Question #c1c9e

1 Answer
May 30, 2014

The approximate temperature is 20 °C.

To solve this problem, we can use the Ideal Gas Law

#PV = nRT#.

In the formula, #P# is the pressure, #V# is the volume, #n# is the number of moles of gas, #R# is the Universal Gas Constant, and #T# is the Kelvin temperature.

We want to solve the Ideal Gas Law for #T#.

To get #T# by itself, we must divide both sides of the equation by #nR#:

#PV = nRT#

#(PV)/(nR)# = #(nRT)/(nR)#

#(PV)/(nR) = T#.

Thus,

#T = (PV)/(nR)#

Substituting values, we get

#T = (PV)/(nR) = (0.987"atm" × 12"L")/(0.50"mol" × 0.082 06"L·atm·K⁻¹mol⁻¹")# = 290 K

Notice how the units cancel to give the temperature in kelvins.

Now we convert to the Celsius temperature:

290 K = (290 - 273.15)°C ≈ 20 °C

Note: I have calculated the answer to only 1 significant figure, because the number of moles and the volume had only 2 significant figures.

The calculated Kelvin temperature had only 2 significant figures. When we subtracted 273.15, we lost one of these significant figures. If you need more precision, you will have to recalculate.