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Question

Question
What do these two changes have in common? Select all that apply.

rust forming on a metal gate
snails growing shells
(1 point)
Responses

Both are chemical changes
Both are chemical changes

Both conserve mass
Both conserve mass

Both are only physical changes
Both are only physical changes

Both are changes in state
Both are changes in state
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Answer 1

The two changes you mentioned—rust forming on a metal gate and snails growing shells—can be analyzed as follows:

1. Rust forming on a metal gate: This is a chemical change because it involves a reaction between the iron in the metal and oxygen (from the air) in the presence of moisture, leading to the formation of iron oxide (rust).

2. Snails growing shells: This involves biological processes where the snail secretes calcium carbonate to form its shell. This can be viewed as a physical change since it is an addition to the snail's structure, but it does involve chemical processes as well in the formation of calcium carbonate.

Based on this analysis:

• They do not both qualify as chemical changes as snails growing shells can also involve physical processes.
• They both conserve mass since, according to the law of conservation of mass, the mass of substances before and after a chemical or physical change does not change.
• They are not both purely physical changes; one is clearly a chemical change.
• They do not both qualify as changes in state since that term typically refers to changes between solid, liquid, and gas states rather than biological growth processes or rust formation.

Therefore, based on the assessment, the correct response is:

Both conserve mass.