Mole Ratios and Chemical Reactions Lab Activity
Introduction:
In this experiment we will study the single replacement reaction of silver from silver nitrate. The
experiment will be set up so that you can observe the various steps. This lab will be done in this fashion
because silver nitrate is extremely expensive.
The data you obtain supports the concept of reacting mole ratios in chemical reactions. An outline of
the procedure for the experiment is given below. Go to each station to collect the necessary data and
observations.
A massed piece of copper wire is allowed to react with an aqueous solution of silver nitrate. The
product is dried and massed. The mole ratio of reactant to product is determined and the balanced equation for
the reaction can be deduced. (You will determine whether the copper compound formed after the reaction is
copper (I) or copper (II).
Procedure
Station 1
1. Obtain about 30 cm of copper wire. Form a coil by wrapping the wire around a test tube. Leave a
length of wire for a handle and stretch the coil so the wire will be in the solution. Mass the copper coil.
2. Mass a clean and dry beaker.
3. Find the mass of a test tube filled with solid silver nitrate.
4. Fill the beaker about half-way with distilled water and add the solid silver nitrate. Stir gently until the
silver nitrate is completely dissolved. Mass the empty test tube.
Station 2
5. Place the copper wire into the solution.
6. Allow the reaction to take place for 24 hours.
Station 3
7. Observe what has happened in the beaker.
Station 4
8. Shake the crystals off the coil and lift the coil from the solution. Rinse the coil with distilled water,
letting the water run into the beaker. Allow the coil to dry and mass it.
9. Let the crystals in the beaker settle. Carefully decant (pour off) the excess liquid into another beaker.
Add 5 mL of silver nitrate solution to the crystals in the beaker and swirl gently until any flecks of
copper disappear. Carefully decant the liquid off of the crystals. Repeat this washing procedure three
times.
10. Add 5 mL of distilled water to the crystals in the beaker and swirl gently. Carefully decant the water off
of the crystals. Repeat this washing procedure three times.
11. Dry the crystals and beaker in a drying oven. Allow the beaker to cool and mass the beaker and its
contents.
Calculations:
1. Calculate the mass of copper that reacted.
2. Calculate the moles of copper that reacted.
3. Determine the mass of product (this is silver).
4. Calculate the moles of silver produced.
5. Determine the mole ratio of copper to silver.
Questions:
1. What evidence do you see for a chemical reaction?
2. Write the balanced chemical equation for copper and silver nitrate reacting to form copper (I) nitrate.
3. Write the balanced chemical equation for copper and silver nitrate reacting to form copper (II) nitrate.
4. Which equation represents the reaction that occurred in Experiment B? Be sure to support your answer
with experimental evidence. (Hint: Compare the mole ratio from #5 of your calculations to the
equations you wrote in questions 3 and 4.)
5. Challenge Question: Why is it necessary to do the silver nitrate washes in step #9?
6. Why is it necessary to do the water washes in step #10?
Name: _____________________________________________
Station # Observations
1) AgNO3: very small, tan crystals
in a test tube
1
2) Cu: 1mm thick reddish-brown
wire in a coil shape
Copper coil is in colorless, clear
2
solution. No evidence of a chemical
reaction.
Solution is blue. Copper coil is
3
covered in a grayish-silver
precipitate.
dry, small, spiky crystals of silver
metal are contained in a beaker.
4
copper coil is more dull and has
some dark gray coloring in places.
Data
Mass of test tube: 6.43 g
Mass of test tube + AgNO3(s): 11.19 g
Mass of Cu coil before reaction: 5.63 g
Mass of empty beaker: 42.81 g
No data.
No data.
Mass of Cu coil after reaction: 4.74 g
Mass of beaker and dried contents: 45.83 g
Calculations: Show all work with units. Answers must have correct units and significant figures.
1. Mass of copper reacted:
2. Moles of copper reacted:
3. Mass of product (silver):
4. Moles of silver produced:
5. Mole ratio of copper to silver:
Answer lab questions on the back of this sheet in complete sentences.