Question

What is the volume of a container that holds 25.0 g of carbon gas at STP?

Answer 1

The container has a volume of `46.6 L`.

Explanation:

Since there are only one set of conditions and we are at STP, we must use the ideal gas law equation

• P represents pressure (may have units of atm, depending on the units of the universal gas constnat)
• V represents volume (must have units of liters)
• n represents the number of moles
• R is the proportionality constant (has units of `(Lxxatm)/ (molxxK)`)
• T represents the temperature, which must be in Kelvins.

Next, list your known and unknown variables. Our only unknown is the volume of `C(g)`. Our known variables are P,n,R, and T.

At STP, the temperature is 273K and the pressure is 1 atm. The proportionality constant, R, is equal to 0.0821 `(Lxxatm)/ (molxxK)`

The only issue is the mass of `C(g)`, we need to convert it into moles of `C(g)` in order to use the ideal gas law.

`25.0cancel"g" xx (1molC)/(12.01cancel"g")` = 2.08 mol `C`

Now all we have to do is rearrange the equation and solve for V like so:
`V = (nxxRxxT)/P`
`V = (2.08molxx0.0821(Lxxatm)/(molxxK)xx(273K))/(1atm)`
`V = 46.6 L`