Question

How many joules of energy are necessary to heat a sample of water with a mass of 46.0 grams from 0.0 Celsius to 100.0 Celsius? (Use 4.184 J/g Celsius for the specific heat of water.)
Type the correct answer to 3 significant digits. If the answer has an exponent, type the number, then ^, then the exponent.

(The question is on the picture.)

Answer 1

In this situation you are meant to use the equation:
Q= cmΔT

Where Q = heat added
C = specific heat
m = mass
ΔT = change of temp. (final temp - initial temp)

for this problem
c = 4.184 J/g°C
m = 46.0 g
ΔT = (100°C - 0°C) = 100°C

So,
Q = 4.18 J/g°C * 46.0 g * 100°C
the units g and °C cancel out. and we're left with
Q = 4.18 J * 46.0 * 100  = 19228 Joules