Which sample is a pure substance? a. a test tube of zinc oxide
b. a container of zinc and oxygen
c. a flask of pond water
d. a jar of soil

Write a hypothesis that answers the lesson question, “while observing a chemical reaction, how can you tell which reactant is limiting? ” hypothesis: if a substance is the limiting reactant, then . . because . .

In the 1800s, one of the statements in john dalton's atomic theory was that atoms are indivisible. later experimental evidence led to the discovery of subatomic particles such as neutrons, electrons, and protons. what happened to the indivisible atom part of dalton's atomic theory, and why?

Why is permeable soil best for plants that need a lot of drainage?