Answer to Question #116112 in Chemistry for Vanessa

Question

How many grams of water in a cup that requires 4,500J to heat from 20C to 40C?

Answer 1

Solution:

The energy, Q, needed to increase the temperature of an object of mass m, by a temperature ΔT, where the substance's specific heat is C, is given by:

Q = m × C × ΔT

m = Q / (C × ΔT)

Here,

Q = 4500 J

C = 4.186 J/(g^∘C)

ΔT = T_final - T_initial = 40^∘C − 20^∘C = 20^∘C

Inputting:

m = (4500 J) / (4.186 J g^-1∘C^-1 × 20^∘C) = 53.75 g

m(H₂O) = 53.75 g

Answer: 53.75 grams of water.