A3.689 g object is added to 7.29 ml of water causing the water level to rise to 8.54 ml. what is the density of the object?

2.95 g/mL

explanation: first you find the difference between the previous and current water level:

8.54-7.29=1.25

then you place 3.689g over 1.25mL then divide:

you get 2.9512

due to significant #'s the answer is rounded and turned into:

2.95 g/mL

hoped this helped and that it's actually right-_-

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.