5.2.3 Calorimetry

Question 1

What is calorimetry?

Answer 1

An experimental method to measure enthalpy change

Question 2

What two equations are used in calorimetry to measure enthalpy change?

Answer 2

Q = mc/\T
/\H = -Q/moles

Question 3

What is the method for combustion calorimetry?

Answer 3

1. Measure 50g of water and place it in a can over the burner
2. Measure initial mass of burner and initial temperature of water
3. Light burner and stir water for 30 seconds, then extinguish burner
4. Measure final mass of burner and maximum temperature of water

Question 4

What are two sources of error in combustion calorimetry?

Answer 4

• Heat loss: most of the heat dissipates into the air instead of the water
• Incomplete combustion: this releases less heat energy than expected

Question 5

What is the method for solution calorimetry?

Answer 5

1. Pipette 25cm^3 of CuSO4(aq) into a polystyrene cup
2. Measure initial temperature of solution
3. Add 1g of Mg(s) and stir continuously
4. Measure maximum temperature of solution

Question 6

What are potential sources of error for solution calorimetry?

Answer 6

• Heat loss: most of the heat dissipates into the air instead of the water
• Incomplete combustion: this releases less heat energy than expected
• Specific heat capacity is no longer exactly 4.2 J/g/degrees C: the water being heated is not pure, as it has things dissolved in it