ScienceAges 16-18

Calorimetry & molar enthalpy change

Combine molar mass (n = m ÷ M) and calorimeter heat transfer to determine the magnitude of molar enthalpy of combustion |ΔH|. Review suitability for your learners before teaching.

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Worksheet StudioPractice pack · Ages 16-18

Calorimetry & molar enthalpy change

Take your time. Show your thinking.

1. Complete combustion of 60 g of a fuel (molar mass M = 120 g/mol) releases 290 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 60 g (M = 120 g/mol) · Heat Q = 290 kJ → |ΔH| = Q ÷ n
2. Complete combustion of 160 g of a fuel (molar mass M = 80 g/mol) releases 1160 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 160 g (M = 80 g/mol) · Heat Q = 1160 kJ → |ΔH| = Q ÷ n
3. Complete combustion of 400 g of a fuel (molar mass M = 100 g/mol) releases 640 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 400 g (M = 100 g/mol) · Heat Q = 640 kJ → |ΔH| = Q ÷ n
4. Complete combustion of 320 g of a fuel (molar mass M = 80 g/mol) releases 2400 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 320 g (M = 80 g/mol) · Heat Q = 2400 kJ → |ΔH| = Q ÷ n
5. Complete combustion of 4 g of a fuel (molar mass M = 20 g/mol) releases 48 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 4 g (M = 20 g/mol) · Heat Q = 48 kJ → |ΔH| = Q ÷ n
6. Complete combustion of 160 g of a fuel (molar mass M = 40 g/mol) releases 1600 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 160 g (M = 40 g/mol) · Heat Q = 1600 kJ → |ΔH| = Q ÷ n
7. Complete combustion of 40 g of a fuel (molar mass M = 20 g/mol) releases 360 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 40 g (M = 20 g/mol) · Heat Q = 360 kJ → |ΔH| = Q ÷ n
8. Complete combustion of 400 g of a fuel (molar mass M = 100 g/mol) releases 2560 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 400 g (M = 100 g/mol) · Heat Q = 2560 kJ → |ΔH| = Q ÷ n
9. Complete combustion of 50 g of a fuel (molar mass M = 100 g/mol) releases 190 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 50 g (M = 100 g/mol) · Heat Q = 190 kJ → |ΔH| = Q ÷ n
10. Complete combustion of 60 g of a fuel (molar mass M = 60 g/mol) releases 100 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 60 g (M = 60 g/mol) · Heat Q = 100 kJ → |ΔH| = Q ÷ n
11. Complete combustion of 40 g of a fuel (molar mass M = 40 g/mol) releases 640 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 40 g (M = 40 g/mol) · Heat Q = 640 kJ → |ΔH| = Q ÷ n
12. Complete combustion of 16 g of a fuel (molar mass M = 80 g/mol) releases 72 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 16 g (M = 80 g/mol) · Heat Q = 72 kJ → |ΔH| = Q ÷ n

12 questions · Seed 43 · Age guidance, not curriculum certification

View the answer key

Worksheet StudioAnswer key · Ages 16-18

Calorimetry & molar enthalpy change

Answers and reasoning. Review before teaching.

1. Complete combustion of 60 g of a fuel (molar mass M = 120 g/mol) releases 290 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
580 kJ/mol
First find moles burned: n = 60 g ÷ 120 g/mol = 0.5 mol. Then |ΔH| = 290 kJ ÷ 0.5 mol = 580 kJ/mol.
2. Complete combustion of 160 g of a fuel (molar mass M = 80 g/mol) releases 1160 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
580 kJ/mol
First find moles burned: n = 160 g ÷ 80 g/mol = 2 mol. Then |ΔH| = 1160 kJ ÷ 2 mol = 580 kJ/mol.
3. Complete combustion of 400 g of a fuel (molar mass M = 100 g/mol) releases 640 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
160 kJ/mol
First find moles burned: n = 400 g ÷ 100 g/mol = 4 mol. Then |ΔH| = 640 kJ ÷ 4 mol = 160 kJ/mol.
4. Complete combustion of 320 g of a fuel (molar mass M = 80 g/mol) releases 2400 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
600 kJ/mol
First find moles burned: n = 320 g ÷ 80 g/mol = 4 mol. Then |ΔH| = 2400 kJ ÷ 4 mol = 600 kJ/mol.
5. Complete combustion of 4 g of a fuel (molar mass M = 20 g/mol) releases 48 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
240 kJ/mol
First find moles burned: n = 4 g ÷ 20 g/mol = 0.2 mol. Then |ΔH| = 48 kJ ÷ 0.2 mol = 240 kJ/mol.
6. Complete combustion of 160 g of a fuel (molar mass M = 40 g/mol) releases 1600 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
400 kJ/mol
First find moles burned: n = 160 g ÷ 40 g/mol = 4 mol. Then |ΔH| = 1600 kJ ÷ 4 mol = 400 kJ/mol.
7. Complete combustion of 40 g of a fuel (molar mass M = 20 g/mol) releases 360 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
180 kJ/mol
First find moles burned: n = 40 g ÷ 20 g/mol = 2 mol. Then |ΔH| = 360 kJ ÷ 2 mol = 180 kJ/mol.
8. Complete combustion of 400 g of a fuel (molar mass M = 100 g/mol) releases 2560 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
640 kJ/mol
First find moles burned: n = 400 g ÷ 100 g/mol = 4 mol. Then |ΔH| = 2560 kJ ÷ 4 mol = 640 kJ/mol.
9. Complete combustion of 50 g of a fuel (molar mass M = 100 g/mol) releases 190 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
380 kJ/mol
First find moles burned: n = 50 g ÷ 100 g/mol = 0.5 mol. Then |ΔH| = 190 kJ ÷ 0.5 mol = 380 kJ/mol.
10. Complete combustion of 60 g of a fuel (molar mass M = 60 g/mol) releases 100 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
100 kJ/mol
First find moles burned: n = 60 g ÷ 60 g/mol = 1 mol. Then |ΔH| = 100 kJ ÷ 1 mol = 100 kJ/mol.
11. Complete combustion of 40 g of a fuel (molar mass M = 40 g/mol) releases 640 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
640 kJ/mol
First find moles burned: n = 40 g ÷ 40 g/mol = 1 mol. Then |ΔH| = 640 kJ ÷ 1 mol = 640 kJ/mol.
12. Complete combustion of 16 g of a fuel (molar mass M = 80 g/mol) releases 72 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
360 kJ/mol
First find moles burned: n = 16 g ÷ 80 g/mol = 0.2 mol. Then |ΔH| = 72 kJ ÷ 0.2 mol = 360 kJ/mol.

12 questions · Seed 43 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 16-18

Calorimetry & molar enthalpy change

Take your time. Show your thinking.

1. Complete combustion of 60 g of a fuel (molar mass M = 120 g/mol) releases 290 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 60 g (M = 120 g/mol) · Heat Q = 290 kJ → |ΔH| = Q ÷ n
2. Complete combustion of 160 g of a fuel (molar mass M = 80 g/mol) releases 1160 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 160 g (M = 80 g/mol) · Heat Q = 1160 kJ → |ΔH| = Q ÷ n
3. Complete combustion of 400 g of a fuel (molar mass M = 100 g/mol) releases 640 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 400 g (M = 100 g/mol) · Heat Q = 640 kJ → |ΔH| = Q ÷ n
4. Complete combustion of 320 g of a fuel (molar mass M = 80 g/mol) releases 2400 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 320 g (M = 80 g/mol) · Heat Q = 2400 kJ → |ΔH| = Q ÷ n
5. Complete combustion of 4 g of a fuel (molar mass M = 20 g/mol) releases 48 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 4 g (M = 20 g/mol) · Heat Q = 48 kJ → |ΔH| = Q ÷ n
6. Complete combustion of 160 g of a fuel (molar mass M = 40 g/mol) releases 1600 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 160 g (M = 40 g/mol) · Heat Q = 1600 kJ → |ΔH| = Q ÷ n
7. Complete combustion of 40 g of a fuel (molar mass M = 20 g/mol) releases 360 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 40 g (M = 20 g/mol) · Heat Q = 360 kJ → |ΔH| = Q ÷ n
8. Complete combustion of 400 g of a fuel (molar mass M = 100 g/mol) releases 2560 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 400 g (M = 100 g/mol) · Heat Q = 2560 kJ → |ΔH| = Q ÷ n
9. Complete combustion of 50 g of a fuel (molar mass M = 100 g/mol) releases 190 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 50 g (M = 100 g/mol) · Heat Q = 190 kJ → |ΔH| = Q ÷ n
10. Complete combustion of 60 g of a fuel (molar mass M = 60 g/mol) releases 100 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 60 g (M = 60 g/mol) · Heat Q = 100 kJ → |ΔH| = Q ÷ n
11. Complete combustion of 40 g of a fuel (molar mass M = 40 g/mol) releases 640 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 40 g (M = 40 g/mol) · Heat Q = 640 kJ → |ΔH| = Q ÷ n
12. Complete combustion of 16 g of a fuel (molar mass M = 80 g/mol) releases 72 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
Fuel: 16 g (M = 80 g/mol) · Heat Q = 72 kJ → |ΔH| = Q ÷ n

12 questions · Seed 43 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 16-18

Calorimetry & molar enthalpy change

Answers and reasoning. Review before teaching.

1. Complete combustion of 60 g of a fuel (molar mass M = 120 g/mol) releases 290 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
580 kJ/mol
First find moles burned: n = 60 g ÷ 120 g/mol = 0.5 mol. Then |ΔH| = 290 kJ ÷ 0.5 mol = 580 kJ/mol.
2. Complete combustion of 160 g of a fuel (molar mass M = 80 g/mol) releases 1160 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
580 kJ/mol
First find moles burned: n = 160 g ÷ 80 g/mol = 2 mol. Then |ΔH| = 1160 kJ ÷ 2 mol = 580 kJ/mol.
3. Complete combustion of 400 g of a fuel (molar mass M = 100 g/mol) releases 640 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
160 kJ/mol
First find moles burned: n = 400 g ÷ 100 g/mol = 4 mol. Then |ΔH| = 640 kJ ÷ 4 mol = 160 kJ/mol.
4. Complete combustion of 320 g of a fuel (molar mass M = 80 g/mol) releases 2400 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
600 kJ/mol
First find moles burned: n = 320 g ÷ 80 g/mol = 4 mol. Then |ΔH| = 2400 kJ ÷ 4 mol = 600 kJ/mol.
5. Complete combustion of 4 g of a fuel (molar mass M = 20 g/mol) releases 48 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
240 kJ/mol
First find moles burned: n = 4 g ÷ 20 g/mol = 0.2 mol. Then |ΔH| = 48 kJ ÷ 0.2 mol = 240 kJ/mol.
6. Complete combustion of 160 g of a fuel (molar mass M = 40 g/mol) releases 1600 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
400 kJ/mol
First find moles burned: n = 160 g ÷ 40 g/mol = 4 mol. Then |ΔH| = 1600 kJ ÷ 4 mol = 400 kJ/mol.
7. Complete combustion of 40 g of a fuel (molar mass M = 20 g/mol) releases 360 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
180 kJ/mol
First find moles burned: n = 40 g ÷ 20 g/mol = 2 mol. Then |ΔH| = 360 kJ ÷ 2 mol = 180 kJ/mol.
8. Complete combustion of 400 g of a fuel (molar mass M = 100 g/mol) releases 2560 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
640 kJ/mol
First find moles burned: n = 400 g ÷ 100 g/mol = 4 mol. Then |ΔH| = 2560 kJ ÷ 4 mol = 640 kJ/mol.
9. Complete combustion of 50 g of a fuel (molar mass M = 100 g/mol) releases 190 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
380 kJ/mol
First find moles burned: n = 50 g ÷ 100 g/mol = 0.5 mol. Then |ΔH| = 190 kJ ÷ 0.5 mol = 380 kJ/mol.
10. Complete combustion of 60 g of a fuel (molar mass M = 60 g/mol) releases 100 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
100 kJ/mol
First find moles burned: n = 60 g ÷ 60 g/mol = 1 mol. Then |ΔH| = 100 kJ ÷ 1 mol = 100 kJ/mol.
11. Complete combustion of 40 g of a fuel (molar mass M = 40 g/mol) releases 640 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
640 kJ/mol
First find moles burned: n = 40 g ÷ 40 g/mol = 1 mol. Then |ΔH| = 640 kJ ÷ 1 mol = 640 kJ/mol.
12. Complete combustion of 16 g of a fuel (molar mass M = 80 g/mol) releases 72 kJ of thermal energy in a calorimeter. Calculate the magnitude of the molar enthalpy of combustion |ΔH| in kJ/mol.
360 kJ/mol
First find moles burned: n = 16 g ÷ 80 g/mol = 0.2 mol. Then |ΔH| = 72 kJ ÷ 0.2 mol = 360 kJ/mol.

12 questions · Seed 43 · Age guidance, not curriculum certification