Question

The pressure in a 5.75 L container of 48.0 g of bromine gas at 100.0°C is ....... What is the pressure in atm?

Answer 1

Alright, so we want to use the ideal gas law to solve for Pressure.

`PV=nRT`

Pressure is unknown
Volume is 5.75 L
n is the number of mols, which we must solve for
R is the gas constant, 0.082
T is the temperature in K, which we must solve for

Solving for n: As you may recall, the formula for moles is `n=(mass)/(molar mass)`. We know that the mass is 48.0 grams, and that the Molar Mass of Br is 79.90. However, Br is diatomic (it's formula is `Br_2`), therefore we must multiply the molar mass by 2, to get 159.8.

Using this, we solve that n=0.300

Solving for T in K: We are given that the temperature is 100.0ºC. The formula for converting ºC-->K is: `ºC+273.15=K`

Therefore, the temperature is 373.2 K

Now, we can plug this all into the Ideal Gas Law to solve for Pressure in atm

`P(5.75)=(0.300)(.082)(373.2)`
`P=((0.300)(.082)(373.2))/(5.75)`
`P=1.60 atm`