Question

1. How much energy must be removed from a 200 g block of ice to cool it from 0 degrees C to -20 degrees C? The specific heat of ice is 2090 (J / kg⋅k)

Express your answer to two significant figures and include the appropriate units.

Answer 1

Answer: 8400 J

Step-by-step explanation:

Q = mcT (Q is heat, m is mass, c is specific heat capacity, and T is change in temperature)

200 g = 0.2 kg

Difference in two temperatures written in Celsius is the same as the difference in the same two temperatures written in Kelvin. Kelvin just has a different value for starting at absolute zero.

Q = 0.2*2090*(-20-0) = -8360 J

This means that 8360 J of energy must be removed. Writing the answer to two significant figures makes the answer 8400 J.