Stoichiometry Lab – The Penny and HCl
Procedure Day 1:
1. Obtain a pre-cut penny from 1983 or later (these pennies are mostly Zn)
2. Take the mass of the penny on one of the scales. Record in data section.
3. Place the penny in a beaker and add enough 6M HCl to cover the penny
4. Put you and your partners name on the beaker with sharpie. Place them in fume hood.
5. Predict the reaction for the Zn penny and the HCl. (hint: it is a single replacement and one of the products is Hydrogen gas; make sure to balance this reaction also) Record in data section.
Procedure Day 2:
1. Wash the penny off with water (carefully and with tongs)
2. Dry the penny carefully over the Bunsen burner using tongs. DO NOT PUT THE PENNY DIRECTLY IN THE FLAME!!
3. When the penny is dry, take the mass of it on one of the scales. Record in data section.
Data
Mass of penny before: ______
Mass of penny after: ______
Balanced equation:______
Calculations
1. Calculate the mass of copper in the penny. (mass of penny after)
2. Calculate the mass of zinc in the penny. (mass before – mass after)
3. Using your mass data, determine the percent composition of Zn and Cu in the post 1983 penny.
Mass of Zn x 100 = % Zn
Initial Mass
Mass of Cu x 100 = % Cu
Initial Mass
4. What mass of H2 was produced by the penny?
HINT: Use the balanced equation from Day 1 and the mass of Zn (Questions #2) as the given mass.
5. What mass of ZnCl2 was formed in the reaction?
HINT: Use the balanced equation from Day 1 the mass of Zn (Questions #2) as the given mass.
6. What mass of HCl is used in this reaction?
HINT: Use your mass of Zn from Lab Questions #2 as the given mass.
Stoichiometry Lab – The Penny and HCl
Procedure Day 1:
1. Obtain a pre-cut penny from 1983 or later (these pennies are mostly Zn)
2. Take the mass of the penny on one of the scales. Record in data section.
3. Place the penny in a beaker and add enough 6M HCl to cover the penny
4. Put you and your partners name on the beaker with sharpie. Place them in fume hood.
5. Predict the reaction for the Zn penny and the HCl. (hint: it is a single replacement and one of the products is Hydrogen gas; make sure to balance this reaction also) Record in data section.
Procedure Day 2:
1. Wash the penny off with water (carefully and with tongs)
2. Dry the penny carefully over the Bunsen burner using tongs. DO NOT PUT THE PENNY DIRECTLY IN THE FLAME!!
3. When the penny is dry, take the mass of it on one of the scales. Record in data section.
Data
Mass of penny before: ______
Mass of penny after: ______
Balanced equation:______
Calculations
1. Calculate the mass of copper in the penny. (mass of penny after)
2. Calculate the mass of zinc in the penny. (mass before – mass after)
3. Using your mass data, determine the percent composition of Zn and Cu in the post 1983 penny.
Mass of Zn x 100 = % Zn
Initial Mass
Mass of Cu x 100 = % Cu
Initial Mass
4. What mass of H2 was produced by the penny?
HINT: Use the balanced equation from Day 1 and the mass of Zn (Questions #2) as the given mass.
5. What mass of ZnCl2 was formed in the reaction?
HINT: Use the balanced equation from Day 1 the mass of Zn (Questions #2) as the given mass.
6. What mass of HCl is used in this reaction?
HINT: Use your mass of Zn from Lab Questions #2 as the given mass.