# Physics Homework Help PLZ !!!?

10 g of dry ice (solid CO2) is placed in a 10,000 cm3 container, then all the air is quickly pumped out and the container sealed. The container is warmed to 0∘ C, a temperature at which CO2 is a gas.

What is the gas pressure? Give your answer in atm.

Part B

The gas then undergoes an isothermal compression until the pressure is 3.0 atm , immediately followed by an isobaric compression until the volume is 1000 cm3 . What is the final temperature of the gas?

### 2 Answers

- az_lenderLv 74 weeks agoBest answer
The 10g is 10/44 mol = 0.22727 moles.

(a) p = nRT/V

= 0.22727mol *0.08206 L*atm/(molK) * 273.15K /

10L

= 0.5094 atm.

(b) At the end of the isothermal compression, the volume must be

(10L)*(0.5094/3.0) = 0.1698 L.

Therefore, the "isobaric compression" is actually an expansion (not a compression), and the final temperature is (273.15K)*(1/0.1698) = 1609K

= 1336C.

- 4 weeks ago
P * V = n * R * T

V = 10000 cm^3 = 10 Liters

T = 0 Celsius = 273.15 Kelvin

1 mole of CO2 has a mass of 44 grams

n = 10/44 moles = 5/22 moles

P * 10 Liters = (5/22) moles * R * 273.15 Kelvin

P = 5 * 273.15 * R / (22 * 10) [moles * Kelvin / Liters]

P = 273.15 * R / 44 [moles * Kelvin / Liters]

We need an appropriate value for R

R = 8.31446261815324 * 10^(-2) Liters * bar / (moles * Kelvin)

P = 273.15 * 8.31446261815324 * 10^(-2) / 44 bar

P = 0.51615806003376306954545454545455.... bar

P = 0.5162 bar

1 atm = 1013.25 mbar

P = 516.2 mbar

P = 516.2/1013.25 atm

P = 0.50940839875032131215934324742615

0.509 atm