Answer:
the shape of a piece of matter can change
The total number of atoms make up the products :
D) 1 carbon, 4 hydrogen, and 4 oxygen
<h3>Further explanation
</h3>
Complete combustion of Hydrocarbons with Oxygen will produce CO₂ and H₂O compounds.
If O₂ is insufficient there will be incomplete combustion produced by CO and H and O
Hydrocarbon combustion reactions (especially alkanes)
For combustion of methane (CH₄) and two molecules of oxygen (O₂).

The number of atoms make up the products
CO₂ : 1 carbon, 2 oxygen
2H₂O : 4 hydrogen , 2 oxygen
C, a compound because it means it was made up of more than one element but, still able to be separated from the other compound(s)
Explanation:
2H2 + O2 = 2H2O
2mol. 1mol. 2mol
2mol reacts with 1mol
13mol reacts with x
x=<u>13mol</u><u> </u><u>×</u><u> </u><u>1mol</u>
<u> </u><u> </u><u> </u><u> </u><u> </u><u> </u><u> </u><u> </u><u> </u><u>2mol</u>
x= <u>13mol</u>
<u> </u><u> </u><u> </u><u> </u><u> </u><u> </u>2mol
x= 6.5mol of oxygen