Molarity Worksheet Answers


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The equations I will use are:

M = moles of solute / liters of solution

and

MV = grams / molar mass.

Typically, the solution is for the molarity (M).

Note: Make sure you pay close attention to multiply and divide. For example, look at answer #8. Note that the 58.45 is in the denominator on the right side and in the final answer you will have 0.2 times 0.1 times 58.45.


1. (x) (1.00 L) = 28.0 g / 58.45 g mol¯1; x = 0.479 M

2. (x) (1.00 L) = 245.0 g / 98.08 g mol¯1; x = 2.498 M

3. (x) (0.4000 L) = 5.30 g / 106.0 g mol¯1; x = 0.125 M

4. (x) (0.7500 L) = 5.00 g / 40.00 g mol¯1; x = 0.167 M

5. 2.0 M = x / 10.0 L

6. 2.0 M = x / 0.0100 L

7. 0.20 M = x / 0.1000 L

8. (0.20 mol L¯1) (0.100 L) = x / 58.45 g mol¯1

9. (2.00 mol L¯1) (0.7500 L) = x / 98.08 g mol¯1

10. (18.0 mol L¯1) (x) = 2.45 g / 98.08 g mol¯1

This calculates the volume in liters. Multiplying the answer by 1000 provides the required mL value.

11. 12.0 M = 3.00 mol / x

This calculates the volume in liters. Multiplying the answer by 1000 provides the required mL value.

12. (0.250 mol L¯1) (0.100 L) = x / 74.1 g mol¯1

13. (x) (0.050 L) = 20.0 g / 97.99 g mol¯1

14. (0.50 mol L¯1) (2.50 L) = x / 74.55 g mol¯1

15. (x) (0.2500 L) = 12.0 g / 40.00 g mol¯1

16. Determine the molarity of these solutions:

a) x = 4.67 mol / 2.04 L
b) x = 0.629 mol / 1.500 L
c) (x) (10.00 L) = 4.783 g / 106.0 g mol¯1
d) (x) (0.250 L) = 0.897 g / 96.09 g mol¯1
e) (x) (0.0450 L) = 0.0348 g / 278.1 g mol¯1

17. Determine the number of moles of solute to prepare these solutions:

a) x = (2.00 mol L¯1) (2.35 L)
b) x = (0.415 mol L¯1) (0.01600 L)
c) x = (0.500 mol L¯1) (3.00 L)
d) x = (3.76 mol L¯1) (6.20 L)

18. Determine the grams of solute to prepare these solutions:

a) (0.00300 mol L¯1) (0.289 L) = x / 187.56 g mol¯1
b) (5.90 mol L¯1) (0.01600 L) = x / 331.2 g mol¯1
c) (2.75 mol L¯1) (0.508 L) = x / 41.99 g mol¯1
d) (3.76 mol L¯1) (6.20 L) = x / 61.98 g mol¯1
e) (1.00 mol L¯1) (0.500 L) = x / 74.55 g mol¯1
f) (3.50 mol L¯1) (4.35 L) = x / 110.99 g mol¯1

19. Determine the final volume of these solutions:

a) x = 4.67 mol / 3.89 mol L¯1
b) x = 4.907 mol / 0.500 mol L¯1
c) (0.348 mol L¯1) (x) = 0.783 g / 105.99 g mol¯1
d) (0.250 mol L¯1) (x) = 8.97 g / 96.01 g mol¯1
e) (5.00 mol L¯1) (x) = 48.0 g / 278.1 g mol¯1

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