Calorimetry and Enthalpy Flashcards
Calorimetry
- Science of measuring heat
- Based on observing the temperature change when a body absorbs or releases energy as heat
Calorimeter
A device that can be used to measure thermal energy changes in a chemical reaction
Specific Heat Capacity
- Quantity of thermal energy required to raise the temp of 1 gram of a substance by 1℃
What’s the SI unit for specific heat capacity?
J/g℃
What does high specific heat capacity mean?
The substance requires a larger amount of thermal energy to raise the temp and take a longer time to cool
What does low specific heat capacity mean?
The substances takes less thermal energy to raise the temp and is quicker to cool down
First assumption made to simply calculations
Any thermal energy transferred from the calorimeter to the outside environment is negligible
Second assumption made to simply calculations
Any thermal energy absorbed by the calorimeter itself is negligible
Third assumption made to simply calculations
- All dilute, aqueous solutions have the same density (1.00g/ml)
- and same specific heat capacity as water (4.18g/J℃)
Equation used in calorimetry
- q=mcΔT
-Used to calculate total amount of thermal energy absorbed or released by the chemical system
2 Parts of value “q”
- Magnitude
- Sign
Magnitude
Calculated value
Sign
Indicates the type of thermochemical reaction
Enthalpy Definition
- Sum of internal energy
- Product of pressure and volume
What happens when a process occurs at a constant pressure?
The heat involved is equal to the change in enthalpy
