Question

What is the energy change when the temperature of 14.8 grams of solid lead is decreased from 38.4 °C to 23.7 °C ?

Answer 1

Answer: Q= -34.6 J

Explanation: Use Q= mc∆T

c for solid lead is equal to 0.159 J/g°C

Substitute the values:

=14.8 g(0.159J/g°C)(23.7°C-38.4 °C)

= 14.8 g(0.159J/g°C) ( -14.7°C)

= -34.6 J

Cancel out the following units: g and °C so the remaining unit is in J.