Question

1. rafael notices that after the sugar investigation, the mass of the test tube is less than it was before the sugar was burned (table 1). which of his classmates’ statements provides the best explanation for this difference, based on the given data and figures?

max: \when the sugar melted, some of the oxygen in the sugar floated away.\

andre: \when the sugar changed, some of it left the tube as carbon dioxide gas.\

megan: \when a substance changes, some of its mass is destroyed.\

sara: \the sugar changed into water, which is lighter than sugar.\

Explanation:

According to the law of conservation of mass, in a chemical reaction, mass is neither created nor destroyed. When sugar burns, it undergoes a chemical reaction with oxygen to produce carbon - dioxide gas and water vapor. These gaseous products escape from the test - tube, causing the mass of the test - tube to decrease. Max's statement about oxygen floating away is incorrect as oxygen is not a major component of solid sugar in a way that it can just float away upon melting. Megan's statement violates the law of conservation of mass. Sara's statement is wrong because sugar does not simply change into water during burning. Andre's statement is correct as carbon - dioxide gas is a product of the combustion of sugar and its escape from the tube accounts for the mass loss.

Answer:

Andre: "When the sugar changed, some of it left the tube as carbon dioxide gas."