CONCENTRATION OF SOLUTIONS

1. How many grams of glucose are needed to prepare 400mL of 5% glucose solution?

• a. 5g

• b. 10g

• c. 14g

• d. 20g

2. Brass is a copper- zinc alloy. If the concentration of zinc is relatively low, the brass has a golden color and is often used for inexpensive jewelry. If a 35.0g pendant contains 1.7g of zinc, what is the % by mass of zinc in brass?

• a. 4.7%

• b. 4.8%

• c. 4.9%

• d. 10%

Tags

NGSS.HS-PS1-7

3. What is the percent by mass concentration of a solution that contains 6.0g of sugar dissolved in 20.7g of water?

• a. 21.21%

• b. 22.21%

• c. 22.47%

• d. 22.74%

4. What is the percentage concentration in the following solution given 2g sucrose in 80g water?

• a. 2.4%

• b. 2.5%

• c. 4.0%

• d. 97.6%

5. Sterling silver contains 95% silver. If a necklace made of sterling silver weighs 15g, what is the mass of the silver dissolved in the necklace?

• a. 1.6g

• b. 6.2g

• c. 9.0g

• d. 14.25g

6. What is the % M/M if 10.0g of copper is added to enough zinc to produce 110g of an alloy?

• a. 9.05%

• b. 9.09%

• c. 9.10%

• d. 10.00%

Tags

NGSS.HS-PS1-7

7. You bought an 18 karats ring which contains 18g of gold. What is the % by mass of gold in a ring?

• a. 65%

• b. 75%

• c. 85%

• d. 95%

8. What is the volume of a 25% methyl solution that contains 20mL of methyl?

• a. 6.25mL

• b. 7.25mL

• c. . 8.25mL

• d. 9.25mL

9. A solution is prepared by mixing a 20g of sodium chloride in 80g of water. What are the concentrations of the solute and solvent in % by mass?

• a. solute: 10% ; solvent: 90%

• b. solute: 20% ; solvent: 80%

• c. solute: 30% ; solvent: 70%

• d. solute: 40% ; solvent: 60%

10. A solution of benzene and toluene was prepared by adding toluene to benzene until the total volume becomes 135mL. By volume, the solution is 30.0% benzene. How much benzene, in mL, is in the solution?

• a. 39.5mL of benzene

• b. 40.5mL of benzene

• c. 41.5mL of benzene

• d. 42.5mL of benzene