A model is simplified version of a more complex idea or system. It useful to help us understand something we can't actually see A) true

B) false

I feel like the answer is A) true

Explanation:

you create a model to help your audience understand your complex idea. There have been models made to represent ideas that we cannot see.

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.

since electrons are negative the answer is neagtaive