Jay had two clear liquids in bottles. the mass of one liquid was 10.2 grams and the other was 7.6 grams. When he mixed them, a yellow solid formed and settled to the bottom of the bottle. He predicted that the liquid plus the solid would have more mass, so he put the bottle on a scale. The mass was 17.8 grams. Why did the mass not change? A chemical reaction occurred, which means the atoms rearranged to form new substances.
A chemical reaction occurred, which means even though the old atoms turned into new atoms, they had the same mass.
Jay must have made an error in measuring the mass before or after he mixed the liquids.
One of his classmates probably did something to affect his experiment.