Do substances have to be cold to freeze?

No.

Explanation:

90% of the time when someone hears the word "freeze", they think cold.

However, at its core, to freeze, is to become solid, and there are many solid materials that aren't necessarily cold, for instance Lava is hot, and once it cools it becomes a form of rock that is not necessarily cold, however it has frozen into a solidified form.

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

answer by yourhope:

how do models compare to real-world objects?

d. most models represent a real-world object in a simpler way.

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