posted by chester .
How much energy is needed to increase the temperature of 500g of lead from 20 degrees celcius to 45. The specific heat heat capacityof lead is 128J/kg/degrees celcius
just work with the units you have
500g = .5 kg
Your temp change is 25°C
.5kg * 25°C * 128J/kg-°C = 1600J
If you keep units in mind, you will be better able to determine how they combine.