Why might a scientist repeat an experiment if he/she did not make a mistake in the first one? an experiment should be repeated to a) increase income for increased work. b) prove how interesting the study was. c) ensure the results are accurate. eliminate d) eliminate steps and save time.

The answer is C. To ensure the results are accurate.

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.