Gases

Question 1

Molarity

Answer 1

Mol solute/ L solution

Question 2

Molality

Answer 2

Mole solute / kg solvent

Question 3

Mole fraction

Answer 3

Moles part /moles total

Question 4

Mass percent

Answer 4

Mass part / total mass (100)

Question 5

A gas w/ a pressure of 652 torr at 25°C occupies a volume of 455mL. What is the volume of this gas at STP?

Answer 5

P1V1/T1 = P2V2/T2

Question 6

How many molecules of ch4 are contained in 1 mL at stp?

Answer 6

pv=nrt ( then convert to molecules )

Question 7

.425 mol oxygen and .871 mol of SO3 are stored in a 2L container at 300 K. What is the pressure of each gas and the total pressure of the container?

Answer 7

Pv=nrt to find pressures

Add those pressures together

Question 8

H2 escapes a container at a rate of 2.45 g/min. What is the rate of escape for cl2?

Answer 8

2.45/r2

R2= square root of molar mass of cl2/ molar mass H2

Question 9

A mixture of .7 mol oxygen and .3 mol nitrogen has a total pressure of 2 ATM at 298 k. What is the partial pressure of each gas?

Answer 9

O2= (.7/1)2 N2=(.3/1)2

Question 10

What is the molar mass of a gas with a density of 3.42 g/L at 755 torrs and 293 k?

Answer 10

Pmm=rtd

Question 11

Determine the speed of a sf6 molecule at 298°K

Answer 11

Square root of 3(8.314)(298)/ mass

Then divide that by 1000