Sandy heated 20 grams of liquid hydrogen peroxide until it was completely broken down into liquid water and oxygen gas. Which of these best describes the total mass of water and oxygen that was produced?
A more than 20 grams since heat was added
B 20 grams since no matter was added or removed
C less than 20 grams since oxygen gas is very light
D more than 20 grams since there are two new substances
