Question

Find the amount of heat required to convert 10 g of ice at $-10{}^{o}C$ to steam at $100{}^{o}C$.

Answer 1

Heat required to raise temperature of ice from $-10{}^{o}Cto0{}^{o}C$ is
$Q_1=m{s}_1\theta =10\times 0.5\times 10=50cal$
Heat required to just melt ice at $0{}^{o}C$ is $Q_2=m{L}_1=10\times 80=800cal$
Heat required to raise temperature of water from $0{}^{o}Cto100{}^{o}C$ is
$Q_3=m{s}_2\theta =10\times 1\times 100=1000cal$
Heat .required to convert water at $100{}^{o}C$ into steam is
$Q_4=m{L}_2=10\times 540=5400cal$
$Totalheat=Q_1+Q_2+Q_3+Q_4$
$=7250cal$