Name________________________ Per_______
Factors Affecting the Rate of Chemical Reactions Worksheet
Directions: READ pages 212-215 in your text book Physical Science: Concepts in Action and answer the following
questions;
1. Provide definitions for the following terms;
Catalyst
a substance that causes or accelerates a chemical reaction without itself being
affected.
Reaction Rate
the speed at which a chemical reaction proceeds
2. Answer the following questions using COMPLETE SENTENCES (a and b);
a.
In your own words, describe what effect cooling has on the frequency at which particles of reactants
can collide. Provide a real life example as to how we use temperature to alter reactions for our benefit.
cooling slows down the particles, so less collisions occur
using a fridge to keep food from spoiling
b. In your own words, describe why an increase in concentration can result in a change in the rate of a
reaction. Provide a real life example as to how we adjust concentration to adjust a reaction for our
benefit.
increasing concentration increases the number of particles, so more collisions occur
have a higher dose of a medication to help fight infection
c.
Complete the following table by indicating whether each of the following scenarios would either
increase or decrease the rate of reaction. The first one has been done for you. (4 mks for correctly
completing the table)
Scenario
Adding heat
Removing heat
Adding a catalyst
Diluting a solution
Removing an enzyme (catalyst)
Lowering the temperature
Increasing the temperature
Decreasing the surface area
Increasing the concentration of a solution
Breaking a reactant down into smaller pieces
Increase or Decrease
Increase
decrease
increase
decrease
decrease
decrease
increase
decrease
increase
increase
HANDOUT
Name________________________ Per_______
d. Complete the following table by indicating which factor would have the greatest impact on the rate of
reaction. Choose from concentration, temperature, surface area or catalyst. The first one has been
done for you. (3 mks for correctly completing the table)
Scenario
Factor that has the greatest impact on
the rate of reaction.
Blowing air on a campfire to help get it going.
Raw carrots are cut into thin slices for cooking.
Protein is broken down in the stomach by the enzyme pepsin.
A Woolly Mammoth is found, perfectly preserved, near the Arctic
circle.
More bubbles appear when a concentrated solution of hydrochloric acid
is added to a magnesium strip than when a dilute solution of the acid is
added.
Exhaust from a car engine passes through a catalytic converter
changing most of the poisonous nitrogen oxides into nitrogen gas and
oxygen gas.
A dust explosion occurs in a saw mill.
concentration
surface area
catalyst
temperature
concentration
catalyst
concentration
3. Use the terms to correctly fill in the blanks.
Terms
catalyst
temperature
collisions
concentration
dilute
1.
energy
heat
rate of reaction
surface area
A freshly exposed surface of metallic sodium tarnishes almost instantly if exposed to air and moisture,
while iron will slowly turn to rust under the same conditions. In these two situations, the
rate of reaction
refers to how quickly or slowly reactants turn into products.
__________________
heat
2. Adding _________________________
will increase the rate of reaction because this causes the
particles of the reactants to move more quickly, resulting in more collisions and more
energy
______________________.
3. Removing heat will lower the ____________________,
causing the particles of the reactants to slow
temperature
down, resulting in less frequent collisions.
concentration
4. ___________________ refers to how much solute is dissolved in a solution. If there is a greater
concentration of reactant particles present, there is a greater chance that __________________
among
collisions
them will occur. More collisions mean a higher rate of reaction.
dilute
acid solution because there
5. A concentrated acid solution will react more quickly than a _______________
are more molecules present, increasing the chance of collisions.
surface area
6. Grains of sugar have a greater ______________________
than a solid cube of sugar of the same mass,
and therefore will dissolve quicker in water.
catalyst
7. A ______________________,
for example an enzyme, is used to speed up a chemical reaction but is not
used up in the reaction itself.
HANDOUT
(b)
5O ºC
O ºC
HANDOUT
Name________________________ Per_______
4. . Identify which situation (X or Y) would have a higher reaction rate. Then state the factor that affected the rate of reaction in each
situation (concentration, surface area, catalyst, temperature).
Situation X
Situation Y
Situation with a higher
Factor affecting the
reaction rate (X or Y)
rate of reaction
(a)
1 g of sugar (cubes)
1 g of sugar (grains)
concentration
temperature
Y
X
enzyme added
Twigs
low number of particles =
few collisions
no enzyme added
Logs
HANDOUT
Y
(e)
(d)
(c)
Name________________________ Per_______
high number of particles = more collisions
concentration
catalyst
surface area
X
X