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Lab # ________
Worksheet – Speed It Up
Background: Reaction rate means how quickly or slowly a reaction takes place. To control the rate
of reaction, it is helpful to know what causes a reaction to speed up or slow down. There are four
factors that affect reaction rates: concentration, temperatures, surface area and the presence of a
catalyst. In this lab, we will look at two of these factors, concentration and temperature.
Concentration tells how much of a substance has dissolved in a solution. Do not confuse
concentration with strength. Concentration is how many particles, not how strong the particles are.
Molarity is how much of a substance is in solution, so the more moles the higher the concentration.
A 3M acid is three times more concentrated then a 1M acid. Temperature is the measure of motion
of the particles of a substance. As the temperature increases, the particles move faster and come in
contact more often. In order for two substances to react, the particles must collide with each other so
increased motion of the particles means there will be increased contact of the particles.
Purpose: To observe the effect of concentration and temperature on the rate of a chemical reaction.
Materials:
safety goggles
timer/watch
5 large test tubes
test tube rack
10 ml graduated cylinder
thermometer
ice water bath
hot pot/water
HCl (3M)
HCl (1M)
Mg ribbon 5-2cm pieces
MSDS Information:
Hydrochloric acid – Corrosive material. Avoid contact with skin, eyes, and mucous
membranes. Keep away from strong oxidants, bases, alkali metals, copper, copper alloys, and
aluminum. Avoid breathing vapor. Practice strict hygiene when using this material. Wash affected
parts with copious quantities of water.
Magnesium – Flammable solid. Will react with water and acids to release flammable
hydrogen. Do not use a hydrous (like CO2) extinguisher. Use dry sand or a Type 3 fire extinguisher.
Avoid directly viewing burning magnesium. Intense white flame may cause eye injury.
NOTE: Before beginning part one, measure 5 ml of 1M hydrochloric acid into test tube #3 and put
it in the hot water bath. Measure 5 ml of 1M hydrochloric acid into test tube #4 and put it in the cold
water bath.
Procedure: Part One – Concentration
A. Measure 5 ml of 3M hydrochloric acid into test tube #1.
B. Fold one piece of the magnesium into a “V” shape.
C. Drop this piece of magnesium into test tube #1. Record the time needed for a complete reaction in
Table 1.
D. Measure 5 ml of 1M hydrochloric acid into test tube #2.
E. Fold one piece of the magnesium into a “V” shape.
F. Drop this piece of magnesium into test tube #2 and record the time needed for a complete
reaction in Table 1.
G. Dispose of the acid solution in the waste receptacle. Wash and rinse the test tubes and the
graduated cylinder.
Procedure: Part Two – Temperature
H. Obtain test tube #3 from the hot water bath.
I. Place one folded piece of magnesium into this test tube and record the time needed for a complete
reaction in Table 2.
J. Obtain test tube #4 from the cold water bath.
K. Place one folded piece of magnesium into this test tube and record the time needed for a complete
reaction in Table 2.
L. Pour 5 ml of room-temperature 1M hydrochloric acid into test tube #5.
M. Place one folded piece of magnesium into this test tube and record the time needed for a
complete reaction in Table 2.
N. Wash and rinse all equipment.