Questions: Conservation of Mass in Chemical Reactions
3 questions to test your understanding
Score: 0 / 3
Question 1 Multiple Choice
If 10 grams of reactants undergo a chemical reaction in a sealed container, what is the total mass of the products?
ALess than 10 grams
BExactly 10 grams
CMore than 10 grams
DIt depends on the reaction
The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction. In a sealed container where nothing can escape, the total mass of products must equal the total mass of reactants — exactly 10 grams.
Question 2 True / False
When a log burns in a campfire, the remaining ash weighs less than the original log. This means mass was destroyed.
TTrue
FFalse
Answer: False
Mass was not destroyed — it was converted to gases (carbon dioxide, water vapor, and others) that escaped into the atmosphere. If you could capture and weigh all the gases plus the ash, the total mass would equal the mass of the original log plus the oxygen consumed from the air.
Question 3 Short Answer
Who is credited with establishing the law of conservation of mass through careful experiments?
Think about your answer, then reveal below.
Model answer: Antoine Lavoisier.
French chemist Antoine Lavoisier conducted precise experiments in the late 1700s, carefully weighing reactants and products in sealed containers. He demonstrated that mass is conserved in chemical reactions, earning him the title 'father of modern chemistry.' His insistence on careful measurement transformed chemistry from a qualitative art into a quantitative science.