A sample of gas has a mass of 38.7 mg. Its volume is 228 mL at a temperature of 53 ∘C and a pressure of 885 torr. Find the molar mass of the gas.

Molar mass of the gas = 3.91 g/mol

Explanation:

Let's apply the Ideal Gases Law to solve this:

We convert the pressure from Torr to atm → 885 Torr . 1atm / 760 Torr = 1.16 atm

We convert T°C to T°K → 53°C + 273 = 326 K

We convert the volume from mL to L → 228 mL . 1L/1000mL = 0.228L

Now we can replace = 1.16 atm . 0228L = n . 0.082 .326K

(1.16 atm . 0.228L) / (0.082 / 326K) = n → 9.89×10⁻³ moles.

Let's convert the mass from mg to g → 38.7 mg . 1g / 1000 mg = 0.0387 g

Molar mass → g/mol → 0.0387 g / 9.89×10⁻³ mol = 3.91 g/mol

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)