How many joules are needed to change the temperature of 100 g of water from 20°C to 40°C

This is the example problem from my book. Please explain if you can, thanks!

Your equation is Q = m x c x delta T.

Q is energy (J), m is mass (g), c is the specific heat capacity of water (J/K/g) and T is temp (K)

c is just a constant for water that should be given to you = 4.18 (J/K/g)

so:

Q= 100g x 4.18J/K/g x 20K = 8360J

The formula for heat is given by;
Q = m * c * ΔT
where;
m = mass of substance
c = specific heat capacity of substance
ΔT = temperature change in kelvin
specific heat capacity of water = 4.1855 J/ (g * K)
ΔT of water = (40 - 20) = 20 + 273.15K = 293.15K
Q = 100g * 4.1855 J/(g * k) * 293.15K
Q = 122.7kJ or 122697.9J
Hope this helps
Goodluck!