PROBLEMS
A 10.00 gram sample of a mixture of potassium bromide (KBr) and sand was obtained.
Water was added to the mixture to dissolve the KBr as KBr is soluble in water. When the
sand was filtered and dried, it was found to weigh 3.595 g. Assume that no sand was lost
during the experimental process and that the sand was completely dried. Determine the
percentages of sand and KBr in the original sample. Show your calculations clearly.
% sand:
Calculation:

% Mass of sand = 35.95%

% Mass of KBr = 64.05%

Explanation:

From the question given, we obtained the following:

Mass of mixture( KBr + sand) = 10g

Mass of sand = 3.595g

Mass of KBr = 10 — 3.595 = 6.405g

% Mass of sand = ( Mass of sand / mass of mixture) x 100

% Mass of sand = (3.595 / 10) x100

% Mass of sand = 35.95%

We can obtain the percentage of KBr by subtracting the percentage of sand from 100. This is illustrated below:

% Mass of KBr = 100 — 35.95

% Mass of KBr = 64.05%