Question

How do you calculate the volume of 25.0 g of carbon monoxide at STP?

Answer 1

The volume is 20.3 L.

Explanation:

We can convert the mass of carbon monoxide to moles and then use the Ideal Gas Law to calculate the volume at STP.

Moles of `"CO"`

`"Moles of CO" = 25.0 color(red)(cancel(color(black)("g CO"))) × ("1 mol CO")/(28.01 color(red)(cancel(color(black)("g CO")))) = "0.8925 mol CO"`

Volume at STP

The Ideal Gas Law is:

`color(blue)(|bar(ul(PV = nRT)|)`,

where

• `P` is the pressure
• `V` is the volume
• `n` is the number of moles
• `R` is the gas constant
• `T` is the temperature

We can rearrange the Ideal Gas Law to get

`V = (nRT)/P`

STP is 1 bar and 0 °C.

`n = "0.8925 mol"`
`R = "0.083 14 bar·L·K"^"-1""mol"^"-1"`
`T = "273.15 K"`
`P = "1 bar"`

`V = (nRT)/P = (0.8925 color(red)(cancel(color(black)("mol"))) × "0.083 14" color(red)(cancel(color(black)("bar")))·"L"· color(red)(cancel(color(black)("K"^"-1""mol"^"-1"))) × 273.15 color(red)(cancel(color(black)("K"))))/(1 color(red)(cancel(color(black)("bar")))) = "20.3 L"`