# Problem: Two substances, lead and glass (Pyrex), initially at different temperatures, come into contact and reach thermal equilibrium. The mass of lead is 18.1 g and its initial temperature is 62.6˚C. The mass of glass (Pyrex) is 20.6 g and its initial temperature is 25.1˚C. What is the final temperature of both substances at thermal equilibrium? (The specific heat capacity of lead is 0.128 J/g•˚C; the specific heat capacity of glass (Pyrex) is 0.75 J/g•˚C.)

###### FREE Expert Solution

$\overline{){\mathbf{q}}{\mathbf{=}}{\mathbf{mc}}{\mathbf{∆}}{\mathbf{T}}}$

+qabsorbs heat
–qloses heat

Heat transfer: hot to cold

heat released by lead = heat absorbed by glass

At thermal equilibrium:

▪ final temperature of lead = final temperature of glass = final temperature of system

###### Problem Details

Two substances, lead and glass (Pyrex), initially at different temperatures, come into contact and reach thermal equilibrium. The mass of lead is 18.1 g and its initial temperature is 62.6˚C. The mass of glass (Pyrex) is 20.6 g and its initial temperature is 25.1˚C. What is the final temperature of both substances at thermal equilibrium? (The specific heat capacity of lead is 0.128 J/g•˚C; the specific heat capacity of glass (Pyrex) is 0.75 J/g•˚C.)