Calculating specific heat capacity

Question

A chemist carefully measures the amount of heat needed to raise the temperature of a 835.0 mg sample of a pure substance from 30.2*C to 52.1*C. The experiment shows that 85.9J of heat are needed. What can the chemist report for the specific heat capacity of the substance? Round your answer to 3 significant digits.

Answer 1

The equation we want to use for this problem is ...

q = mC∆T

q = heat = 85.9 J

m = mass in grams = 835.0 mg x 1 g / 1000 mg = 0.835 g

C = specific heat = ?

∆T = change in temperature = 52.1º - 30.2º = 21.9º

Solve for C (specific heat):

C = q / (m)(∆T) = 85.9 J / (0.835 g)(21.9º)

C = 4.70 J/gº