Chapter 2, Problem 3STP

Interpretation Introduction

Interpretation: An example of a chemical change needs to be explained.

Concept Introduction: The nature of any substance is explained by their chemical properties and physical properties. A chemical property describes how a substance reacts with other substances. In a chemical change, a new substance is formed and absorption of energy or loss of energy occurs; it is an irreversible change. For example, rusting, dissolving, etc.

Answer to Problem 3STP

Correct answer: Option B.

Explanation of Solution

Reason for correct option: A nail is capable of combining with oxygen to form iron oxide, called rust. In other words, when iron comes in the contact with air and moisture, oxygen and iron combine to form a product iron oxide. In this process a new substance is formed and also, this is irreversible process. So, option B is a chemical change.

Conclusion

Reasons for incorrect options:

Option A: This is a physical change. So, this is an incorrect option.

Option C: This is a physical change. So, this is an incorrect option.

Option D: This is a physical change. So, this is an incorrect option.