Question

30. What is the mass in grams of
(i) 2.24 millilitres of propane at S.T.P.?
(ii) 448 millilitres of Nitric oxide at S.T.P.?​

Answer 1

Answer:

1. CO2  has a molecular weight of 44 g/mol

1 kg  CO2  = 1000 g × (1 mol/44 g) = 22.7 mol  CO2

V=nRT/P Ideal gas law - Wikipedia

V=(22.7)(0.0821)(273.15)/1 = 509.6 L  CO2  at STP

What is the mass of 2.24 litres of  CO2  gas at STP?

(2.24/509.6)kg = 4.4g

Feel free to check the calculation.

2. You need the equation: PV=nRT

P=1atm

T=273K

V=11.2L

R=0.0821

n=?

rearrange the equation in terms of n:

PV=nRT - divide both sides by RT

n=PV/RT

now put in the info:

1x 11.2/ 273x0.0821

11.2/22.4133

=0.0446 moles of O2

now find the mass by:

0.0446 moles x atomic mass of O2

=0.0446 x 15.99(2)= 1.426g (3 sig fig)

you have 1.426g of O2

Explanation:

hope helps u