CHILL OUT
Materials
50 ml graduate cylinder
250 ml beaker
Balance scale
Citric acid solution
Baking soda
6 M hydrochloric acid solution (CAUTION)
Goggles
Gloves
Apron
Magnesium ribbon
Thermometer
Glass stirring rod
Styrofoam cup
Be sure to wear goggles at all times and notify your teacher in case of an accident.
CAUTION: Hydrochloric acid is caustic. Do not spill it on your skin or clothing.
Part A
1. Place a Styrofoam cup inside a 250 ml beaker. Measure 30 ml of citric acid
solution and add it to the Styrofoam cup. Place a thermometer into the solution.
Record the temperature in the table.
2. Measure 10.0 g baking soda. Add the baking soda to the citric acid solution and
stir with a glass stirring rod. Record the temperature every 20 seconds for about 5
minutes. Stop recording the temperature when it begins to rise. Use graph paper to
record the results. Connect the data points using a blue map pencil.
3. Flush solution down the sink with water. Rinse the thermometer and dispose of
the cup as directed by the teacher.
Questions:
1. How can you tell that a chemical reaction is taking place?
2. Is the reaction endothermic or exothermic? Why?
Part B
1. Place a Styrofoam cup inside a 250 ml beaker. Measure 30 ml of hydrochloric
acid and add it to the Styrofoam cup. Place a thermometer into the solution.
Record the temperature in the table.
2. Obtain a piece of magnesium metal (approximately 0.1 g). Gently place the
magnesium metal into the cup of hydrochloric acid. CAUTION: Do not
breathe the vapors! Record the temperature every 20 seconds until the
temperature begins to drop. Use graph paper to record the results. Connect the
data points using a red map pencil.
3. Flush solution down the sink with water. Rinse the thermometer and dispose of
the cup as directed by the teacher.
Questions:
1. How can you tell that a chemical reaction is taking place?
2. Is the reaction endothermic or exothermic? Why?
3. Which reaction took place at a greatest rate? Explain your answer using the graph.