Download Quiz 5 - Solution

CHEM 121
Solutions
Your Name:______________
1. What is the molarity if you dissolve 0.695 mol of potassium hydroxide (KOH) in
500mL of water?
2. What is the molarity if you dissolve 1.25g of Na3N in 125 mL of water?
3. Determine the molarity if you dissolve 100mL of ethanol (D = 0.791 g/mL, C2H6O)
in enough water to make 250mL of solution.
4. How would the molarity change if 100mL ethanol was added to 250mL of water?
Show your calculation.
5. How much sodium hydroxide (NaOH) is needed to make 250 mL of 0.5M solution?
6. Determine the (w/w)% if 5g KNO3 is dissolved in 25g of water.
7. What is the (w/v)% of 200 mg aspirin dissolved in 10mL ethanol?
8. How does the solution from problem 7 differ if (w/w)% was determined. The density
of ethanol is 0.791 g/mL.
9. How much sulfuric acid (H2SO4) in mL do you need to add to water to get 100 mL of
a 33% solution (v/v)%?
10. You have a stock solution of 3.0M of NaCl. You need to prepare 300 mL of a 0.1M
solution. How much of the stock solution do you have to dilute?
11. You have a stock solution of 1.2M HCl(aq). You measure out 10mL and dilute it to
500mL. What is your final concentration?
12. You have to perform analysis of a blood sample of a patient with a possible drug
overdose. The sample was too concentrated, so you diluted 1mL of the sample to
250mL. The concentration of the diluted sample comes out to 15 ppm. What was the
concentration of the original sample?
13. A patient should have 50mg of an antibiotic administered every 4 hours. The drug
comes in a suspension of 200 mg per 10 mL. What volume would the patient receive
every 4 hours?
14. A patient should receive an anti-inflammatory drug at a rate of 140 units per hour.
The IV bag supplies 2000 units in 500 mL. What should the flow rate be?