Chapter 14.2, Problem 7RQ

Interpretation Introduction

Interpretation: The reason for potatoes to take different time in boiling in two different countries given needs to be explained.

Concept introduction: Boiling point can be defined as a temperature where vapor pressure of the liquid becomes equal to the normal atmospheric pressure (1 atm) and hence the liquid gets converted into gaseous state.

Boiling point of a substance depends on the atmospheric pressure of its surroundings.

Answer to Problem 7RQ

Atmospheric pressure at L, C is less than M, W hence water boils at low temperature at L, C compared to M, W.

Explanation of Solution

With increase in altitude, atmospheric pressure decreases. Hence, vapor pressure of the liquid readily matches the vapor pressure of surrounding (atmospheric pressure) which in turn reduces the boiling point.

L, C are elevated at 10,000 ft from sea-level whereas M, W are elevated at 900 ft and hence water boils at low temperature ( $90C$ ) in L, C and at ( $99C$ ) in M, W. Water at $90C$ contains lesser energy than water at $99C$ and hence it takes longer to boil the potato at L and C.

Conclusion

Atmospheric pressure at L, C is less than M, W hence water boils at low temperature at L and Colorado compared to M and W.