Posted by
**Steve** on
.

A sample of a mixture containing only sodium chloride (NaCl) and potassium chloride (KCl) has a total mass of 4.000g. When this sample is dissolved in water and excess silver nitrate is added a white precipitate (AgCl) forms. After filtration and drying, this precipitate had a mass of 8.5904g. Calculate the mass percent of each component in the mixture.

x= g NaCl

y= g KCl

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x+y=4.000

x(1 molAgCl/1 mol NaCl)+y(1 mol AgCl/KCl) = 8.5904

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solve for x and y.

Then [(x/4.000)]*100 = %NaCl

[(y/4.000)]*100 = %KCl

Post your work if you get stuck.

58.5x + 74.5y = 4

143.5 (x+y) = 8.5904

Using system of equations,

x = 0.028 y=0.031

NaCl = 58.5*0.028 / 4 *100 = 43 %

KCl = 74.5 * 0.031 / 4 *100 = 57 %

Is this right?