Single Replacement Reactions: Turning Iron into Copper
One type of chemical reaction is the single replacement reaction, also called the displacement reaction. In this type of reaction, one element replaces a similar element in a compound. The general formula for a single replacement reaction is
- A + BC → AC + B
Reactants (what you begin with) are shown on the left side of the arrow. In this case, A is an element and BC is a compound. Products (what you make) are shown on the right side of the arrow. AC is the new compound, and B is the new element. In this activity you will observe a single replacement reaction.
Safety goggles; Small resealable freezer bag containing 2 teaspoons of copper sulfate powde; Small cup containing 2 tablespoons of water; Marble-size piece of steel wool; Paper towel
Place 2 teaspoons of copper sulfate in a resealable plastic bag. Put 2 tablespoons of water into a small cup.
- Put on your safety goggles.
- Your teacher has placed 2 teaspoons of copper sulfate in a plastic bag. The chemical formula for this compound is CuSO4.
- Open the bag and pour the water from the cup into the bag. Zip the bag closed. Gently knead the bottom of the bag to mix the contents. Observe the color of the liquid produced. You now have a copper sulfate solution.
- Open the bag and drop the piece of steel wool into the liquid. Zip the bag and observe what happens over the next couple of minutes. Steel wool is made of the element iron. The symbol for iron is Fe.
- Note any changes to the solution and the solid in the bag.
- What changes occurred in the liquid? What changes occurred in the solid?
- If this were a single replacement reaction and your reactants were copper sulfate and iron, what would your two products be?
- The copper sulfate solution was originally blue. After the reaction occurred, the solution turned a yellow-green color. The steel wool was originally gray. After the reaction, the steel wool took on a copper color.
- Iron sulfate and copper.
Predict the products of this single replacement reaction:
- aluminum + copper (II) chloride → __________
Ask your teacher if you can observe this by adding a piece of aluminum foil to a solution of copper (II) chloride.