CALCULATING CALCULATING CONCENTRATION OF CONCENTRATION OF

SOLUTIONSSOLUTIONS1. Mass Percent = (mass of solute/mass of 1. Mass Percent = (mass of solute/mass of

solution)100solution)100

2. Parts per million = (mass of solute/mass 2. Parts per million = (mass of solute/mass of solution)10of solution)1066

3. Mass/volume percent = (mass of 3. Mass/volume percent = (mass of solute/mL solution)100solute/mL solution)100

4. Volume percent = (mL solute / mL 4. Volume percent = (mL solute / mL solution)100solution)100

5. Molarity = moles solute / L solution5. Molarity = moles solute / L solution

CALCULATING CALCULATING CONCENTRATION OF CONCENTRATION OF

SOLUTIONSSOLUTIONS• How many grams of a solution that is How many grams of a solution that is

32.7% by mass NaCl would contain 32.7% by mass NaCl would contain 45.0 g of NaCl?45.0 g of NaCl?

Mass % = (mass of solute /mass of Mass % = (mass of solute /mass of solution) 100solution) 100

32.7 % = (45.0 g / x )10032.7 % = (45.0 g / x )100

x = 45.0 g / 0.327x = 45.0 g / 0.327

x = mass of solution = x = mass of solution = 138 g138 g

CALCULATING CALCULATING CONCENTRATION OF CONCENTRATION OF

SOLUTIONSSOLUTIONS• How much solute is present in 756.1 How much solute is present in 756.1

mL of a 14.7% (mass/volume) HCl mL of a 14.7% (mass/volume) HCl solution?solution?

Mass/volume % = (massMass/volume % = (masssolutesolute/volume/volumesolutionsolution) ) 100100

14.7 % = (x / 756.1 mL )10014.7 % = (x / 756.1 mL )100

x = 0.147 (756.1 mL)x = 0.147 (756.1 mL)

x = mass of solute = x = mass of solute = 111g111g

CALCULATING CALCULATING CONCENTRATION OF CONCENTRATION OF

SOLUTIONSSOLUTIONS• A 350 mL sample of drinking water was A 350 mL sample of drinking water was analyzed and found to contain 0.0046 g of analyzed and found to contain 0.0046 g of sulfate salts. Calculate the concentration sulfate salts. Calculate the concentration of sulfate salts in this water sample?of sulfate salts in this water sample?

• MassMasswaterwater = density = densitywaterwater (Volume (Volumewaterwater))

= 1.00 g/mL (350 mL)= 1.00 g/mL (350 mL)

= 350 g solution = 350 g solution

ppm = (massppm = (masssolutesolute/mass/masssolutionsolution) 10) 1066

ppm = (0.0046g / 350 g ) ppm = (0.0046g / 350 g ) 101066

ppm = ppm = 13 ppm13 ppmUse ppm for trace amounts of solute.Use ppm for trace amounts of solute.

PRACTICE PROBLEMS PRACTICE PROBLEMS calculating the CONCENTRATION OF SOLUTIONScalculating the CONCENTRATION OF SOLUTIONS

___1. How many grams of a 45.0 % Mg(OH)2 solution can be made from 7.00 g of solid Mg(OH)2?

___2. How many kilograms of a 6.8% KC2H3O2 solution will contain 5.3 moles of KC2H3O2?

___3. If 134.5 g of a 25.0 % sucrose solution was prepared, how many grams of a 5.00% solution of sucrose would contain the same amount of sugar?

15.6 g15.6 g

7.6 kg7.6 kg

673 g673 g