Question

A flask contains 500 cm3 of SO2 at STP. The flask contains;
(a) 40 g
(b) 100 g
(c) 50 g
(d) 1.427g​

Answer 1

Given info : A flask contains 500 cm³ of SO₂ gas at STP.

To find : the mass of SO₂ gas in the flask is ...

solution : at standard temperature and pressure,

temperature, T = 273K

pressure , P = 1 atm

volume of gas, V = 500 cm³ = 0.5L

universal gas constant , R = 0.082 Latm/mol/K

now using formula, PV = nRT

⇒ 1 atm × 0.5L = n × 0.082 atm L/mol/K × 273K

⇒ 0.5/(0.082 × 273) = n

⇒ n = 0.0223

⇒ no of moles = n =  0.0223

⇒ mass of SO₂ gas/molar mass of SO₂ = 0.0223

⇒ mass of SO₂ gas = 0.0223 mol  × 64 g/mol  [∵ molar mass of SO₂ = 64 g/mol ]

⇒ mass of SO₂ gas = 1.427 g

therefore the mass of SO₂ gas in the flask is 1.427 g.

Answer 2

Answer:

1.427

Explanation:

At STP we know:-

22.414dm3 = 1 mole

so

0.5dm3 = x moles. :-500cm3 = 0.5dm3

cross multiply

x(22.414) =0.5

x=0.5/22.414

x=0.0223 moles

To find mass:-

mass=moles× molar mass

mass=0.0223×64

mass= 1.427g