a )John heats up 2kg of water from 20 degrees c to 80 degrees c. How much energy input did this require? b )When John weighs the water at the end, he has less than he started with. Why might this be? c) What hazards are in this experiment?

a) energy transferred = mass.specific heat capacity.temperature change, or E = m.c.theta. c is provided at 4181 joules per kg. so E = 2.4181.(80-20) = 501720 joules

b) some water has evaporated off as it was heated

c) 80 degree water can burn, care should be taken