The specific heat of iron is 0.11 cal/g.°C. Iron melts at 1530 °C. How much heat must be added to 1.0 g of iron at 25 °C to completely melt?

You must add 170 cal to melt the iron.

The formula for the heat required is

##q = mcΔT##

##ΔT = "1530 °C – 25 °C" = "1505 °C"##

Hence

##q= mcΔT = 1.0 color(red)(cancel(color(black)("g"))) × 0.11color(white)(l) "cal"·color(red)(cancel(color(black)("g"^(-1)"°C"^(-1)))) × 1505 color(red)(cancel(color(black)("°C"))) = "170 cal"## (2 significant figures)