0 . 64 g of an oxide of sulphur occupies 0 . 224 L at 2 bar and 273 o C . Identify the compound. Also find out the mass of one molecule of the gas.

Given, Volume = 0 . 224 L Moles = 0 . 64 x [Let x = molecular weight of gas] 1 mole consist 22 . 4 L at STP 0 . 64 x mole consist = 0 . 64 x × 22 . 4 = 14 . 336 x L Calculated volume is equal to the given volume. 14 . 336 x = 0 . 224 L x = 14 . 336 0 . 224 = 64 g / mol So, 64 g / mol is the molecular weight of SO 2 64 g of sulphur dioxide is equal to 6 . 023 × 10 23 molecules Mass of one molecule of gas = 64 6 . 023 × 10 23 = 10 . 62 × 10 - 23 = 1 . 062 × 10 - 22 g

A discharge tube of 2 L capacity containing hydrogen gas was evacuated till the pressure inside is 1 × 10 - 5 atm . If the tube is maintained at a temperature of 27 o C , Calculate the number of hydrogen molecules still present in the tube.

Given, V = 2 L , P = 1 × 10 - 5 atm or bar T = ( 27 + 273 ) = 300 K Number of moles = ? or n = ? R = 0 . 0821 L atm K - 1 mol - 1 PV = nRT n = PV / RT = 1 × 10 - 5 × 2 0 . 0821 × 300 = 0 . 081 × 10 - 5 mol But we know that one mole molecules are equal to 6 . 023 × 10 23 molecules. 0 . 081 × 10 - 5 moles equal to 6 . 023 × 10 23 × 0 . 081 × 10 - 5 1 = 0 . 487 × 10 18 Number of H 2 molecules = 4 . 87 × 10 17

30 mol of chlorine gas occupies a volume of 500 ml at 315 K and 4 × 10 5 Pa pressure. Calculate the compressibility factor of the gas. ( R = 0 . 083 L bar K - 1 mol - 1 ).

Given, P = 4 × 10 5 Pa ≈ 4 bar n = 30 mol T = 315 K R = 0 . 083 L bar K - 1 mol - 1 V = 500 mL = 0 . 5 L Compressibility factor, Z = PV nRT Substitute the values in the above equation. Z = 4 × 0 . 5 30 × 0 . 083 × 315 = 2 . 54 × 10 - 3

E M B I B E

ALL IN ONE ISC Chemistry CLASS 11>Chapter 5 - States of Matter : Gases and Liquids>Chapter Practice>Q 22

MEDIUM

11th ICSE

IMPORTANT

Earn 100

A $2 L$ flask contains $1.6 g$ of methane and $0.5 g$ of hydrogen at $27^{o} C$ . Calculate the partial pressure of each gas in the mixture and also calculate the total pressure.

Important Questions on States of Matter : Gases and Liquids

MEDIUM

11th ICSE

IMPORTANT

ALL IN ONE ISC Chemistry CLASS 11>Chapter 5 - States of Matter : Gases and Liquids>Chapter Practice>Q 23

$0.64 g$ of an oxide of sulphur occupies $∴ Total pressure = P_{{CH}_{4}} + P_{H_{2}} = 1.23 + 3.079 = 4.31 atm$ at $2 bar$ and $273^{o} C$ . Identify the compound. Also find out the mass of one molecule of the gas.