Question

Part A) A chemical reaction occurring in a cylinder equipped with a moveable piston produces 0.621 mol of a gaseous product. If the cylinder contained 0.260 mol of gas before the reaction and had an initial volume of 2.09 L , what was its volume after the reaction? (Assume that pressure and temperature are constant and that the initial amount of gas completely reacts.) Express the volume to thee significant figures and include the appropriate units.

PartB) A syringe containing 1.49 mL of oxygen gas is cooled from 92.5 ∘C to 0.7 ∘C. What is the final volume Vf of oxygen gas? (Assume that the pressure is constant.)

PartC) A sample of gas has an initial volume of 14.4 L at a pressure of 1.07 atm. If the sample is compressed to a volume of 10.5 L , what is its pressure? Express the pressure in atmospheres to three significant figures.

Part D) A sample of nitrogen gas in a 1.61-L container exerts a pressure of 1.52 atm at 19 ∘C. What is the pressure if the volume of the container is maintained constant and the temperature is raised to 361 ∘C? Express the pressure in atmospheres to three significant figures.

Answer 1

A)

Given:

Vi = 2.09 L

ni = 0.260 mol

nf = 0.621 mol

use:

Vi/ni = Vf/nf

2.09 L / 0.260 mol = Vf / 0.621 mol

Vf = 4.99 L

Answer: 4.99 L

B)

Given:

Vi = 1.49 mL

Ti = 92.5 oC

= (92.5+273) K

= 365.5 K

Tf = 0.7 oC

= (0.7+273) K

= 273.7 K

use:

Vi/Ti = Vf/Tf

1.49 mL / 365.5 K = Vf / 273.7 K

Vf = 1.12 mL

Answer: 1.12 mL

C)

Given:

Pi = 1.07 atm

Vi = 14.4 L

Vf = 10.5 L

use:

Pi*Vi = Pf*Vf

1.07 atm * 14.4 L = Pf * 10.5 L

Pf = 1.47 atm

Answer: 1.47 atm

D)

Given:

Pi = 1.52 atm

Ti = 19.0 oC

= (19.0+273) K

= 292 K

Tf = 361.0 oC

= (361.0+273) K

= 634 K

use:

Pi/Ti = Pf/Tf

1.52 atm / 292.0 K = Pf / 634.0 K

Pf = 3.30 atm

Answer: 3.30 atm