Chapter U4.4, Problem 7E

Interpretation Introduction

Interpretation: How the matter is conserved in case of burning a piece of paper needs to be explained.

Concept Introduction :

According to law of conservation of matter “matter can neither be created nor be destroyed and it changes from one form to another form.”

Answer to Problem 7E

The total mass of reactants should be equal to the total mass of products.

Explanation of Solution

Combustion is a chemical reaction in which the substance reacts with oxygen and produce carbon dioxide and water vapor along with some ashes.

Paper is made of wood which is a mixture of hydrocarbons.

On burning of paper, it turns into ash and release some smoke.

Mass of the paper = Mass of ash + mass of smoke released

The mass of released gases cannot be determined but it does not mean that conservation of mass does not take place.

Paper changed from one form to another and there is no loss of matter.

This proves the law of conservation of matter.