Chemistry: An Atoms-Focused Approach
Chemistry: An Atoms-Focused Approach
14th Edition
ISBN: 9780393912340
Author: Thomas R. Gilbert, Rein V. Kirss, Natalie Foster
Publisher: W. W. Norton & Company
Question
Book Icon
Chapter 7, Problem 7.48QA
Interpretation Introduction

To calculate:

The percent composition of the following compounds

a) Sodium sulfate

b) Dinitrogen tetroxide

c) Strontium nitrate

d) Aluminum sulfide

Expert Solution & Answer
Check Mark

Answer to Problem 7.48QA

Solution:

Percent composition of each element in a given compound is:

a) Sodium sulfate contains 32.37% Na, 22.57% S and 45.05% O

b) Dinitrogen tetroxide contains 30.45% N and 69.55% O

c) Strontium nitrate contains 13.24% N, 30.24% O and 41.40% Sr

d) Aluminum sulfide contains 35.94% Al and 64.06% S

Explanation of Solution

1) Concept:

We have to find the percent composition compound of the given compounds. The chemical formula of each of the given compounds is Na2SO4, N2O4, SrNO32 and Al2S3 respectively. We first find the molar mass of each compound, and then, we find the percent composition for each element in the chemical formula by the percent composition formula.

% composition=mass of an elementtotal mass ×100

The chemical formula tells us the ratio of moles of each elements in the formula. For example: one mole of N2O4 contains two moles of N and four moles of  O.

A mole is the SI unit of amount chemical substance. When writing units, it is written as “mol”.

2) Formula:

% composition=mass of an elementtotal mass ×100

3) Given:

Chemical names for four compounds are given as:

a) Sodium sulfate

b) Dinitrogen tetroxide

c) Strontium nitrate

d) Aluminum sulfide

4) Calculations:

Calculating mass of each of the given compounds as follows:

a) Calculating mass of Na, S and O  in one mole of Na2SO4 and the molar mass of  Na2SO4:

2 mol Na ×22.99gmol=45.98 g Na

1 mol S ×32.065gmol=32.065 g S

4 mol O ×16.0gmol=64.0 g O

Molar mass of Na2SO4= 45.98+32.065+64.00=142.045 g/mol

Calculating percent composition of Na, S and O as:

% Na=45.98 g Na142.045 g ×100=32.37 % Na

% S=32.065 g S142.045 g ×100=22.57 % S

% O=64.0 g O142.045 g ×100=45.06 % O

b) Calculating mass of N and O  in one mole of N2O4  and the molar mass of  N2O4 :

2 mol N ×14.007gmol=28.014 g N

4 mol O ×16.0gmol=64.0 g O

Molar mass of N2O4  = 28.014+64.00=92.014 g/mol

Calculating percent composition of N and O as:

% N=28.014 g N92.014 g ×100=30.45 % N

% O=64.0 g O92.014 g ×100=69.55 % O

c) Calculating mass of Sr, N and O  in one mole of SrNO32  and the molar mass of  SrNO32 :

2 mol N ×14.007gmol=28.014 g N

6 mol O ×16.0gmol=96.0 g O

1 mol Sr ×87.62gmol=87.62 g Sr

Molar mass of N2O4  = 28.014+96.0+87.62=211.654 g/mol

Calculating percent composition of Sr, N and O as:

% N=28.014 g N211.654 g ×100=13.24 % N

% O=96.0  g O211.654g ×100=45.36 % O

% Sr=87.62 g N211.654 g ×100=41.40 % Sr

d) Calculating mass of Al and S  in one mole of Al2S3  and the molar mass of  Al2S3 :

2 mol Al ×26.982gmol=53.964 g Al

3 mol S ×32.065gmol=96.195 g O

Molar mass of Al2S3= 53.964+96.195=150.159 g/mol

Calculating percent composition of Al and S as:

% Al=53.964 g Al150.159  g ×100=35.94 % Al

% S=96.195 g S150.159 g ×100=64.06 % S

Conclusion:

We can find the percent composition of each element present in a given compound by using atomic weights and mole ratio.

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!

Chapter 7 Solutions

Chemistry: An Atoms-Focused Approach

Ch. 7 - Prob. 7.11QACh. 7 - Prob. 7.12QACh. 7 - Prob. 7.13QACh. 7 - Prob. 7.14QACh. 7 - Prob. 7.15QACh. 7 - Prob. 7.16QACh. 7 - Prob. 7.17QACh. 7 - Prob. 7.18QACh. 7 - Prob. 7.19QACh. 7 - Prob. 7.20QACh. 7 - Prob. 7.21QACh. 7 - Prob. 7.22QACh. 7 - Prob. 7.23QACh. 7 - Prob. 7.24QACh. 7 - Prob. 7.25QACh. 7 - Prob. 7.26QACh. 7 - Prob. 7.27QACh. 7 - Prob. 7.28QACh. 7 - Prob. 7.29QACh. 7 - Prob. 7.30QACh. 7 - Prob. 7.31QACh. 7 - Prob. 7.32QACh. 7 - Prob. 7.33QACh. 7 - Prob. 7.35QACh. 7 - Prob. 7.36QACh. 7 - Prob. 7.37QACh. 7 - Prob. 7.38QACh. 7 - Prob. 7.39QACh. 7 - Prob. 7.40QACh. 7 - Prob. 7.41QACh. 7 - Prob. 7.42QACh. 7 - Prob. 7.43QACh. 7 - Prob. 7.44QACh. 7 - Prob. 7.45QACh. 7 - Prob. 7.46QACh. 7 - Prob. 7.47QACh. 7 - Prob. 7.48QACh. 7 - Prob. 7.49QACh. 7 - Prob. 7.50QACh. 7 - Prob. 7.51QACh. 7 - Prob. 7.52QACh. 7 - Prob. 7.53QACh. 7 - Prob. 7.54QACh. 7 - Prob. 7.55QACh. 7 - Prob. 7.56QACh. 7 - Prob. 7.57QACh. 7 - Prob. 7.58QACh. 7 - Prob. 7.59QACh. 7 - Prob. 7.60QACh. 7 - Prob. 7.61QACh. 7 - Prob. 7.62QACh. 7 - Prob. 7.63QACh. 7 - Prob. 7.64QACh. 7 - Prob. 7.65QACh. 7 - Prob. 7.66QACh. 7 - Prob. 7.67QACh. 7 - Prob. 7.68QACh. 7 - Prob. 7.69QACh. 7 - Prob. 7.70QACh. 7 - Prob. 7.71QACh. 7 - Prob. 7.72QACh. 7 - Prob. 7.73QACh. 7 - Prob. 7.74QACh. 7 - Prob. 7.75QACh. 7 - Prob. 7.76QACh. 7 - Prob. 7.77QACh. 7 - Prob. 7.78QACh. 7 - Prob. 7.79QACh. 7 - Prob. 7.80QACh. 7 - Prob. 7.81QACh. 7 - Prob. 7.82QACh. 7 - Prob. 7.83QACh. 7 - Prob. 7.84QACh. 7 - Prob. 7.85QACh. 7 - Prob. 7.86QACh. 7 - Prob. 7.87QACh. 7 - Prob. 7.88QACh. 7 - Prob. 7.89QACh. 7 - Prob. 7.90QACh. 7 - Prob. 7.91QACh. 7 - Prob. 7.92QACh. 7 - Prob. 7.93QACh. 7 - Prob. 7.94QACh. 7 - Prob. 7.95QACh. 7 - Prob. 7.96QACh. 7 - Prob. 7.97QACh. 7 - Prob. 7.98QACh. 7 - Prob. 7.99QACh. 7 - Prob. 7.100QACh. 7 - Prob. 7.101QACh. 7 - Prob. 7.102QACh. 7 - Prob. 7.103QACh. 7 - Prob. 7.104QACh. 7 - Prob. 7.105QACh. 7 - Prob. 7.106QACh. 7 - Prob. 7.107QACh. 7 - Prob. 7.108QACh. 7 - Prob. 7.109QACh. 7 - Prob. 7.110QA
Knowledge Booster
Background pattern image
Recommended textbooks for you
Text book image
Chemistry
Chemistry
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Cengage Learning
Text book image
Chemistry
Chemistry
ISBN:9781259911156
Author:Raymond Chang Dr., Jason Overby Professor
Publisher:McGraw-Hill Education
Text book image
Principles of Instrumental Analysis
Chemistry
ISBN:9781305577213
Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:Cengage Learning
Text book image
Organic Chemistry
Chemistry
ISBN:9780078021558
Author:Janice Gorzynski Smith Dr.
Publisher:McGraw-Hill Education
Text book image
Chemistry: Principles and Reactions
Chemistry
ISBN:9781305079373
Author:William L. Masterton, Cecile N. Hurley
Publisher:Cengage Learning
Text book image
Elementary Principles of Chemical Processes, Bind...
Chemistry
ISBN:9781118431221
Author:Richard M. Felder, Ronald W. Rousseau, Lisa G. Bullard
Publisher:WILEY