Grade 8 Science
Name: _________________________
Group Members: _________________________________________________________
Investigating the Rate of Chemical Reactions
Overview: The rate at which a chemical reaction proceeds is explained by the Collision Theory.
The Collision Theory states that molecules must collide with sufficient energy in order to
combine chemically. The rate at which the chemical reaction proceeds depends on 4 factors:
concentration of reactants, presence of a catalyst, surface area of reacting substances, and
temperature.
Purpose: To investigate the effect of temperature on the rate of a chemical reaction.
Hypothesis:
When surface area is kept constant, this experiment will show that a reaction will proceed
__________________ when temperature is increased.
Materials:
4 seltzer tablets
4 plastic cups
Room-temperature water, cold water, warm water
Thermometer
Stop watch
Procedure:
Part A.
1. Obtain all materials except beaker with hot water.
2. Place room temp water into a cup up to the top line.
3. Place ice water into a second cup up to the line.
4. Record temperature of those 2 cups before obtaining the hot water.
5. Obtain hot water and take temperature ( Make sure you are ready to proceed right after this!)
6. Have partners prepare to drop one WHOLE tablet into each cup as the timer is started.
7. Record the elapsed time when each fully has dissolved. There is no need to turn off the
timer- call off the time and record it and keep the timer going for the next one to dissolve.
8. Repeat the process with the fourth cup using room temp water but break the tablet into
several pieces (minimum 4).
GROUP DATA Whole.
Temperature
Time
to
(seconds)
GROUP DATA Boken
Dissolve Temperature
Time
to
(seconds)
RT
RT
Cold
XXXXXXXX
XXXXXXXX
Warm
XXXXXXXX
XXXXXXXX
Dissolve
CLASS DATA Room Temperature
Group
1
2
3
4
5
6
7
Class Average
Time to Dissolve (seconds)
CLASS DATA Cold
Group
1
2
3
4
5
6
7
Class Average
Time to Dissolve (seconds)
CLASS DATA Warm
Group
1
2
3
4
5
6
7
Class Average
Time to Dissolve
(seconds)
Name:_______________________
What factor were you testing in part one of this experiment?
What is the manipulated variable for this part one of this experiment?
What is the responding variable?
Write a relationship statement (conclusion) for part one of this experiment.
What factor were you testing in part 2 of this experiment?
What is the manipulated variable?
What is the responding variable?
Write a relationship statement ( conclusion) for part 2 of this experiment.