the amount of energy (heat) required to raise the temperature of one gram of water by one Celsius degree. 1000 cal = 1 Cal joule: the SI unit. 1 cal = 4.184 J
Specific Heat Capacity
The amount of energy required to change the temperature of one gram of a substance by one Celsius degree. · Known as Specific Heat · Symbol Cp or s · Units: J/(goC) or cal/(goC) · Depends on Substance and State of Matter. · Some Common Cp’s Water (l) : 4.184 J/(goC) Water (s): 2.03 J/(goC) Aluminum: 0.89 J/(goC) Gold: 0.13 J/(goC) · Lower Cp responds faster to heating or cooling.
Specific Heat Capacity Equation
Q = s x m x (Tf – Ti) Q: Heat s: Specific Heat Capacity m: Mass Tf: Final Temperature Ti: Initial Temperature Tf – Ti = Change in Temperature (Delta T)
Heat problems involving more than one substance.
The magnitude of the heat (Q) lost by one object is equal to the magnitude of the heat (Q) gained by the other object. · One object is exothermic the other is endothermic so the Q for one is positive while the Q for the other is negative. · Since they are the same magnitude but different signs, we can say 0 = Q1 + Q2 · In fact when multiple objects all at different temperatures are mixed in a sealed system, the objects transfer heat to each other until they all reach the same final temperature. We assume no heat is lost or gained by the surroundings. 0 = Q1 + Q2 + Q3 + … Qz