PRACTICE: Mass %, Molarity, and Dilutions

Question 1

A student prepares a solution of 5.00g of NaF dissolved in 95.0g of H₂O. What is the mass/mass% concentration?

Answer 1

5%

Question 2

When 40.0g of isopropyl alcohol are dissolve into 160.0g of H₂O, what is the mass percent of alcohol in the solution?

Answer 2

20%

Question 3

If you have 5.0 milligrams of sodium chloride, and need to make a solution that is 0.2 %m/m, how many grams of water should be added?

Answer 3

2.495g

Question 4

What is the molarity of this solution: 0.25 mol of NaCl in 300mL of solution

Answer 4

0.83M

Question 5

What is the molarity of this solution: 60g of NaOH in 250mL of solution.

Answer 5

6M

Question 6

How much 2.5mol/L sulfuric acid should you use if you need 0.12 mol H₂SO₄?

Answer 6

0.048L

Question 7

How many moles of NaOH are in 38mL of 0.50 mol/L NaOH?

Answer 7

0.019mol

Question 8

How many grams of magnesium bromide are need to make 1.0L of a 4.0M magnesium bromide solution?

Answer 8

736.4g

Question 9

A 0.8M HCl was diluted to a final volume of 500mL. If the new concentration is 0.20M, what was the original volume of the solution?

Answer 9

125mL

Question 10

If you dilute 15 mL of a 12.0M HCl solution to make 2.50M HCl solution, what will the final volume be?

Answer 10

72mL

Question 11

350mL of water was added to 225mL of a 4.5M NaOH solution. What is the new concentration of the solution?

Answer 11

1.761M