SCH3U   Concentration Unit Calculations Other than Molarity     Answers
 1. Rubbing alcohol, C3H7OH(l) is sold as a 70.0% solution for external use only.  What volume of pure C3H7OH(l) is present in a 500 mL bottle? 2. Suppose your company makes hydrogen peroxide solution with a generic label for drugstores in your area.  What mass of pure hydrogen peroxide is needed to male 1000 bottles each containing 250 mL of 3.0% H2O2(aq) 3. The maximum acceptable concentration of fluoride ions in municipal water supplies is 1.5 ppm.  What is the maximum mass of fluoride ions you would get from a 0.250 L glass of water? 4. What concentration ratio is often found on the labels of consumer products?  Why do you think this unit is used instead of moles per litre? 5. Bags of a D5W intravenous sugar solution used in hospitals contains a 5.0%W/V dextrose-in-water solution. a)   What mass of dextrose is present in a 500.0 mL bag? b)   What is the concentration of D5W expressed in parts per million? 6. Bald eagle chicks living around Lake Superior were found to contain PCBs (polychlorinated biphenyls) at an average concemtration of 18.9 mg/kg.  If a chick had a mass of 0.6 kg, what mass of PCB's would it contain? 7. If the average concentation of PCB's in the body tissue of a human is 4.00 ppm, what mass of PCBs is present in a 64 kg person? 8. Each 5 mL dose of a cough remedy contains 153 mg of ammonum carbonate, 267 mg of potassium bicarbonate, 22 mg of menthol, and 2.2 mg of camphor. What is the concentrations of each of these ingredients in grams per litre? 9. An Olympic bound athlete tested positive for the anabolic steriod 'nandrolone'.  The athlete's urine test results showed one thousand times the maximum acceptable level of 2 mg/L.  What was the test result concentation in parts per million? 10. What do all concentrations units have in common? 11. Partly skimmed milk contains 2.0 grams of milk fat (MF) per 100 mL of milk.  What mass of milk fat is present in 250 mL (one glass) of milk? 12. A shopper has a choice of yogurt with three differenet concentrations of milk fat: 5.9% MF, 2.0% MF, and 1.2% MF.  If the shopper wants to limit their milk fat intake to 3.0 grams per serving, calculate the mass of the largest serving they could have for each type of yogurt. 13. Water from a well is found to have a nitrate ion concentration of 55 ppm, a level considered unsafe for drinking.  Calculate the mass of nitrate ions in 200 mL of the water. 14. The label on a bottle of "sports drink" indicated that the beverage contains water, glucose, citric acid, potassium citrate, sodium chloride, and potassium phosphate, as well as natural flavours and artificial colours.  The label also indicates that the beverage contains 50 mg of sodium ions and 55 mg of potassium ions per 400 mL serving. a)    Write chemical formulas for all of the compounds named on the label, and classify them as ionic or molecular.   Further classify the moelcules compounds as acidic, basic or neutral. b)    Which compound imparts a sweet taste to the beverage, and which imparts a tangy taste. c)     Calculate the concentration in parts per million of the sodium and potassium ions in the beverage. 15. Laboratories order hydrochloric acid as a concentrations solution (eg. 36% W/V)  What initial volume of concentrated laboratory hydrochloric acid should be diluted to prepare 5.00 L of a 0.12 mol/L solution for an experiment? 16. A 40% v/v solution of ethylene glycol in water gives an antifreeze that will protect a vehicle's cooling system to -24oC.   What volume of ethylene glycol has to be used to make 5.68 L of this solution? 17. How many grams of 4.00%(w/w) solution of KOH in water are needed to neutralize completely the acid in 10.0 mL of 0.256 M H2SO4?