Solution Concentrations Worksheet (Section 12.3)
Name ________________________ Period:
Measuring Concentration: There are several different ways to measure and express the concentration of a
solution. Molarity (Section 12.3) the term we learned earlier, refers to the concentration of a solution
expressed in moles of solute per liter of solution. We also use several other units, including the following:
1. Percent by Mass
(g)solution of mass
(g) solute of mass
x100%
2. Percent by Volume
(mL)solution of volume
(mL) solute of volume
x100%
3. Mass/Volume Percent
!
mass of solute (mg)
volume of solution (dL)
x100% (units are used in medicine)
4. Parts per million
solution of g 10 x 1
solute of g 1
6
For this type of unit, these equivalents work for water solutions:
1 ppm = 1 mg/L 1 ppb = 1µg/L 1 ppt = 1 ng/L
ppm = parts per million ppb = billion ppt = trillion
5. Molality
(kg)solvent of mass
(mol) solute ofamount
this unit is independent of temperature
Problems – Do work on Separate Paper. Show Dimensional Analysis.
1. 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 g of water? Do you need to know the formula of glucose? Why or why
not?
2. What is the mass percent sucrose in a solution obtained by mixing 225 g of an aqueous solution that is
6.25% sucrose by mass with 135 g of an aqueous solution that is 8.20% sucrose by mass?
3. Determine the volume percent of toluene in a solution made by mixing 40.0 mL toluene with 75.0 mL of
benzene.
4. What is the concentration of Na+, in parts per million by mass, in 0.00152 M Na2SO4?
5. What is the molality of a solution prepared by dissolving 225 mg of glucose (C6H12O6) in 5.00 mL of
ethanol (density = 0.789 g/mL)
6. How many milliliters of water (density = 0.998 g/mL) are required to dissolve 25.0 g of urea (CO(NH2)2)
in order to produce a solution that is 1.65 m? (m is the abbreviation for molality)
7. Describe the process you would use in order to prepare 5.00 kg of an aqueous solution that is 8.00% NaCl
by mass.
8. What is the mass percent of solute when 4.12 g is dissolved in 100.0 g of water?
9. What is the volume percent of 10.00 g of acetone (d = 0.789 g/mL) in 1.55 L of an acetone-water
solution?
10. On average, glucose makes up about 0.10% of human blood, by mass. What is the approximation
concentration of glucose in blood in milligrams per deciliter? (You have to assume something about blood).
11. Convert 0.0035% NaCl by mass into parts per million of NaCl.
12. Convert 2.4 ppm F- into molarity of fluoride ion.
13. Calculate the molality of a solution prepared by dissolving 125 mL of pure methanol (density = 0.791
g/mL) into 275 g of ethanol.
