Concise Physical Chemistry

c01 JWBS043-Rogers September 13, 2010 11:20 Printer Name: Yet to Come

16 IDEAL GAS LAWS

Problem 1.8

We have two expressions for the molar volume of an ideal gas: (1)Vm= 22 .414 L

at 0◦C and 1 atm and (2)Vm= 24 .790 dm^3 at 25◦C and 1 bar. (The atm and bar

are taken to have an indefinite number of significant digits.) Use this information to

obtain absolute zero(T=0K)on the Centigrade scale.

Problem 1.9

If a gas occupies 47.6 dm^3 at NSTP=298.15 K, what is its volume at 1.00 bar and

500 K? The acronym fornew standard temperature and pressureNSTP replaces the

old STP for standard temperature and pressure.

Problem 1.10

(a) Suppose that 18.44 g of N 2 occupies a container atnew standard temperature

and pressureNSTP and 24.35 g of a sample of a different gas is introduced into

the container, keeping the temperature constant. If the pressure after addition

is 3.20 bar, what is the average molar massMavof the mixture?

(b) What is the molar mass of the introduced gas?

Problem 1.11

A pure gas takes twice as long as helium to effuse through a porous membrane. What

is its molar mass?

Problem 1.12

Compute the root mean square speed of H 2 molecules at 1000 K.

Problem 1.13

What is the translational energy of 1 mol of an ideal gas atT=298.15 K?

Computer Exercise 1.14

Using a standard plotting package, plot a graph ofpV=kwherek=1, takingpas

the vertical axis andVas the horizontal axis. Play with your plotting package so as to

produce many different plots, thereby learning the idiosyncrasies of your particular

package.

Problem 1.15

What is the expectation value of the molecular speed among an ensemble of nitrogen

molecules at 298 K?