Worksheet: Reaction Rate

In this worksheet, we will practice describing the rate of a chemical reaction and explaining the effect of heat on the rate of reaction using the collision theory.


Collision theory states that chemical reactions occur when particles (e.g., atoms or molecules) collide. Which of the following, according to collision theory, does not play a part in determining the rate of a reaction?

  • AThe activation energy for the reaction
  • BThe number of particles analyzed
  • CThe frequency with which particles collide
  • DThe energy with which particles collide


Which one of the following would not increase the rate of a reaction, according to collision theory?

  • AIncreasing the pressure
  • BUsing a catalyst
  • CIncreasing the surface area of particles
  • DIncreasing the temperature
  • EUsing a differently shaped container with the same volume


Which one of the following would not increase the rate of a reaction, according to collision theory?

  • AA higher activation energy
  • BA higher particle concentration
  • CParticles colliding more frequently
  • DA higher temperature
  • EParticles having more energy


When two reactive particles collide, there are many factors that affect whether a reaction will occur.

Which of the following factors does not have an effect?

  • AThe energy of the collision
  • BThe activation energy
  • CThe orientations of particles
  • DThe temperature
  • EThe number of products


When lightning strikes, molecules of oxygen (O)2 and nitrogen (N)2 in the atmosphere are given enough energy to combine together to form nitric oxide (NO). Under normal conditions, oxygen and nitrogen molecules collide but do not react. What does this suggest about the reaction?

  • AIt cannot be performed without a catalyst.
  • BIt is irreversible.
  • CIt is reversible.
  • DIt is catalyzed by lightning.
  • EIt has a very large activation energy.


For a simple reaction between gases A and B, which of the following temperatures will give the highest reaction rate?

  • A0C
  • B50C
  • C100C
  • D25C
  • E75C


When a reaction mixture is heated, the particles collide more frequently. Which of the following is the best explanation of this effect?

  • AThe particles get larger.
  • BThe particles get closer together.
  • CThe particles break apart.
  • DThe particles exert stronger attractive forces.
  • EThe particles move faster.


In the following reaction, the rate of sulfur formation was determined to be 0.002 g/s: NaSO()+2HCl()2NaCl()+HO()+SO()+S()22322aqaqaqlgs How much sulfur was formed after 5 minutes?


In aqueous solutions, molecular bromine reacts with methanoic acid (HCOOH) as shown: Br()+HCOOH()2Br()+2H()+CO()2+2aqaqaqaqaq An experiment was designed to study the kinetics of the reaction. The initial Br2 concentration in the reaction vessel was 0.0120 mol⋅dm−3, and after 50 seconds, the value had dropped to 0.0101 mol⋅dm−3 .

What is the average rate of the reaction over the first 50 seconds? Give your answer to 2 decimal places.

  • A1.90×10 mol⋅dm−3/s
  • B2.42×10 mol⋅dm−3/s
  • C1.90×10 mol⋅dm−3/s
  • D4.42×10 mol⋅dm−3/s
  • E3.80×10 mol⋅dm−3/s


What is the name of the theory that explains why chemical reactions can only take place when reacting particles collide with each other with sufficient energy?

  • ACollision theory
  • BRate theory
  • CActivation theory
  • DReaction theory
  • EChaos theory


Which of the following reactions is most likely to have the fastest rate of reaction?

  • AThe setting of epoxy resins and other similar glues.
  • BThe cooking of an egg.
  • CThe carbonization of dead plants and animals into fossil fuels.
  • DThe explosive reaction between hydrogen and oxygen gases.
  • EThe rusting of iron.


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

  • AThe pressure of reacting gases
  • BThe surface area of solid reactants
  • CThe reversibility of the reaction
  • DThe concentrations of reactants in a solution
  • EThe presence of a catalyst


Fill in the blank: After particles collide, the minimum amount of energy they must have in order to react is referred to as the .

  • Aexothermic energy
  • Binitiation energy
  • Ccollision energy
  • Dactivation energy
  • Elaunch energy


The reaction between warm hydrochloric acid and magnesium has a faster rate of reaction than the reaction between cold hydrochloric acid and magnesium. Which statement explains this observation?

  • AThe particles are moving faster and with greater energy.
  • BThe particles are more concentrated and have a greater mass.
  • CThe particles are more concentrated and have greater energy.
  • DThe particles are moving faster and have a greater surface area.
  • EThe particles are moving faster and have a greater mass.


Iron filings will not react with powdered sulfur when mixed at room temperature. If a mixture of iron filings and powdered sulfur is heated strongly using a Bunsen burner, a reaction takes place.

Which statement best describes why the heated mixture reacts?

  • AThe reaction is exothermic.
  • BThe Bunsen flame acts as a catalyst.
  • CThe iron and sulfur particles have collided.
  • DThe surface area of the powders has increased.
  • EThe required activation energy has been achieved.


When excess hydrochloric acid reacts with calcium carbonate, carbon dioxide is produced. If 5 grams of calcium carbonate is consumed in 3 minutes and 20 seconds, what is the average rate of reaction?

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