Question

Part A

Consider 4.30 L of a gas at 365 mmHg and 20. ∘C . If the container is compressed to 2.70 L and the temperature is increased to 30. ∘C, what is the new pressure, P2, inside the container? Assume no change in the amount of gas inside the cylinder.

Express your answer with the appropriate units.

Part B

A cylinder, with a piston pressing down with a constant pressure, is filled with 2.00 moles of a gas (n1), and its volume is 47.0 L (V1). If 0.800 mole of gas leak out, and the pressure and temperature remain the same, what is the final volume of the gas inside the cylinder?

Express your answer with the appropriate units.

Part C

A sample of gas in a cylinder as in the example in Part A has an initial volume of 42.0 L , and you have determined that it contains 2.00 moles of gas. The next day you notice that some of the gas has leaked out. The pressure and temperature remain the same, but the volume has changed to 10.5 L . How many moles of gas (n2) remain in the cylinder?

Express your answer with the appropriate units.

Answer 1

A)

Given:

Pi = 365 mmHg

Vi = 4.30 L

Vf = 2.70 L

Ti = 20.0 oC

= (20.0+273) K

= 293 K

Tf = 30.0 oC

= (30.0+273) K

= 303 K

use:

(Pi*Vi)/(Ti) = (Pf*Vf)/(Tf)

(365.0 mmHg*4.3 L)/(293.0 K) = (Pf*2.7 L)/(303.0 K)

Pf = 601 mmHg

= 601/760 atm

= 0.791 atm

Answer: 601 mmHg or 0.791 atm

B)

Given:

Vi = 47.0 L

ni = 2.00 mol

nf = 1.20 mol

use:

Vi/ni = Vf/nf

47.0 L / 2.00 mol = Vf / 1.20 mol

Vf = 28.2 L

Answer: 28.2 L

C)

Given:

ni = 2.00 mol

Vi = 42.0 L

Vf = 10.5 L

use:

Vi/ni = Vf/nf

42.0 L / 2.00 mol = 10.5 L / nf

nf = 0.5 mol

Answer: 0.50 mol