Final answer:
No, the experiment does not support the student's claim because it was not performed in a closed system. The apparent loss of mass is due to the unmeasured gaseous products escaping into the atmosphere, not to a violation of the law of conservation of mass.
Step-by-step explanation:
The student's observation that the mass of the liquid after the chemical reaction is less than the mass of the alcohol before the reaction may seem to suggest that mass is not conserved. However, this is not valid evidence to support the student's claim.
The crucial detail here is that the student's experiment is not conducted in a closed system. When alcohol burns in an open dish, it reacts with oxygen from the air to create water and carbon dioxide gas. The gaseous products may escape into the atmosphere, which results in a decrease in the observed mass after combustion. This discrepancy does not violate the law of conservation of mass, which states that mass is conserved in a closed system, where no matter can enter or exit.
24(a) The mass of the baked loaf is less than the one pound of original dough because water vapor and other gases are released into the atmosphere during the baking process. (b) The mass of magnesium oxide is greater than the original magnesium because it combines with oxygen from the air. (c) The mass of sealed flask and contents remains the same after heating, as Antoine Lavoisier demonstrated, even though a chemical change occurred.
25. Yeast converts glucose to ethanol and carbon dioxide through fermentation. This equation also obeys the law of conservation of mass.