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# Chemistry-Gases, dalton's law?????

A vessel contains 2.00 mol of He, 5.50 mol of Ar, and 1.00 mol of CH4 gases. If the partial pressure of He is 1.440 atm, what is the total pressure inside the vessel?

### 5 Answers

- 1 decade agoFavorite Answer
Partial pressure = total pressure x mole fraction

mole fraction = moles of the gas/total moles of all gases

You know the partial pressure of He and you know the mole fraction (2.00 moles He out of 8.50 moles total). Solve for total pressure

1.440 = P(2/8.50)

P = (1.440)(8.50)/2

P = 6.12 atm

- 1 decade ago
Dalton's law of partial pressures simply states that the total gas pressure in a container or a system is equal the the partial pressures of each component gas. In this problem you have been given the amount of each component gas in moles, and the pressure of the Helium component. Assuming identical conditions for all of the gases in the mixture, since they are all in the same container, you can simply use ratios to solve the problem. The helium is 2/1.44 and should be equal to argon which is 5.50/X. When you solve this inequality, you get 3.96atm. The equality of 2/1.44 = 1/X gives a partial pressure to methane (CH4) of .72 When you add 1.44 + 3.96 + .72 = 6.12 atm of pressure. Hope this helps

- steve_geo1Lv 71 decade ago
2.00 mol He + 5.50 mol Ar + 1.00 mol CH4 = 8.50 mol gases. He = 2.00/8.50 x 100% = 23.5-mol%. The partial pressure of He is 1.44 atm (to three significant figures). The mol% of the rest of the gases is 76.5%. So the total pressure is 6.12atm.

What I don't understand is your evocation of Dalton's law?????

- Marcella SLv 51 decade ago
Pressure is .72 atm/mole. total number of moles of gas in vessel:

2 + 5.5 + 1 = 8.5 moles

8.5(.72) = 6.12 atm

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- colgroveLv 44 years ago
PV= nRT you will desire to discover the n moles of the entire mixture. Then, divide the partial tension (moles)of N2 through the entire moles of the aggregate. Then multiply through the entire tension.