Rates of Reaction questions

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Rates of Reaction question collection

Review Rates of Reaction questions for Chemistry, with correct answers shown and coverage across what does reaction rate describe; choosing which change usually increases reaction rate; explaining why does increasing temperature often speed up a reaction.

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Question 1

What does reaction rate describe?
  1. How quickly reactants become products
  2. How completely reactants become products
  3. How much product forms at completion
  4. How much energy the reaction transfers

Question 2

Which change usually increases reaction rate?
  1. Raising the temperature
  2. Lowering the concentration
  3. Using larger solid pieces
  4. Reducing the gas pressure

Question 3

Why does increasing temperature often speed up a reaction?
  1. More particles collide with enough energy
  2. Particles become heavier
  3. Fewer collisions happen each second
  4. The reaction stops at a lower temperature

Question 4

Marble chips react with acid. Which gives the fastest rate?
  1. Small powdered marble chips
  2. One large marble chip of the same mass
  3. Marble chips kept in a freezer
  4. Marble chips in pure water

Question 5

How does higher solution concentration usually affect reaction rate?
  1. It increases the rate
  2. It decreases the rate
  3. It leaves the rate unchanged
  4. It changes the products instead

Question 6

What does a catalyst do?
  1. Speeds the reaction and remains unchanged
  2. Speeds the reaction and becomes a product
  3. Slows the reaction and remains unchanged
  4. Increases the final amount of product

Question 7

What happens to manganese dioxide after it catalyses hydrogen peroxide decomposition?
  1. It remains chemically unchanged
  2. It becomes oxygen gas
  3. It becomes part of the water
  4. It changes into hydrogen peroxide

Question 8

Which is a valid way to measure reaction rate when a gas is made?
  1. Measure gas volume every set time interval
  2. Measure mass once at the start
  3. Count atoms directly by eye
  4. Measure beaker colour every second

Question 9

On a graph of gas volume against time, what does a steeper slope mean?
  1. A faster reaction rate
  2. A lower concentration of reactants
  3. The reaction has stopped
  4. No products are being formed

Question 10

Why does a non-reversible reaction eventually stop?
  1. A limiting reactant is used up
  2. The catalyst becomes a product
  3. The products lose all kinetic energy
  4. The activation energy becomes infinite

Question 11

How does a catalyst affect a reaction that goes to completion?
  1. Same product amount in less time
  2. More product in the same time to completion
  3. Less product in more time
  4. Same product amount in more time

Question 12

How does diluting hydrochloric acid affect its reaction with magnesium?
  1. It usually slows the reaction
  2. It usually speeds the reaction
  3. It leaves collision frequency unchanged
  4. It changes magnesium into a catalyst

Question 13

When testing concentration's effect on rate, which variable should be kept constant?
  1. Temperature
  2. Concentration
  3. Reaction time
  4. Product volume

Question 14

Two reactions each make 40 cm³ of gas. Which is faster?
  1. The one taking 20 seconds
  2. The one taking 40 seconds
  3. Both have the same rate
  4. The time does not show rate

Question 15

If a reaction goes to completion, what is true about the limiting reactant?
  1. It has been completely used up
  2. Its amount increases over time
  3. It becomes the catalyst
  4. It stays unchanged throughout

Question 16

Why does a reaction often slow as it proceeds?
  1. Fewer reactant particles remain to collide
  2. Product particles become reactants
  3. The catalyst is used up as fuel
  4. Temperature must rise during every reaction

Question 17

When a colour-change reaction reaches a chosen shade, which measurement compares its rate?
  1. Time taken
  2. Mixture mass
  3. Mixture volume
  4. Mixture temperature

Question 18

A gas syringe reads \(30\,\mathrm{cm^3}\) after \(15\,\mathrm{s}\). What is the average gas production rate?
  1. \(2\,\mathrm{cm^3\,s^{-1}}\)
  2. \(0.5\,\mathrm{cm^3\,s^{-1}}\)
  3. \(15\,\mathrm{cm^3\,s^{-1}}\)
  4. \(45\,\mathrm{cm^3\,s^{-1}}\)

Question 19

Which condition gives the most frequent particle collisions in a gas reaction?
  1. High pressure with the same amount of gas
  2. Low pressure with the same amount of gas
  3. Lower temperature and larger volume
  4. Using a larger reaction flask at lower concentration

Question 20

In the reaction \(\mathrm{CaCO}_3 + 2\mathrm{HCl} \to \mathrm{CaCl}_2 + \mathrm{CO}_2 + \mathrm{H}_2\mathrm{O}\), what does a faster fizzing rate indicate?
  1. CO2 is being produced more quickly
  2. Less CO2 is produced overall
  3. No acid is reacting
  4. The reaction has reached equilibrium and stopped

Question 21

What is activation energy?
  1. The minimum energy needed for a successful collision
  2. The total energy stored in all reactants
  3. The energy released by every collision
  4. The kinetic energy of the catalyst

Question 22

How does a catalyst increase reaction rate?
  1. It provides a pathway with lower activation energy
  2. It raises every particle's kinetic energy
  3. It increases the reactant concentration
  4. It makes collisions release less energy

Question 23

Why can higher concentration increase reaction rate?
  1. More reactant particles collide each second
  2. Each reactant particle becomes larger
  3. The activation energy automatically falls
  4. The products collide less often

Question 24

Why does powdered solid often react faster than lumps?
  1. It has a larger surface area
  2. It has more particles in total
  3. It changes the activation energy
  4. It has a higher concentration

Question 25

When testing surface area's effect on rate, which variable should change?
  1. The size of the solid pieces
  2. The acid concentration
  3. The reaction temperature
  4. The mass of solid used

Question 26

When reacting gases are compressed at constant temperature, what happens to collision frequency?
  1. It increases
  2. It decreases
  3. It stays the same
  4. It falls to zero

Question 27

Which form of the same solid usually reacts slowest?
  1. One large lump
  2. Fine powder
  3. Small chips
  4. Thin shavings

Question 28

Which measurement can track a reaction that releases gas into the air?
  1. Decrease in mass over time
  2. Initial mass before reaction
  3. Final mass without a time
  4. Atomic mass of the gas

Question 29

Why does stirring often increase reaction rate?
  1. It brings reactant particles together more often
  2. It lowers the concentration of reactants
  3. It reduces the surface area of solids
  4. It removes kinetic energy from particles

Question 30

What does a horizontal section on a gas-volume graph show?
  1. No more gas is being produced
  2. Gas is being produced faster
  3. Gas volume is falling steadily
  4. The reaction temperature is rising

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Review Rates of Reaction questions for Chemistry, with correct answers shown and coverage across what does reaction rate describe; choosing which change usually increases reaction rate; explaining why does increasing temperature often speed up a reaction.

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