# Which of the following arranges the given gases in order of increasing (smallest to largest) density at STP?

SO3, Cl2, O2, C2H4

Okay so I am pretty sure you just take weight and divide by 22.4?

so like O2 would be (16.00+16.00)/(22.4) but not sure HELP!!

### 3 Answers

- electron1Lv 74 weeks agoFavorite Answer
I agree with you. At STP, the volume of one mole of gas is 22.4 liters. To calculate the density of the gas divide the mass of one mole of the gas divided by this volume.

For SO3, mass of one mole = 32 + 3 * 16 = 80 grams

Density = 80 ÷ 22.4 (3.57 g/L)

For Cl2, mass of one mole = 71 grams

Density = 71 ÷ 22.4 (3.16)

For O2, mass of one mole = 2 * 16 = 32 grams

Density = 32 ÷ 22.4 (1.43 g/L)

For CH4, mass of one mole = 12 + 4 = 16 grams

Density = 16 ÷ 22.4 (0.714 g/L)

Since we divide the mass of one mole by the same number, the ratio of densities is same as the rato of the mass of one mole.

Smallest to largest = CH4 : O2 : Cl2 : SO3

I hope this is helpful for you.

- hcbiochemLv 74 weeks ago
The density of a gas increases with the molar mass of the gas. So all you need to do is to order the gases by increasing molar mass, and that will be the order of increasing density.

C2H4 : O2 : Cl2 : SO3 you are still correct in order smallest to largest