How many joules are required to heat 250 grams of liquid water from 0°C to 100°C?

1 Answer
May 28, 2016

Q= 104525 J

Explanation:

The key equation is

Q=mc Delta T,

where Q is the heat energy required to heat a mass, m,
though a change in temperature of Delta T and c is the heat capacity of the material (found in books!). Typical units are Q in Joules or J, m in kg and Delta T is in either Kelvin, K, or degrees Celsius ""^oC. The units of c depend on the other units used but J // kg ""^o C is typical.

we look up c for water (textbook, the internet, etc)
c=4181 J// kg ""^o C
m=250 g=0.250 kg
Delta T= T_"final" -T_"initial"=100 ""^oC-0 ""^oC=100 ""^oC

Q=(0.250 kg)(4181 J // kg ""^o C) (100 ""^o C)
Q=(0.250 cancel{kg})(4181 J // cancel{kg} cancel{""^o C}) (100 cancel{""^oC})

Q= 104525 J