Question

Given: solubility (g/100g H2O)
temp degrees celcius KBR
20 65
40 80
60 90
80 100
100 110

A solution containing 10.5g of KBr in 10g of H2O at 100 degrees celcius is cooled to 40 degrees celcius.

A)calculate the g/100g H2O of KBr
B)is the solution saturated at 100 degrees celcius?
C) Is the solution saturated at 40 degrees celcius?
D) How much solid is formed during the cooling?

Answer 1

Note the correct spelling of celsius.

a) Convert 10.5 g KBr/10 g H2O to g KBr/100 g H2O, then compare with your table.
10.5 g KBr x (100 gH2O/10 g H2O) = 105 g KBr/100 g H2O. Your table says you can dissolve 110 g KBr at 100.
b)Look at the numbers.
c) Compare the numbers at 40 C.
d)If you had 110 g at 100 C and you can hold 80 g at 40C then 110-80 must be amount that crystallizes when cooled from 100 to 40.