Ella set up an experiment to investigate one of her questions. She set up one test tube to look like Figure 1. She set up another test tube similar to Figure 1 but without
a lamp, and placed it in a dark closet. A day later, Ella checked the water level in
each test tube.

What was the test (independent) variable in the student's experiment?
A. The amount of light.
B. The amount of time.
C. The water level in the test tube.
D. The amount of oxygen released.

Idid a lab for chemistry where we put nails in a copper (ii) chloride solution. 1. why did the reaction stop? which reactant was used up? how do you know? 2. describe what was happening to the atoms of iron and copper during the reaction. what is this type of reaction called? 3. what would happen to the ratio of copper to iron if you had placed more nails in the beaker? if you had let the reaction go for less time? 4. what is the accepted ratio of copper atoms to iron atoms in this reaction? account for differences between your experimental value and the accepted value. write the balanced equation for the reaction.