A 100 g glass sample has specific heat 0.84 J/(g·°C). How much heat raises it by 10 °C? Assume constant specific heat and no phase change.

A) 1680 J

B) 420 J

C) 840 J

D) 84 J

Answer: C

Explanation: At approximately constant specific heat, q = mcΔT. Multiply 100 g by 0.84 J/(g·°C) and 10 °C to obtain 840 J.