# Class 11 Chemistry States of Matter: NCERT Solutions for Question 15

This page focuses on the detailed States of Matter question answers for Class 11 Chemistry States of Matter, addressing the question: 'Calculate the total pressure in a mixture of 8 g of dioxygen and 4 g of dihydrogen confined in a vessel of 1 dm3 at 27°C. R = 0.083 bar dm3 K–1 mol–1.'. The solution provides a thorough breakdown of the question, highlighting key concepts and approaches to arrive at the correct answer. This easy-to-understand explanation will help students develop better problem-solving skills, reinforcing their understanding of the chapter and aiding in exam preparation.
Question 15

## Calculate the total pressure in a mixture of 8 g of dioxygen and 4 g of dihydrogen confined in a vessel of 1 dm3 at 27°C. R = 0.083 bar dm3 K–1 mol–1.

Given,

Mass of oxygen  = 8 g, molar mass of oxygen = 32 g/mol

Mass of hydrogen = 4 g, molar mass of hydrogen = 2 g/mol

Therefore amount of oxygen = 8/ 32 = 0.25 mol

And amount of hydrogen = 4/2 = 2 mol

From the gas equation PV = n RT, we get,

P X 1  = (0.25 + 2)  X 0.083 X 300 = 56.02 bar

Hence, the total pressure of the mixture is 56.02 bar.