The number of joules released when 0.64g of steam are cooled from 125 c to 105 c is -26.112 joules
calculation
by use of Q=MCΔ T formula calculate the joules released where
Q( heat) =?
M (mass) = 0.64 g
C (specific heat capacity = 2.04 j/g/c
ΔT(change in temperature) = 105-125 =-20c
Q is therefore = 0.64 g x2.04 j/g/c x -20 c = -26.112 joules
it is okay to have negative value since the reaction is exothermic that is heat is released