Lab: Types of Reactions Answers

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Which of the following best explains why you sanded the copper wire before burning it?

What signs of a chemical reaction did you observe during the lab? Check all that apply.

Which of the following best explains why you put KI and Pb(NO3)2 into two separate test tubes before mixing them?

Check all of the reasons that you included in your answer.Copper oxide is the only product, and it contains copper and oxygen.One of the reactants is copper, so the other reactant must be oxygen.The copper metal must have combined with something in the air.

When you burned copper, the product copper oxide appeared on the wire. Besides copper, the other reactant is .

Select all steps below that you followed to practice laboratory safety during the experiment.

As a cake bakes, sodium bicarbonate reacts with acids in the cake. The bicarbonate ion and the anion in the acid change places to make carbonic acid. The carbonic acid then breaks down to produce carbon dioxide bubbles that make the cake rise. Check all of the reactions that occurred.

Silver tarnishes as silver metal reacts with hydrogen sulfide, H2S, in the air. In this reaction, dark silver sulfide, Au2S, covers the surface of silver. When silver is polished, this coating of silver sulfide can be removed from the surface. This makes the silver shiny again. Enter the coefficients that balance the tarnishing reaction equation. (Type 1 for no coefficient.)

When silver tarnishes, a reaction happens.

Explain how you know it must be oxygen. Where did the oxygen come from?

After you finished the experiment, which of the following did you do?