Question

6. Molar Density of Gases

A. what is the density of Ne at 100 Celsius and 2.5 atm?

B. what is the density of carbon dioxide at 25 Celsius and 1.0 atm?

C. What is the molar mass of a gas with a density of 3.93 g/L at 250 K and 1 atm?

7. Application of Gas Laws:

A. Calculate the molar mass of a gas if 0.152 g of the gas occupies 0.500 L at STP

B. On a spring morning (21 Celsius) you fill your tires to a pressure of 2.30 atm. As you ride along, the tire heats up to 35 Celsius from the friction on the road. What is the pressure in your tires now?

C. How much will the volume of an ideal gas change when its temperature is decreased from 675 K to 225 K at 1 atm pressure?

D. What is the effect on the volume of an ideal gas when both the pressure and temperature are doubled?

E. What is the effect on the volume of an ideal gas when the pressure is changed from 750 torr to 0.655 atm, and the temperature is changed from 25 Celsius to 278 K?

Answer 1

A. PM = dRT d = PM/RT = 2.5 times 20/0.0821 times 373 = 1.63g/L PM = dRT d = PM/RT = 1 times 44/0.0821 times 298 = 108 g/2 PM = dRT M = dRT/P = 3.93 times 0.0821 times 250/1 = 88.66 g/mol pv = w/m times r times T M = WRT/PV = 0.15 times 0.0821 times 273/1 times 0.5 M = 6.81 91mvl P_1/T - 1 = P_2/T_2 2.3/294 = p_2/308 implies p_2 = 2.3 times 308/27+ = 2.4 atm