Support Reaction Claims With Evidence Practice Test

A student claims: "Iron rusted because it reacted with oxygen in the air."

Evidence:

1. After a week, a reddish-brown coating formed on the iron nail.

2. The nail was left outdoors where it rained twice.

3. The nail was attracted to a magnet both before and after the week.

4. The mass of the nail increased from 5.00 g to 5.08 g (after drying).

Which evidence is most directly relevant to the claim that iron reacted with oxygen?

A student claims: "Mixing solutions of silver nitrate and sodium chloride causes a chemical reaction (a precipitate forms)."

Evidence/observations:

1. A cloudy white solid appears immediately after mixing.

2. The beaker feels slightly cooler to the touch.

3. When the mixture is filtered, a white solid remains on the filter paper.

4. The original silver nitrate solution was clear and colorless.

5. The total volume after mixing is about 100 mL.

Which pieces of evidence are most directly relevant to supporting the claim that a precipitate formed due to a chemical reaction?