Question

Question 5.10 34.05 mL of phosphorus vapour weighs 0.0625 g at 546 °C and 0.1 bar pressure. What is the molar mass of phosphorus?

Class XI States of Matter Page 153

Answer 1

we know, from gaseous equation
PV = nRT
where, P is pressure , V is volume , n is no of mole , R is universal gas constant and T is Temperature .

we know, mole = given weight/molar weight
n = m/M , put it in above equation.
PV = mRT/M
M = mRT/PV
= 0.0625 g × 0.083 L atm/K/mol × 819K/0.1 × 0.987 atm × 0.03405 L
= 1250.4 g/mol

hence, molar mass of Phosphorus = 1250.4 g/mol

Answer 2

Answer:

I hope this is the correct answer.