Concentration Calculations Practice
Concentration in Consumer Products
1. How many grams of oil are in 500 g of a gasoline-oil mix that is 5% oil? (25 g)
2. The concentration of sugar in a soft drink is measured to be 10.5%. How many grams of sugar
are in 125 g of the drink? (13.1 g)
3. Determine the volume percent of toluene in a solution made by mixing 40.0 mL toluene with
75.0 mL of benzene. (53.3 % v/v)
4. Glucose is a sugar that is found abundantly in nature. What is the percent by mass of a solution
made by dissolving 163 g of glucose in 755 mL of water? Do you need to know the formula of
glucose? Why or why not? (21.6% w/v)
5. The label on an Ocean Spray CranRaspberry drink lists 30 g of sugar in 240 mL of drink. What is
the % w/v? (12.5% w/v)
6. Which is more concentrated 34 g of salt dissolved in 100 ml of water or 100 g of salt in 1500 ml
of water? (34 g/100mL)
7. A solution is prepared by dissolving 125 g sucrose (C12H22O11) in 135 mL H2O. Calculate the mass
% of sucrose in the solution. (92.6%)
8. How many grams of K2SO4 would you need to prepare 1.5L of 5.0% K2SO4 solution? (75g)
9. Suppose 17 grams of sucrose is dissolved in 183 mL of water. What is the concentration of
sucrose in ppm? (92896 ppm)
10. The solubility of AgCl is 0.008 grams/100 grams of water. What is this concentration in ppm?
(80 ppm)
11. Helium gas, 3.0 x 10 -4 g, is dissolved in 200 mL of water. Express this concentration in parts per
million. (1.5 ppm)
12. A sample of 300.0 mL of drinking water is found to contain 38 mg Pb. What is this concentration
in parts per million? (126 ppm)
13. A solution of lead sulfate (PbSO4) contains 0.425 g of lead sulfate in 100.0 mL of water. What is
this concentration in ppm? (4250 ppm)
14. A 900.0 mL sample of sea water is found to contain 6.7 x 10 -3 g Zn. Express this concentration in
ppm. (7.4 ppm)
15. A drinking water plant adds 500 g of fluoride to a water tank containing 500,000 L of drinking
water. What is the concentration of fluoride in the water in parts-per-million (ppm)? (1ppm)
Molar Concentration (AKA Amount Concentration/Molarity)
1. Calculate molarity (moles/Liter) for a-c.
a)
57 g of NaClO3 in 300 mL of water (1.8 M)
b)
288 g of Ag2Cr2O7 in 100 mL water (6.67 M)
c)
852 g of Sn(C2H3O2)2 in 5.00 L water (0.720 M)
2. How many grams of NaOH in 0.10 L water are needed to make a 3.0 M solution? (12 g)
3. Explain how to make one liter of a 1.25 molar ammonium hydroxide solution. (43.8 g)
4. What is the molarity of a solution in which 0.45 grams of sodium nitrate are dissolved in 265 mL
of solution? (0.020 M)
5. What will the volume of a 0.50 M solution be if it contains 25 grams of calcium hydroxide?
(0.67L)
6. How many grams of ammonia are present in 5.0 L of a 0.050 M solution? (4.3g)
7. If I make a solution by adding 83 grams of sodium hydroxide to 750 mL of water…
a)
What is the molarity of sodium hydroxide in this solution? (2.7 M)
b)
What is the percent by mass of sodium hydroxide in this solution? (11% w/v)
8. What is the molarity of 10.0 g of table salt dissolved in water to make 100 mL of solution? (1.7
M)
9. What is the amount concentration of 4.80 g of citric acid (C6H8O7) dissolved in water to make
2.50 L of solution? (9.99 x 10-3 M)
Solution Stoichiometry – Balance the Equations
1. How many grams of silver chromate will precipitate when 150. mL of 0.500 M silver
nitrate are added excess potassium chromate? (12.4 g)
AgNO3(aq) + K2CrO4(aq)  Ag2CrO4(s) + KNO3(aq)
2. What volume of 0.415 M silver nitrate will be required to precipitate as silver bromide all
the bromide ion in 35.0 mL of 0.128 M calcium bromide? (5.4 mL)
AgNO3(aq) + CaBr2(aq)  Ca(NO3)2(aq) + AgBr(s)
3. What volume of 0.496 M HCl is required to neutralize 20.0 mL of 0.809 M sodium
hydroxide? (32.6 mL)
HCl(aq) + NaOH(aq)  NaCl(aq) + H(OH)(l)
4. How many mL of 0.280 M barium nitrate are required to precipitate as barium sulfate all
the sulfate ions from 25.0 mL of 0.350 M aluminum sulfate? (10.4 mL)
Ba(NO3)2(aq) + Al2(SO4)3(aq)  BaSO4(s) + Al(NO3)3(aq)