How much heat is needed to raise the temperature of 9g of water by 20C

753.48 J

Explanation:

To increase the temperature of of m grams of water by n°C, you need to provide it with:

heat = m x n x specific heat

This will account for increasing the temperature of the first gram of water by n°C until you reach m grams of water.

q = mcΔT

where q = heat absorbed,

m = mass of sample,

c = specific heat of the substance; and

ΔT = the change in temperature

We know that the specific heat of water is 4.186 joule/gram °C so putting the values in the formula to get:

q = 9 x 4.186 x (20 - 0) = 753.48 J