Chapter 10, Problem 86GQ

### Chemistry & Chemical Reactivity

10th Edition
John C. Kotz + 3 others
ISBN: 9781337399074

Chapter
Section

### Chemistry & Chemical Reactivity

10th Edition
John C. Kotz + 3 others
ISBN: 9781337399074
Textbook Problem

# If you have a sample of water in a closed container, some of the water will evaporate until the pressure of the water vapor, at 25 °C, is 23.8 mm Hg. How many molecules of water per cubic centimeter exist in the vapor phase?

Interpretation Introduction

Interpretation:

For a given sample of water in closed container the molecules of water present under given volume should be determined.

Concept Introduction:

Ideal gas Equation:

Any gas is described by using four terms namely pressure, volume, temperature and the amount of gas.  Thus combining three laws namely Boyle’s, Charles’s Law and Avogadro’s Hypothesis the following equation could be obtained.  It is referred as ideal gas equation.

nTPV = RnTPPV = nRTwhere,n = moles of gasP = pressureT = temperatureR = gas constant

Under some conditions gases don not behave like ideal gas that is they deviate from their ideal gas properties.  At lower temperature and at high pressures the gas tends to deviate and behave like real gases.

Boyle’s Law:

At given constant temperature conditions the mass of given ideal gas in inversely proportional to its volume.

Charles’s Law:

At given constant pressure conditions the volume of ideal gas is directly proportional to the absolute temperature.

Two equal volumes of gases with same temperature and pressure conditions tend to have same number of molecules with it.

Explanation

Given:

â€‚Â TÂ =Â 25Â oC=273.15+25Â =Â 298.15KVÂ =Â perÂ cubicÂ centimeterÂ =Â 1mL=1Ã—10-3LP=23.8mmHg=23.8760=0.03132atmMolecules=?

In order to find the number of molecules present first the moles of the water vapor should be determined.

The moles is determined as follows,

â€‚Â PV=â€‰â€‰nRTâ€‰â€‰â€‰nÂ =PVRTâ€‰â€‰â€‰â€‰â€‰Â =Â 0.03132Ã—1Ã—10-30.0821Ã—298.15â€‰â€‰â€‰â€‰â€‰â€‰=1.28Ã—10-6molesNoÂ ofÂ moleculesÂ =Â MolesÃ—6.023Ã—1023â€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€Šâ€ŠÈ€

### Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

#### The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started