring in different phases?

Accepted Answer

Combustion of methane gas

Answer

Neutralization of an acid by a base in solution

Answer

Reaction between sodium and chlorine to form sodium chloride

Answer

Decomposition of hydrogen peroxide in a homogeneous solution

Question 62

Which of the following describes the role of a catalyst in a chemical reaction?

Accepted Answer

Catalysts provide an alternative pathway with a lower activation energy, speeding up the reaction.

Answer

Catalysts are consumed in the reaction.

Answer

Catalysts only work in solid form.

Answer

Catalysts can be used only once.

Question 63

A reaction rate is found to be proportional to the square of the concentration of a reactant. What is the order of the reaction with respect to that reactant?

Accepted Answer

2

Answer

1

Answer

0.5

Answer

-1

Question 64

A reaction between dilute hydrochloric acid and magnesium ribbon produces hydrogen gas. How will increasing the concentration of the acid affect the reaction rate?

Accepted Answer

Increase the rate

Answer

Decrease the rate

Answer

Have no effect on the rate

Answer

Reverse the reaction