Question

1. Three gases (8.00 g of methane, CH4, 18.0 g of ethane,C2H6, and an unknown amount of propane,C3H8) were added to the same 10.0- L container. At 23.0?C, the total pressure in the container is 3.60atm. Calculate the partial pressure of each gas in the container

2.A gaseous mixture of O2andN2contains 38.8{\rm \\%} nitrogen by mass. What is the partial pressure of oxygen in the mixture if the total pressure is 285mmHg?

Answer 1

1.Calculate how many moles of methane and propane you have.

Calculate how many moles in total you have using the ideal gas equation PV=nRT. The moles of propane is the total moles - (moles of methane + moles of ethane).

moles methane/total moles * 3.6 atm = partial pressure of methane

Repeat for ethane and propane.

2. want: x P O2
formula: Ptotal=P1+P2

step 1: divide % by 100
step 2: multiply value by total
step 3: plug value into eqn and solve
step 4: check ans

38.8/100= .388
.388 x 345= 134
Ptotal=P1+P2= 345 mmHg= O2 + 134 mmHg (subtract 134 from both sides)
O2= 211 mmHg

Note: to check if this is right plug all values into eqn. and Ptotal=P1+P2