calculate the enthalphy of solution of cacl29(aq) if when 11.0g of cacl2 is added to water to make 125ml of solution the tempreture increases from 25.0 to 39.2(-75.0kj/mol)
6 years ago
Answered By Naim S
11.0g CaCl2 were dissolved in water to make 125 ml solution
Q=m.c. $\bigtriangleup$? t (m=125g as density of water is 1g/ml, c= 4.19J/deg.g, change in temp $\bigtriangleup$? t=39.2-25)
Q= 125x 4.19x 14.2= 7437.25 J
number of moles of solute= m/M = 11/111 = 0.0991 moles
Enthalpy of solution $\bigtriangleup$? H= Q/n = 7437.25/0.0991 = - 75047.93J = -75.0 KJ ( notice the answer has to be negative as the dissolution of CaCl2 is exothermic
6 years ago
Answered By Naim S
11.0g CaCl2 were dissolved in water to make 125 ml solution
Q=m.c. $\bigtriangleup$? t (m=125g as density of water is 1g/ml, c= 4.19J/deg.g, change in temp $\bigtriangleup$? t=39.2-25)
Q= 125x 4.19x 14.2= 7437.25 J
number of moles of solute= m/M = 11/111 = 0.0991 moles
Enthalpy of solution $\bigtriangleup$? H= Q/n = 7437.25/0.0991 = - 75047.93J = -75.0 KJ ( notice the answer has to be negative as the dissolution of CaCl2 is exothermic