34.05 mL of phosphorus vapour weighs 0.0 | Class 11 Chemistry Chapter States of Matter, States of Matter NCERT Solutions

Question:

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?

Answer:

Given,

p = 0.1 bar

V = 34.05 mL = 34.05 × 10–3 L = 34.05 × 10–3 dm3

R = 0.083 bar dm3 K–1 mol–1

T = 546°C = (546 + 273) K = 819 K

From the gas equation PV = w. RT / M, we get

M = w. RT/ Pv    ……….(1)

Substituting the given values in the equation (1), we get

M = (0.0625 / 0.1 x 34.04) X 82.1 X 819 = 123.46 g/mol

Hence, the molar mass of phosphorus is 123.46 g mol–1.


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Comments

  • Priyanshu
  • 2019-09-22 19:56:14

Very helpfull


  • Prishu
  • 2019-07-20 17:14:42

But molar mass is always constant and it is 30g/mol for phosphorus


  • VINOD M BARAD
  • 2019-05-21 14:16:40

thanku


  • THULA Rajeshwar
  • 2019-02-05 20:11:44

Thanks But R=8.314 right


  • Hi
  • 2018-10-17 20:13:08

Hi


  • Anonymus
  • 2017-12-03 16:00:28

How do you take pressure P as 82.1


Comment(s) on this Question

Welcome to the NCERT Solutions for Class 11 Chemistry - Chapter . This page offers a step-by-step solution to the specific question from Excercise 1 , Question 10: 34.05 mL of phosphorus vapour weighs 0.0625 g at 546 °C and 0.1 bar pressure. What is the molar ....