Question

A 126.1-gram block of granite at 92.6°C is dropped into a tub of water at 24.7°C in an isolated system. The final temperature of both the granite and the water is 51.9°C. The specific heat capacity of granite is 0.795 joules/gram degree Celsius, and the specific heat capacity of water is 4.186 joules/gram degree Celsius.
The granite block transferred 1.____ of energy, and the mass of the water is 2.____ .Copy


1
A. 21,500 joules
B. 6,810 joules
C. 4,080 joulesCopy


2
A. 189 grams
B. 55.8 grams.
C. 35.8 grams

Answer 1

The granite block transferred 4080 J of energy, and the mass of the water is 35.8 g.

1. Energy from granite block

The formula for the heat (q) transferred is

q = mCΔT

m = 126.1 g; C = 0.795 J·°C⁻¹g⁻¹; ΔT = T_f – T_i = 51.9 °C - 92.6 °C = -40.7 °C

∴ q = 126.1 g × 0.795 J·°C⁻¹g⁻¹ × (-40.7 °C) = -4080 J

The granite block transferred 4080 J.

2. Mass of water

q = mCΔT

m = q/(CΔT)

q = 4080 J; C = 4.186 J·°C⁻¹g⁻¹; ΔT = T_f – T_i = 51.9 °C – 24.7 °C = 27.2 °C

∴ m = 4080 J/(4.186 J·°C⁻¹g⁻¹ × 27.2 °C) = 35.8 g

The mass of the water is 35.8 g.