In: Chemistry
When a 7.00-g sample of RbBr is dissolved in water in a calorimeter that has a total heat capacity of 3.090 kJ·K–1, the temperature decreases by 0.300 K. Calculate the molar heat of solution of RbBr.
Heat absorbed by calorimeter = (heat capacity of calorimeter)(Tf - Ti)
= (3.090 kJ / K)*(0.300 K)
= 0.927 KJ
molar mass of RbBr = 165.37 g/mole.
moles RbBr = 7.00 g / 165.37 g
= 0.0423 moles.
= 0.927 kJ heat / 0.0423 moles RbBr = +21.9 kJ / mole of
RbBr
molar heat of solution of RbBr = +21.9
KJ