Problem: A mixture of NaCl and NaBr has a mass of 2.05 g and is found to contain 0.75 g of Na.What is the mass of NaBr in the mixture?

FREE Expert Solution

This is a problem where, we have two unknowns.


The mass of Na that is found in the sample comes from both the mass of NaCl and mass of NaBr.


To solve this problem, we will need molar masses of NaCl and NaBr.


Molar mass of NaCl


<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>N</mi><mi>a</mi><mi>C</mi><mi>l</mi><mspace linebreak="newline"></mspace><mi>N</mi><mi>a</mi><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mn>1</mn><mo>&#xD7;</mo><mn>22</mn><mo>.</mo><mn>99</mn><mo>&#xA0;</mo><mfrac bevelled="true"><mi>g</mi><mrow><mi>m</mi><mi>o</mi><mi>l</mi></mrow></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mn>22</mn><mo>.</mo><mn>99</mn><mo>&#xA0;</mo><mfrac bevelled="true"><mi>g</mi><mrow><mi>m</mi><mi>o</mi><mi>l</mi></mrow></mfrac><mspace linebreak="newline"></mspace><mi>C</mi><mi>l</mi><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mn>1</mn><mo>&#xD7;</mo><mn>35</mn><mo>.</mo><mn>45</mn><mo>&#xA0;</mo><mfrac bevelled="true"><mi>g</mi><mrow><mi>m</mi><mi>o</mi><mi>l</mi></mrow></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mn>35</mn><mo>.</mo><mn>45</mn><mo>&#xA0;</mo><mfrac bevelled="true"><mi>g</mi><mrow><mi>m</mi><mi>o</mi><mi>l</mi></mrow></mfrac><mspace linebreak="newline"></mspace><menclose mathcolor="#FF0000" notation="box"><mi>N</mi><mi>a</mi><mi>C</mi><mi>l</mi><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mn>58</mn><mo>.</mo><mn>44</mn><mo>&#xA0;</mo><mfrac bevelled="true"><mi>g</mi><mrow><mi>m</mi><mi>o</mi><mi>l</mi></mrow></mfrac></menclose></math>


Molar mass of NaBr


<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>N</mi><mi>a</mi><mi>B</mi><mi>r</mi><mspace linebreak="newline"></mspace><mi>N</mi><mi>a</mi><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mn>1</mn><mo>&#xD7;</mo><mn>22</mn><mo>.</mo><mn>99</mn><mo>&#xA0;</mo><mfrac bevelled="true"><mi>g</mi><mrow><mi>m</mi><mi>o</mi><mi>l</mi></mrow></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mn>22</mn><mo>.</mo><mn>99</mn><mo>&#xA0;</mo><mfrac bevelled="true"><mi>g</mi><mrow><mi>m</mi><mi>o</mi><mi>l</mi></mrow></mfrac><mspace linebreak="newline"></mspace><mi>B</mi><mi>r</mi><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mn>1</mn><mo>&#xD7;</mo><mn>79</mn><mo>.</mo><mn>90</mn><mo>&#xA0;</mo><mfrac bevelled="true"><mi>g</mi><mrow><mi>m</mi><mi>o</mi><mi>l</mi></mrow></mfrac><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mn>79</mn><mo>.</mo><mn>90</mn><mo>&#xA0;</mo><mfrac bevelled="true"><mi>g</mi><mrow><mi>m</mi><mi>o</mi><mi>l</mi></mrow></mfrac><mspace linebreak="newline"></mspace><menclose mathcolor="#FF0000" notation="box"><mi>N</mi><mi>a</mi><mi>B</mi><mi>r</mi><mo>&#xA0;</mo><mo>=</mo><mo>&#xA0;</mo><mn>102</mn><mo>.</mo><mn>89</mn><mo>&#xA0;</mo><mfrac bevelled="true"><mi>g</mi><mrow><mi>m</mi><mi>o</mi><mi>l</mi></mrow></mfrac></menclose></math>


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Problem Details

A mixture of NaCl and NaBr has a mass of 2.05 g and is found to contain 0.75 g of Na.

What is the mass of NaBr in the mixture?

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What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Mass Percent Formula concept. You can view video lessons to learn Mass Percent Formula. Or if you need more Mass Percent Formula practice, you can also practice Mass Percent Formula practice problems.

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Based on our data, we think this problem is relevant for Professor Shih's class at UML.