Question

Calculate the theoretical amount of CaCl2 that would be required to change the temperature of 50ml of water from room temperature 20C to 45C? Remember heat loss during the dissolution is equal to the heat capacity of water. this value is 4.184. you assume that the density of the water is 1g/ml.

Answer 1

50 mL of Water
Ti = 20C
Tf = 45C
d = 1.00 g/mL
C = 4.184 J/g * C

50 mL * 1.00g/mL = 50 g

Delta T = 45-20 = 25 C

q = m * C * T

= (50) (4.184) (25)
= - 5230 J

-5230/-82800 = 0.061 mol
Molar mass of CaCl2 = 110.98 g/mol
0.061 mol * 110.98 g/mol = 6.77 g

Answer 2

what does -82800 mean?

Answer 3

In response to susan, the -82800 is the heat of solution for CaCl2 in joules.