Question

Putting up 98 points! Will give medal

3. A calorimeter contains 500 g of water at 25°C. You place a hand warmer containing 200 g of liquid sodium acetate inside the calorimeter. When the sodium acetate finishes crystallizing, the temperature of the water inside the calorimeter is 39.4°C. The specific heat of water is 4.18 J/g-°C. How much energy was needed to heat the water?

Answer 1

Energy=specific heat of water x mass of water x water's temperatures

=4.18x500x(39.4-25)

=30096J

Answer 2

A calorimeter contains 500 g of water at 25°C.....

the temperature of the water inside the calorimeter is 39.4°C.....

The specific heat of water is 4.18 J/g-°C.

energy needed to heat the water = specific heat * mass * temp difference

= 4.18 J/g-°C * 500 g * (39.4°C - 25°C)

= 4.18*500*14.4

= 30096J

or approx. 30kJ