Journal Carbonate Lab

Thanks to K. Holland

Questions:

  1. How will our senses tell us that a chemical reaction with hydrochloric acid (HCl) is occurring?
  2. What are the substances in this lab that respond to HCl?
  3. What about the chemical makeup of the reacting substances is similar?

Background:

The chemicals that make up a substance determine the properties of that substance. The mineral quartz has a chemical formula of SiO2 (silicon dioxide). SiO2 is a clear substance that is very hard and very brittle (it breaks instead of bending). Glass, which is made up of SiO2, is also clear, hard, and brittle. These are all physical properties that can be observed without changing the chemical make-up of the substance.

SiO2 also has chemical properties that can only be observed by making it interact with other chemicals. There are some substances that have the chemical property of being reactive to acid. Some substances undergo a chemical change when they are combined with an acid such as hydrochloric acid (HCl). This lab explores the chemical property of being reactive to acid.

Predictions / Hypotheses:

  1. If acid is added to a reactive substance, then we would observe ...
  2. The following substances will react to acid:
  3. Substances that react with acids are similar ...

Equipment:

The following materials are needed:
hydrochloric acid sugar seashells chalk
safety goggles eggshells quartz baking powder
waste container Alka-seltzer® dried peas plastic
petri dish dietary supplement baking soda
wash bottle washing soda calcite

Conclusion:

Read and follow the lab report format for conclusions. Remember that you have three hypotheses to discuss.

Procedure - Part 1:     Safety goggles must be worn at all times during this lab!

  1. Obtain a dry petri dish from the supply area.
  2. Place a piece of calcite in the petri dish. Use the scoop to put a small amount of washing soda and baking soda in the petri dish.
  3. Put ONE or TWO DROPS of acid on each substance by holding the pipette vertically so that the tip is about one centimeter above the substance.
  4. Record the reaction.
  5. Use the wash bottle to rinse the remains of the experiment into the waste container.
  6. Turn the petri dish upside down to dry.

Data Table 1: Reactivity to Acid Part 1

Location Substance Reaction to Acid Chemical Formula
1 Calcite
 
CaCO3
 
2 Baking soda
 
NaHCO3
 
3 Washing soda
 
Na2CO3
 

Procedure - Part 2:     Safety goggles must be worn at all times during this lab!

  1. Obtain a dry petri dish from the supply area.
  2. Sample each remaining substance from the supply area by putting a small amount / piece in the petri dish.
  3. Put ONE or TWO DROPS of acid on each substance by holding the pipette vertically so that the tip is about one centimeter above the substance.
  4. Record the reaction.
  5. Use the wash bottle to rinse the remains of the experiment into the waste container.
  6. Turn the petri dish upside down to dry.
  7. Using the knowledge gained in Part 1 of this lab, what chemical components might be present in the substances you just tested with HCl? Record the formula of those chemical components in the chemical formula column of table 2.

Data Table 2: Reactivity to Acid Part 2

Location Substance Reaction to Acid Chemical Formula
1 Sugar
 

 
2 Egg shell
 

 
3 Sea shell
 

 
4 Quartz
 

 
5 Dried peas
 

 
6 Chalk
 

 
7 Plastic
 

 
8 Baking powder
 

 
9 Alka-seltzer®
 

 
10 Dietary supplement