What is the Weight Percentage of Nitrogen in Air?

Click For Summary
SUMMARY

The weight percentage of Nitrogen in air is approximately 76%, derived from its volumetric composition of 78% Nitrogen, 21% Oxygen, and 1% Argon. The atomic weights used in the calculation are 14 for Nitrogen, 16 for Oxygen, and 40 for Argon. The calculation involves determining the total weight of the gases and finding the proportion of Nitrogen's weight relative to the total. The final result can vary slightly based on significant figures, but for practical purposes, it is accepted as 76%.

PREREQUISITES
  • Understanding of basic chemistry concepts, including atomic weights
  • Familiarity with gas composition and molar fractions
  • Basic arithmetic operations for weighted averages
  • Knowledge of significant figures in scientific calculations
NEXT STEPS
  • Review the calculation of weight percentages in gas mixtures
  • Study the concept of molar fractions in chemistry
  • Learn about the ideal gas law and its applications
  • Explore the significance of significant figures in scientific measurements
USEFUL FOR

Students studying chemistry, educators teaching gas laws, and anyone interested in understanding the composition of air and related calculations.

atim
Messages
2
Reaction score
0

Homework Statement


Air consists of approximately 78% Nitrogen in volume, 21% Oxygen and 1% Argon. The atomic weight of Nitrogen is approximately 14, that of Oxygen 16, and that of Argon 40.

Nitrogen occupies air in weight by
(1) (a) 76% (b) 77% (c)78% (d)79%

Homework Equations

The Attempt at a Solution


I don't know how to calculate, so I just tried

78*28 + 21*32 + 40 = 2896

78*28/2896 = 0.754 = 75.4%

what is the correct method?
 
Physics news on Phys.org
That is. The answer comes out very close to 75.5%, so whether you round it to 75 or 76% depends on things like the number of significant figures you took, etc. For the purpose of this question the answer is 76% (Someone has asked this question here before.)
 
  • Like
Likes   Reactions: atim
% in Vol only for gases, is a way of give the molar fraction expreseed in %.

You work is correct.
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
14K
  • · Replies 8 ·
Replies
8
Views
8K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
Replies
1
Views
10K
Replies
1
Views
2K
  • · Replies 9 ·
Replies
9
Views
12K
Replies
14
Views
2K