Dilution-Conc-probl-answ-10 - PHCY 6106 PRACTICE PROBLEMS...

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Unformatted text preview: PHCY 6106 PRACTICE PROBLEMS 2010 Dilution and Concentration 1. In preparing a solution for a wet dressing, two 0.3g tablets of potassium permanganate are dissolved in 1 gallon of purified water. What will be the percentage strength (w/v) of the solution? 0.0159% = 0.016% 2. What is the strength of a sodium chloride solution obtained by evaporating 800g of a 10% (w/w) solution to 250g? 32% 3. If two tablespoonfuls of povidone iodine solution (10% w/v) are diluted to 1 quart with purified water, what is the ratio strength of the dilution? 1:315 4. How many milliliters of water must be added to 250mL of a 25% (w/v) stock solution of sodium chloride to prepare a 0.9% (w/v) sodium chloride solution? 6694.4 mL 5. A certain product contains benzalkonium chloride in a concentration of 1:5000 (w/v). How many milliliters of a 17% solution of benzalkonium chloride should be used in preparing 4 liters of the product? 4.7mL 6. How many milliliters of water for injection must be added to 10 liters of a 50% (w/v) dextrose injection to reduce the concentration to 30% (w/v)? 6667mL 7. How many milliliters of Burow’s Solution (containing 5% w/v of aluminum acetate) should be used in preparing 2 liters of a 1:800 (w/v) solution to be used as a wet dressing? 50mL 8. If a pharmacist adds 3g of a hydrocortisone to 60g of a 5% (w/w) hydrocortisone cream, what is the final percentage strength of hydrocortisone in the product? 9.52% 9. How many milliliters of a 1% (w/v) solution of phenylmercuric nitrate may be used in preparing a 100mL prescription requiring 1:50,000 (w/v) of phenyl mercuric nitrate as a preservative? 0.2mL 10. Lactic Acid 10% (w/v) Salicylic Acid 10% (w/v) Flexible Collodion qs 15mL Sig. For war removal. Use externally as directed. How many milliliters of an 85% (w/w) solution of lactic acid with a specific gravity of 1.21 should be used in preparing the prescription? 1.5mL 11. How many milliliters of water should be mixed with 1200g of 65% (w/w) alcohol to make 45% (w/w) alcohol? 533mL 12. How many milliliters of syrup containing 85% (w/v) of sucrose should be mixed with 150mL of a syrup containing 60% of sucrose to make a syrup containing 80% (w/v) of sucrose? 600 mL 13. A pharmacist mixes 10mL of 38% (w/w) hydrochloric acid with enough purified water to make 360mL. If the specific gravity of hydrochloric aci is 1.20, calculater the percentage strength (w/v) of the resulting dilution. 1.267% or 1.3% Teixeira 1 PRACTICE PROBLEMS PHCY 6106 2010 Dilution and Concentration 14. In using isoproterenol hydrochloride solution (1:5000 w/v), 1mL of the solution is diluted to 10mL with sodium chloride injection before intravenous administration. What is the percentage concentration of the diluted solution? 0.002% 15. Zinc Oxide Calamine Petrolatum Sig. Apply. aa 2g 60g If the prescription was prepared as written, and then the prescriber wished to change the concentration of zinc oxide to 10% (w/w), (a) how many additional grams of zinc oxide should be added, and (b) how many grams of a 20% (w/w) zinc oxide ointment could be added to change the strength to 10% (w/w) of zinc oxide? 4.89g, 44g 16. How many grams of zinc oxide should be added to 3400g of a 10% zinc oxide ointment to prepare a product containing 15% of zinc oxide? 200g 17. How many grams of petrolatum (diluent) should be added to 250g of a 25% ichthammol ointment to make a 5% ointment? 1000g 18. Zinc Oxide Hydrophilic Petrolatum Purified Water Hydrophilic Ointment ad Sig. Apply to affected area. 1.5 2.5 5.0 30.0 How much zinc oxide should be added to the product to make an ointment containing 10% of zinc oxide? 1.667g 19. How many milligrams of sodium fluoride are needed to prepare 100mL of a sodium fluoride stock solution such that a solution containing 1:500,000 (w/v) of sodium fluoride results when 0.5mL is diluted to 250mL with water? 100mg 20. Four equal amounts of belladonna extract, containing 1.15%, 1.30%, 1.35%, and 1.20% of alkaloids, respectively, were mixed. What was the percentage strength of the mixture? 1.25% 21. What is the percentage of alcohol in a mixture containing 1500mL of witch hazel (14% alcohol), 2000mL of glycerin, and 5000mL of 50% alcohol? 31.9% 22. A pharmacist mixes 200g of 10% ichthammol ointment, 450g of 5% ichthammol ointment, and 1000g of petrolatum (diluent). What is the percentage of ichthammol in the finished product? 2.58% Teixeira 2 PHCY 6106 PRACTICE PROBLEMS 2010 Dilution and Concentration 23. A hospital pharmacist constitutes a vial containing 2g of piperacillin sodium to 10mL with sterile water for injection. This solution is then diluted by adding it to 100mL of 5% dextrose injection for administration by infusion. What is the concentration, in milligrams per milliliter (mg/mL), of piperacillin sodium in the infusion solution? 18.18 mg/mL 24. Calculate the percentage of alcohol in a lotion containing 2 liters of witch hazel (14% alcohol), 1 liter of alcohol (95%), and enough boric acid solution to make 5 liters. 24.6% 25. How many milliliters of a 2% (w/v) solution of lidocaine hydrochloride should be used in preparing 500mL of a solution containing 4mg of lidocaine hydrochloride per milliliter of solution? 100mL 26. Dopamine hydrochloride injection is available in 5mL ampuls containing 40mg of dopamine hydrochloride per milliliter. The injection must be diluted before administration. If a physician wishes to use sodium chloride injection as the diluent and wants a dilution containing 0.04% (w/v) of dopamine hydrochloride, how many milliliters of sodium chloride injection should be added to 5mL of the injection? 495mL 27. If an antibiotic injection contains 5% (w/v) of the drug, how many milliliters of diluent should be added to 5mL of the injection to prepare a concentration of 5mg of the antibiotic per milliliter? 45mL 28. A disinfectant concentrate for surgical instruments contains 6.5% (w/v) of a quaternary ammonium compound. What is the percentage strength of a solution resulting from the addition of 60mL of the concentrate to 1 gallon of water? 0.1% 29. You have on hand 800g of a 5% coal tar ointment and 1200g of a 10% coal tar ointment. a. If the two ointments are mixed, what is the concentration of coal tar in the finished product? 8% b. How many grams of coal tar should be added to the product to obtain an ointment containing 15% of coal tar? 164.7g 30. How many grams of sorbitol solution having a specific gravity of 1.285 and how many grams (milliliters) of water should be used in preparing 500g of a sorbitol solution having a specific gravity of 1.225? 394.73g sorbitol, 105.26g water Teixeira 3 ...
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This note was uploaded on 10/15/2010 for the course PHCY 6106 taught by Professor Teixeira during the Fall '10 term at Pima CC.

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