Question

If a mixture of gases contained 78% nitrogen at a pressure of and 22% carbon dioxide at , what is the total pressure of the system? 1,329 atm 17.5 cm hg 639 torr 1.75 atm none of these

Answer 1

The pressures given are the partical pressures of the two gases.

The law of Dalton or of the partial pressures states that the total pressure of a mixture of gases is equal to the sum of the pressures of all the gases.

So, in this case:

Total pressure = pressure of nitrogen + pressure of carbon dioxyde.

Of course both terms must be in the same units.

i have found that the pressures for this problem are:

Pressure of nitrogen = 984 torr

Pressure of carbon dioxyde = 345 torr

Total pressure = 984 torr + 345 torr = 1329 torr.

Now convert to atm: 1 atm = 760 torr

=> 1329 torr * 1 atm / 760 torr = 1.74868 atm ≈ 1.75 atm

Answer: 1.75 atm