text: heat change per gram of potassium bromide dissolved in water? when 2.50g of potassium bromide dissolves in 1.00102g water in a calorimeter, the temperature drops from 22.657 degees celsius to 21.661 degrees celsius. what is the heat change per gram of potassium bromide dissolved in water? assume that al the heat comes from the water (c= 4.18j/g deg c) i think you mean 100.102 g of water. if not, substitute your original value into the equation below.  q = m deltat c = (100.102 g) (0.996 degc) (4.184j/g degc)     = 417.15 j  417.15 j/ 2.50 g= 166.86 j/g kbr