Question

1)Choose all of the statements below that would change the volume of gas depicted in Cylinder A to that of Cylinder B.

a□ Increase the pressure by a factor of 6 while holding the Kelvin temperature and the moles of gas constant.

b□Reduce the pressure by a factor of 6 while holding the temperature and the moles of gas constant.
c□Increase the Kelvin temperature by a factor of 6 while holding the pressure and the moles of gas constant.
d□Simultaneously double the pressure and decrease the Kelvin temperature by a factor of 3 while holding the number of moles constant.
e□Simultaneously halve both the pressure and the Kelvin temperature while holding the number of moles of gas constant.
Select all of the above that apply

2)How many Ne atoms are present in a 2.80 L sample of Ne at STP? (Enter your answer using scientific notation. For scientific notation, 6.02 x 102323 is written as 6.02E23.)

3)What is the temperature, in ºC, of 0.938 moles of Cl2 gas with a pressure of 3.24 atm and volume of 9.31 L?

4)What is the volume, in L, of 0.690 moles of O2 gas having a temperature of 67.9 ºC and pressure of 5.86 atm?

5)A gaseous mixture composed of 16.0 g of O2 , 21.0 g of N2, and 16.0 g of He at 20.0°C is confined in a 25.0 L container.
What is the partial pressure of N2 in this mixture?

6)A gaseous mixture composed of 16.0 g of 2, 21.0 g of N2, and 16.0 g of He at 20.0°C is confined in a 25.0 L container.
What is the partial pressure of He in this mixture?

7)Assuming ideal gas behavior, what is the pressure in atm exerted by 1.57 mol Cl2(g) confined to a volume of 1.50 L at 273K?

Answer 1

1) We use gas laws to answer this question.

There are following statements that changes the volume.

a. First statement holds the Boyl’s law. P is inversely proportional to the volume

so volume would reduce in this case.

b. This statements also holds Boyl’s law where volume increase by factor 6 when pressure is reduced by 6 factor.

c. volume and temperatures are directly proportional to each other. So there is change in volume.

d. In this statement, if pressure is doubled the volume would be halved. And when temperature is raised by factor 3 , volume would become 3 times of halved which is not equal to initial volume. So there is also change in volume.

Q. 2

Number of Ne atoms = mol x Avogadro number

Calculate the moles

At STP

1 mol Ne = 22.4 L of Ne

Calculate the number of moles

n Ne = 2.80 L x 1 mol / 22.4 L = 0.125 mol Ne

Number of Ne atoms = 0.125 mol Ne x 6.022 E23 Ne atoms.

Number of atoms of Ne = 7.52 E 22

3)

We use ideal gas law

pV=nRT

T = pV/n R

Here p is the pressure in atm, V is the volume in L , n is the number of moles and R is the gas constant ( 0.08206 L atm / K mol)

T = ( 3.24 x 9.31 )/(0.938 x 0.08206)

=391.886 K

T in degree C= 391.886 K – 273.15 = 118.7 degC

4)

Use ideal gas equation to find the volume

V = nRT / P = 0.690 x 0.08206 x (67.9+273.15)/5.86

= 3.30 L

Volume in L = 3.30 L