SCH3U Concentration Unit Calculations Other than Molarity
SCH3U - Concentration Calculations Other than Molarity
|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? (350 mL) |
|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) |
| |(75000 mL) |
|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? |
| |(0.375 mg) |
|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? (w/v) |
|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? (25 g) |
| |b) What is the concentration of D5W expressed in parts per million? (50000 ppm) |
|6. |Bald eagle chicks living around Lake Superior were found to contain PCBs (polychlorinated biphenyls) at an average concentration of |
| |18.9 mg/kg. If a chick had a mass of 0.6 kg, what mass of PCB's would it contain? (11.34 mg) |
|7. |If the average concentration 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? |
| |(0.256 g) |
|8. |Each 5 mL dose of a cough remedy contains 153 mg of ammonium carbonate, 267 mg of potassium bicarbonate, 22 mg of menthol, and 2.2 mg|
| |of camphor. What are the concentrations of each of these ingredients in grams per litre? |
|9. |An Olympic bound athlete tested positive for the anabolic steroid 'nandrolone'. The athlete's urine test results showed one thousand|
| |times the maximum acceptable level of 2 mg/L. What was the test result concentration in parts per million? (2000 ppm) |
|10. |What do all concentrations units used in this course 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? (5.0 g) |
|12. |A shopper has a choice of yogurt with three different 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. (50.8 mL; 150 mL; 250 mL) |
|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. |
| |(0.011 g) |
|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. |
| |b) Which compound imparts a sweet taste to the beverage, and which imparts a sour taste. |
| |c) Calculate the concentration in parts per million of the sodium and potassium ions in the beverage. |
| |(Na+ = 125 ppm; K+ = 137.5 ppm) |
| | |
SCH3U - Molarity Concentration Worksheet
1. Calculate the molar concentration of the following solutions:
a. 2.8 moles of HNO3 in 4.0 L of solution
b. 0.0700 moles of NH4Cl in 50.0 L of solution
c. 25.0 grams of NaCl in 250.0 mL of solution
d. 10.0 grams of Cr(NO3)3(9H2O in 325 mL of solution
2. How many grams of the substance would be used to prepare the following solutions?
a. 1.00 L of 3.00 M NH4Cl
b. 125 mL of 0.500 M Ba(NO3)2
c. 250.0 mL of 0.100 M SbCl3
d. 2.75 L of 0.0120 M NaOH
3. How many moles of AlCl3 are contained in 350.0 mL of 0.250 M AlCl3?
4. What volume of 2.40 M HCl can be made from 100.0 g of HCl?
5. How many moles of Sr(NO3)2 are contained in 55.0 mL of 1.30 x 10-3 M Sr(NO3)2?
6. What volume of 2.8 x 10-2 M NaF contains 0.15 g of NaF?
7. The density of water at 4°C is 1.000 kg/L. What is the molar concentration of H2O in pure
water at 4°C? (Hint: how many moles of H2O are contained in 1L)
8. The density of acetic acid, CH3COOH is 1049 g/L. What is the molarity of pure acetic acid?
9. The molar concentration of pure HClO4 is 17.6 M. What is the density of pure HClO4?
10. How many grams of CaCl2 are contained in 225 mL of 0.0350 M CaCl2 solution?
11. If 1 drop (0.050 mL) of 0.20 M NaBr is added to 100.00 mL of water, what is the molarity of
the NaBr in the resulting solution?
12. Concentrated HNO3 is 15.4 M. How would you prepare 2.50 L of 0.375 M HNO3 from the
concentrated solution?
13. Concentrated H3PO4 is 14.6 M. How would you prepare 45.0 L of 0.0600 M H3PO4?
14. If 300.0 mL of solution A contains 25.0 g of KCl and 250.0 mL of solution B contains 60.0 g
of KCl, what is the molarity of the KCl in solution resulting from mixing solutions A and B?
15. If 500.0 mL of 0.750 M NaCl is boiled down until the final volume is reduced to 300.0 mL,
what is the final molarity of the NaCl? (Assume no salt is lost during the boiling process.)
16. How would you prepare 250.0 mL of 0.350 M HCl, starting with 6.00 M HCl?
17. What mass of NaCl is needed to prepare 500.0 mL of 0.400 M NaCl?
18. What volume of 12.0 M NaOH is required in order to prepare 3.00 L of
0.750 M NaOH?
19. What is the molarity of each of the following solutions?
a. 5.62 g of NaHCO3 is dissolved in enough water to make 250.0 mL
b. 184.6 mg of K2CrO4 is dissolved in enough water to make 500.0 mL
c. 0.584 g of oxalic acid (H2C2O4) is diluted to 100.0 mL
20. What mass of solid solute is present in:
a. 5.0 L of 2.5 M KBr
b. 225 mL of 0.135 M MgI2
c. 350.0 mL of 0.250 M NaCl
21. What volume of 3.00 M HCl is required to make up 5.00 L of 0.250 M HCl?
22. What volume of 15.4 M HNO3 is needed to make up 500.0 mL of 0.100 M HNO3?
23. What mass of KBr is contained in 500.0 mL of 0.235 M KBr?
24. How many moles of LiCl are contained in 5.50 L of 0.850 M LiCl?
25. What is the density of pure liquid CHBr3? (molarity = 11.4 M)
26. What volume of 0.0675 M Ba(NO3)2 contains 2.55 g of Ba(NO3)2?
SCH3U - Dilutions of Stock Solutions Worksheet
|1. |Many solutions are prepared in the laboratory from purchased concentrated solutions. What volume of concentrated 17.8 M stock |
| |sulphuric acid solution would a laboratory technician need to make 2.00 L of 0.200 M solution by dilution of the original, |
| |concentrated stock solution? (22 mL) |
|2. |In a study of reaction rates, you need to dilute copper(II) sulfate solution. You take 5.00 mL of 0.050 M CuSO4(aq) and dilute this |
| |to a final volume of 100.0 mL. |
| |a) What is the final concentration of the dilute solution? (0.0025 M) |
| |b) What mass of CuSO4(s) is present in 10.0 mL of the final dilute solution? (4.0 mg) |
| |c) Can this final dilute solution of 10 mL be prepared directly using the pure solid? Defend your answer. |
|3. |A student tries a reaction and finds that the volume of solution that reacts is too small to be measured precisely. She takes a 10.0|
| |mL volume of the solution by pipet, transfers it into a clean 250 mL volumetric flask containing some pure water, adds enough pure |
| |water to increase the volume to 250.0 mL, and mixes the solution thoroughly. |
| |a) Compare the concentration of the dilute solution to the original solution. (4%) |
| |b) Compare the volume that will react now to the volume that reacted initially. (25 X) |
| |c) Predict the speed or rate of reaction using the diluted solution compared with the rate using the original solution. Explain |
| |your answer. (25 times slower) |
|4. |A 10.00 mL sample of a test solution is diluted in an environmental laboratory to a final volume of 250.0 mL. The concentration of |
| |the diluted solution is found to be 0.274 g/L. What was the concentration of the original test solution? (6.85 |
| |g/L) |
|5. |As part of a study of reaction rates, you are to prepare two aqueous solutions of cobalt(II) chloride. |
| |a) Calculate the mass of solid cobalt(II) chloride hexahydrate you need to prepare 100.0 mL of a 0.100 mole/L cobalt(II) chloride |
| |stock solution. (2.38 g) |
| |b) Calculate how to dilute this solution to make 100.0 mL of 0.0100 mole/L cobalt(II) chloride solution. |
| |(10.0 mL of stock + 90 mL water) |
| |c) Write a list of materials, and a procedure for the preparation of the two solutions. Be sure to include all necessary safety |
| |precautions. |
|6. |In chemical analysis we often dilute stock solution to produce a required standard solution. |
| |a) What volume of a 0.400 M stock solution is required to produce 100.0 mL of a 0.100 mole/L solution. |
| |(25.0 mL) |
| |b) Write a complete procedure for the preparation of this standard solution, including specific quantities and equipment. |
|7. |By the additions of water, 30.0 mL of 6.0 M H2SO4 is diluted to 150.0 mL. What is the concentration of H2SO4 after dilution? |
| |a) 1.2 M b) 1.5 M c) 3.0 M d) 4.8 M e) 6.0 M |
|8. |By the addition of water, 40.0 mL of 8.0 M H2SO4 is diluted to 160.0 mL. What is the molarity after dilution? |
| |a) 0.50 M b) 1.0 M c) 1.6 M d) 2.0 M e) 4.0 M |
|9. |A volume, V, of concentrated hydrochloric acid, 18.0 M, is diluted by the addition of 555 mL of water so that the final concentration|
| |of acid is 2.40 molar. What is V? Take volumes as being additive. |
| |a) 74 mL b) 85 mL c) 133 mL d) 240 mL e) 4163 mL |
|10. |By the additions of water, 75.0 mL of 6.0 M H2SO4 is diluted to 150.0 mL. What is the concentration of H2SO4 after dilution? |
| |a) 1.2 M b) 1.5 M c) 3.0 M d) 4.8 M e) 6.0 M |
|11. |What volume of 6.00 mol/L nitric acid, HNO3(aq), solution is needed to make 4.2 L of 0.15 mol/L HNO3 solution? |
| |a) 1.05 L b) 168 mL c) 105 mL d) 214 mL |
|12. |What volume of water must be added to 800 L of 0.130 mol/L solution to dilute it to 0.100 mol/L? |
| |a) 1840 L b) 1040 L c) 560 L d) 240 L e) 24 L |
SCH3U - Stoichiometry Involving Solutions Worksheet
|1. |Calculate the number of mL of 2.00 M HNO3 solution required to react with 216 grams of Ag according to the equation. |
| | 3 Ag(s) + 4 HNO3(aq) ---------> 3 AgNO3(aq) + NO(g) + 2 H2O(l) |
| |(1335 mL) |
|2. |Calculate in mL the volume of 0.500 M NaOH required to react with 3.0 grams of acetic acid. The equation is: |
| | NaOH(aq) + HC2H3O2(aq) -------> NaC2H3O2(aq) + H2O(l) |
| |(100 mL) |
|3. |Calculate the number of grams of AgCl formed when 0.200 L of 0.200 M AgNO3 reacts with an excess of CaCl2. The equation is: |
| | 2 AgNO3(aq) + CaCl2(aq) -------> 2 AgCl(s) + Ca(NO3)2(aq) |
| |(5.73 g) |
|4. |Calculate the mass of AgCl formed when an excess of 0.100 M solution of NaCl is added to 0.100 L of 0.200 M AgNO3. |
| |(2.87 g) |
|5. |Calculate: |
| |a) the mass of BaSO4 formed when excess 0.200 M Na2SO4 solution is added to 0.500 L of 0.500 M BaCl2 solution, and |
| |(58.35 g) |
| |b) the minimum volume of the Na2SO4 solution needed to precipitate the Ba2+ ions from the BaCl2 solution. |
| |(1250 mL) |
|6. |A sample of impure sodium chloride weighing 1.00 grams is dissolved in water and completely reacted with silver nitrate solution. The |
| |dried precipitate of AgCl has a mass of 1.48 grams. Calculate the percentage of NaCl in the original impure sample. (58.44%) |
|7. |To neutralize the acid in 10.0 mL of 18.0 M H2SO4 that was accidentally spilled on a laboratory bench top, solid sodium bicarbonate was |
| |used. The container of sodium bicarbonate was known to weigh 155.0 g before this use and out of curiosity its mass was measured as 144.5|
| |g afterwards. The reaction that neutralizes sulphuric acid this way is as follows. |
| | H2SO4 + 2 NaHCO3 --------> Na2SO4 + 2 CO2 + 2 H2O |
| |Was sufficient sodium bicarbonate used? Calculate the maximum yield in grams of sodium sulphate. |
| |(No, 8.52 g) |
|8. |Barium nitrate and potassium sulphate solutions react and form a precipitate. What is the precipitate? How many mL of 0.40 M Ba(NO3)2 |
| |solution are required to precipitate completely the sulphate ions in 25 mL of 0.80 M K2SO4 solution? (50 mL) |
|9. |What mass of silver chloride can be precipitated from a silver nitrate solution by 200 mL of a solution of 0.50 M CaCl2? |
| |(28.66 g) |
SCH3U - More Reactions in Solution Worksheet
|1. |Ammonium sulphate is a "high-nitrogen" fertilizer. It is manufactured by reacting sulphuric acid with ammonia. In a laboratory study |
| |of this process, 50.0 mL of sulphuric acid reacts with 24.4 mL of a 2.20 M ammonia solution (ammonium hydroxide) to yield the product |
| |ammonium sulphate in solution. Calculate the molar concentration of the sulphuric acid used. |
| |(0.54 M) |
|2. |Slaked lime is sometimes used in water treatment plants to clarify water for residential use. The lime is added to an aluminum sulphate|
| |solution in the water. Fine particles in the water stick to the floc precipitate produced, and settle out with it. Calculate the |
| |volume of 0.0250 M calcium hydroxide solution that can be completely reacted with 25.0 mL of 0.25 M aluminum sulphate solution. |
| |(375 mL) |
|3. |In designing a solution stoichiometry experiment for her class to perform, a chemistry teacher wants 75.0 mL of 0.200 M iron(III) |
| |chloride solution to react completely with an excess of 0.250 M sodium carbonate solution. |
| |a) What is the minimum volume of this sodium carbonate solution needed? (90 mL) |
| |b) What would be a reasonable volume of this sodium carbonate solution to use in this experiment? Provide your reasoning. |
| |(100 mL as this 10-15% excess) |
|4. |A student wishes to precipitate all the lead(II) ions from 2.0 L of solution containing, among other substances, 0.34 M Pb(NO3)2(aq). |
| |The purpose of this reaction is to make the filtrate solution non-toxic. If the student intends to precipitate lead(II) sulphate, |
| |suggest and calculate an appropriate solute, and calculate the required mass of this solute. |
| |(78.70 g of aluminum sulphate) |
|5. |Copper(II) ions can be precipitated from waste solution by adding aqueous sodium carbonate. |
| |a) What is the minimum volume of 1.25 M Na2CO3(aq) needed to precipitate all the copper(II) ions in 4.54 L of 0.0875 M CuSO4(aq) |
| |solution? (317.80 mL) |
| |b) Suggest a suitable volume to use for this reaction. (about 350 mL) |
|6. |A 24.89 piece of zinc is placed into a beaker containing 350 mL of hydrochloric acid. The next day the remaining zinc is removed, |
| |dried, weighed, and found to have a mass of 21.62 grams. Determine the concentration of zinc chloride in the beaker. (0.14 M) |
|7. |How many millilitres of 0.300 M NiCl2(aq) solution are required to completely react with 25.0 mL of 0.100 M Na2CO3(aq) solution? How |
| |many grams of NiCO3(s) will be formed? |
| |(8.33 mL; 0.30 g) |
|8. |How many millilitres of 0.400 M CaCl2(aq) would be needed to react completely with 35.0 mL of 0.600 M AgNO3(aq) solution? |
| |(26.25 mL) |
|9. |Suppose that 30.0 mL of 0.400 M NaCl(aq) is added to 30.0 mL of 0.300 M AgNO3(aq). |
| |a) How many moles and grams of AgCl(s) would precipitate? (0.009 moles) |
| |b) What would be the concentrations of each of the remaining ions in the solution after reaction? ([Na+1] = 0.2 M; [Ag+1 ]= 0 M; |
| |[Cl-1 ]= 0.05 M; [NO3-1] = 0.15M |
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