Question

“Salt” (NaCl) is known to be readily soluble in water, however there is a limit to its solubility. The solubility of salt in water at 25° C is 35.9 g/100 mL. (3 x 5 points) a. Explain what the value 35.9 g/100 mL means. b. Write this value as two conversion factors. c. What minimum volume of water would be necessary to dissolve 2.2 kg of salt? (Show work)

Answer 1

SOLUTION:

(A) The value 35.9 g/100 mL means that a meximum of 35.9g of NaCl will dissolve in 100mL of water at 25^oC.

(B) The conversion factors can be set as

(i) 35.9g of NaCl = 100 mL of water

or 1g of NaCl = 100 / 35.9 of water.

(ii) 100 mL of water = 35.9g of NaCl

1 mL of water = 35.9 / 100 g of NaCl

(C) From the conversion factor (i) (shown above) it is clear that to dissolve 1g of NaCl we need 100 / 35.9 = 2.78mL of water.

Hence to dissolve 2.2Kg ( 2.2 X 1000 = 2200g) of NaCl water needed = 2.78 X 2200 = 6116mL = 6.116L