Calculate the molecular mass of the following:
(i) H2O
(ii) CO2
(iii) CH4
Molecules are made up of atoms & are quite small, therefore the actual mass of a molecule cannot be detrmined.It is expressed as the relative mass.C-12 isotope is used to express the relative molecular masses of substances.Thus molecular mass of a substance may be defined as: the average relative mass of its molecule as compared to the mass of carbon atom taken as 12 amu.
(i) H2O:
The molecular mass of water, H2O
= (2 × Atomic mass of hydrogen) + (1 × Atomic mass of oxygen)
= [2(1.0084) + 1(16.00 u)]
= 2.016 u + 16.00 u
= 18.016
= 18.02 u
(ii) CO2:
The molecular mass of carbon dioxide, CO2
= (1 × Atomic mass of carbon) + (2 × Atomic mass of oxygen)
= [1(12.011 u) + 2 (16.00 u)]
= 12.011 u + 32.00 u
= 44.01 u
(iii) CH4:
The molecular mass of methane, CH4
= (1 × Atomic mass of carbon) + (4 × Atomic mass of hydrogen)
= [1(12.011 u) + 4 (1.008 u)]
= 12.011 u + 4.032 u
= 16.043 u
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Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter . This page offers a step-by-step solution to the specific question from Excercise 2 , Question 13: The partial pressure of ethane over a solution containing 6.56 x 10-3 g of ethane is 1 bar. If the s....
Comments
Hey frnds this ans is correct but this is not the correct way to solve. To solve this make two equation taking no. Of moles of other component in solution as n and Henry's constant as k and partial pressure of ethane in second solution as x .While solving both equations Henry's constant and no. Of moles of other component get cancelled and u get x which is required ans.
Will you explain it in a more elaborate way?
p pressure is directly proportional to mole fraction of gas then how it becomes mass??? can anybody explain???
Partial pressure is directly proportional to the mass of the gas
P=Kh*x....where x is mole fraction then how we can replace it by mass?.... ðð
Isn't it kh*m=p. They have given it in the opposite way
I could not undrstnd that Henry\'s law states that partial pressure in vapour phase is directly proportinal to mole fraction ,then how Can it be apply directly to the given mass by replacing the mole fraction..? That is done here
Can we solve it with pie = CRT?