Chapter 11, Problem 67A

(a)

Interpretation Introduction

Interpretation:

The liquid needs to be determined when a glass of cold liquid is taken outside on a warm, humid day, and drops of liquid are found soon on outside of the glass.

Concept Introduction:

A process where water vapor becomes liquid is called as condensation process.

Answer to Problem 67A

The liquid is water.

Explanation of Solution

When a glass of cold liquid is taken outside on a warm, humid day, and drops of liquid are found soon on outside of the glass, then resulting liquid is a condensate which is formed due to condensation process.

Hence the liquid is water.

(b)

Interpretation Introduction

Interpretation:

It needs to be determined that where the liquid comes from when a glass of cold liquid is taken outside on a warm, humid day, and drops of liquid are found soon on outside of the glass.

Concept Introduction:

A process where water vapor becomes liquid is called as condensation process.

Answer to Problem 67A

The liquid comes from by the process of transition of gaseous state to liquid state.

Explanation of Solution

The necessary liquid is obtained by the process of transition of gas into liquid by removing heat to critical temperature.

Hence the liquid comes from transition of water vapor into water which is gaseous into liquid.

(c)

Interpretation Introduction

Interpretation:

It needs to be determined whether a chemical or physical change occurs.

Concept Introduction:

When the composition remains same irrespective of its molecules being rearranged then this process is called as physical change and when the molecular composition is changed entirely then chemical change occurs.

Answer to Problem 67A

The change occurred is physical.

Explanation of Solution

As the chemical properties of the liquid does not change in the transition from gaseous state to liquid state so this is a physical change.

Hence the change occurred is physical.