In: Chemistry
A 50.0-g sample of liquid water at 25.0°C is mixed with 35.0 g of water at 89.0°C. The final temperature of the water is ________°C.
According to the energy's conservation law, the heat released by the mass of hot water (35.0g,89ºC) is gained by the mass of cold water (50.0g,25ºC) and the net change in energy in the system is equal to zero. We can write it as:
In calorimetry, the heat released or gained (Q) by a pure substance when temperature is changed is given by:
Where:
Q is the heat
m is the mass of the susbtance
C is the specific heat
Tf is the final temperature
Ti is the initial temperature
Substituting equation (2) in equation (1), we have:
It can be simplified as:
Solving this equation for the final temperature (Tf), we have:
Substituting given data, the final temperature of the water is
The final temperature of the water is 51.4ºC