Question

10 g ice at 0${}^o$C is mixed with 20 g of water at 20${}^o$C. What is the temperature of mixture?

Answer 1

Heat energy required to melt the ice completely $=mL=10\times 3360J$
Maximum possible heat energy given by water $=mST(mass$\times$s.heatcapacity$\times$ change in temp.)
$=20\times 4.2\times (20-0)=1680J$
Since heat supplied by water is not sufficient to melt the ice, the temperature of mixture would remain at 0${}^o$C.