|Concentration Calculations Other than Molarity
|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?
|| 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)
||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?
||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?
||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?
||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?
||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?
||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?
||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?
||What do all concentrations units have in common?
||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?
||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.
||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.
||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.
||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?
||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?
||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?