Chapter 17, Problem 1DQ

(a)

Interpretation Introduction

Interpretation: The reason for transfer of water from one beaker to another need to be explained.

Concept Introduction : The pressure exerted by vapor in the state of equilibrium in a system which is closed is vapor pressure. Intermolecular forces, Surface area and temperature are some factors that influence in vapor pressure. A molecule's vapor pressure varies with temperature.

Answer to Problem 1DQ

The transfer of water from one beaker to another occurs to attain equilibrium.

Explanation of Solution

If the vapour pressure of solution is less than the vapor pressure of the pure solvent, the vapor pressure required to attain equilibrium in pure solvent is more than vapor pressure needed to attain equilibrium with acid solution which is aqueous. Therefore, the emission of vapor by pure solvent lowers the vapour pressure towards equilibrium.

(b)

Interpretation Introduction

Interpretation: The importance of terms ‘vapor pressure’ and ‘equilibrium’ in the given phenomenon needs to be explained.

Concept Introduction : The pressure exerted by vapor in the state of equilibrium in a system which is closed is vapour pressure. Chemical equilibrium is defined as the state where both products and reactants present in quantities that do not change with time.

Answer to Problem 1DQ

Particular pressure in which gaseous form of a substance exists in thermodynamic equilibrium with its solid or liquid form is the vapor pressure.

Explanation of Solution

The pressure exerted by vapor in the state of equilibrium in a system which is closed is vapour pressure. There is a tendency of all solids and liquids that they can change their state to gaseous state by evaporation and the gases possess a tendency to came back to their original state at particular temperature.

Particular pressure in which gaseous form of a substance exists in thermodynamic equilibrium with its solid or liquid form is the vapor pressure.

(c)

Interpretation Introduction

Interpretation: Whether all the water transferred to the second beaker or not needs to be determined.

Concept Introduction : Chemical equilibrium is defined as the state where both products and reactants present in quantities that do not change with time.

Answer to Problem 1DQ

Yes, the transfer of all water molecules happens.

Explanation of Solution

Yes, the transfer of all water molecules happened. When transfer of all water happens to the solution then only system can reach equilibrium vapor pressure.

(d)

Interpretation Introduction

Interpretation: Whether the water in the beaker containing the solute evaporates or not needs to be explained. If yes whether the rate of evaporation increasing, decreasing, or staying constant needs to be determined.

Concept Introduction: Evaporation occurs on liquid’s surface. It refers to the change of liquid state to gaseous. An evaporation rate is the rate at which a substance vaporizes.

Explanation of Solution

The decrease in count of molecules of solvent is due to the non-volatile solute dissolved in the solution. They lower the tendency of escape of solvent molecules from the solution. This is the reason of decrease of evaporation.