1. Calorimetry
Thermochemistry pt2

2. Calorimetry
Measure of heat flow

3. Heating different objects
If all these objects gain the same amount of heat, will they all be the same temperature?

4. Heat required to raise temp of object by 1K (or 1°C)
The temperature change of an object when specific amount of heat absorbed is determined by
HEAT CAPACITY (c)
Heat required to raise temp of object by 1K (or 1°C)

5. J/g-K J/g-°C Specific Heat Capacity
(often referred to as Specific Heat, cs)
Amount of energy required to raise the temperature of 1g of object by 1K (or 1°C)
J/g-K
J/g-°C
The ΔT in Kelvin is equal to ΔT in Celsius

7. q = mcΔT Change in temp mass heat Specific heat
Look at specific heat chart, if all substances were given the same quantity of heat, which would undergo the greatest temperature change?

8. Sample:
a)How much heat is needed to warm 250g of water from 22°C to 98°C?
b) What is the molar heat capacity of water?

9. STOP

10. Calorimeter Device used to measure heat flow Coffee cup calorimeter
Reaction occurs under constant pressure (from atmosphere)
Coffee cup calorimeter
Reactants and products are system
Water (solvent) which they are dissolved in is part of surroundings

11. Coffee cup calorimeter
Heat transfer between system (reactants+products) and surroundings (water from soln)
System is exothermic, what happens to temp of solution?
TEMP INCREASES
System is endothermic, what happens to temp of solution?
TEMP DECREASES