A calorimeter weighing 123.7g has a quantity of 20C water added to it. The combined mass of the calorimeter + cold water is 198.3g.
61g of water is heated to 60C and is poured into the calorimeter. The temperature of the mixed cold and hot water and calorimeter is 38.5C. What is the calorimeter constant?

answer choices :
a ) 148.19 b) 91.29 c) 107.75 d) 161.58

c) 107.75

Explanation:

Hot water lost = 61 g * 60C * (4.184 J g¯1 °C¯1) = 3,660

Cold water = 74.6g * 20C  * (4.184 J g¯1 °C¯1) = 1,492

The difference is 3,660 - 1,492 = 2,168

Calorimeter Constant = Heat released by burning / Change in temperature

Calorimeter Constant = 2,168 / 40C * (1.987 J g¯1 °C¯1)

Calorimeter Constant = 107.75

the law of conservation of mass states that in a chemical reaction, the total mass of reactants is equal to the total mass of products. because atoms are only rearranged in a chemical reaction, there must be the same number of sodium atoms and chlorine atoms in both the reactants and products