How many joules of heat are released when 50 grams of water are cooled from 70. to 60.?

m=10g=0.01kg;

t1=80°C;

t2=60°C;

C=4.2kJ/(kg*°C); (specific heat capacity of liquid water)

E=?;

E=m*(t1-t2)*C;

E=0.01kg*(80°C-60°C)*4.2kJ/(kg*°C)=0.2*4.2kJ=0.84kJ=840J;

--------------------

* represents multiplication