Calorimetry & enthalpy worksheet with answers

Free printable Calorimetry & enthalpy worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
waterm = 150 gT1​ = 11 °C → T2​ = 90 °Cq = ?

How much heat q is needed to warm 150 g of water from 11 °C to 90 °C? The specific heat of water is 4.18 J/(g·°C). Give the answer in kJ.

m = 150 gT1 = 11 °CT2 = 90 °Cc = 4.18 J/(g·°C)
q = kJ
2.Easy
waterm = 150 gT1​ = 18 °C → T2​ = 85 °Cq = ?

How much heat q is needed to warm 150 g of water from 18 °C to 85 °C? The specific heat of water is 4.18 J/(g·°C). Give the answer in kJ.

m = 150 gT1 = 18 °CT2 = 85 °Cc = 4.18 J/(g·°C)
q = kJ
3.Medium
Tf​ = ?Ironm = 75 gT = 120 °Cc = 0.449 J/(g·°C)Waterm = 200 gT = 24 °Cc = 4.18 J/(g·°C)

A 75 g block of iron (c = 0.449 J/(g·°C)) at 120 °C is dropped into 200 g of water (c = 4.18 J/(g·°C)) at 24 °C in an insulated cup. Find the final temperature Tf.

mmetal = 75 gcmetal = 0.449 J/(g·°C)Tmetal = 120 °Cmwater = 200 gTwater = 24 °Ccwater = 4.18 J/(g·°C)
Tf = °C
4.Medium
Tf​ = ?Leadm = 50 gT = 130 °Cc = 0.129 J/(g·°C)Waterm = 400 gT = 19 °Cc = 4.18 J/(g·°C)

A 50 g block of lead (c = 0.129 J/(g·°C)) at 130 °C is dropped into 400 g of water (c = 4.18 J/(g·°C)) at 19 °C in an insulated cup. Find the final temperature Tf.

mmetal = 50 gcmetal = 0.129 J/(g·°C)Tmetal = 130 °Cmwater = 400 gTwater = 19 °Ccwater = 4.18 J/(g·°C)
Tf = °C
5.Hard
H20 g C3​H8​C3​H8​ + 5O₂reactants3CO₂ + 4H₂O(l)productsq = ?

Use the standard enthalpies of formation to find the heat q released when 20 g of C3H8 (M = 44.1 g/mol) burns completely: C3H8 + 5O₂ → 3CO₂ + 4H₂O(l). Give q as a positive number.

ΔH°f(C3H8) = −103.8 kJ/molΔH°f(CO₂) = −393.5 kJ/molΔH°f(H₂O, l) = −285.8 kJ/molΔH°f(O₂) = 0
q = kJ
6.Hard
H2C2​H6​ + 7O₂reactants4CO₂ + 6H₂O(l)productsΔH° = ?

Use the standard enthalpies of formation to find ΔH° for the reaction 2C2H6 + 7O₂ → 4CO₂ + 6H₂O(l).

ΔH°f(C2H6) = −84.7 kJ/molΔH°f(CO₂) = −393.5 kJ/molΔH°f(H₂O, l) = −285.8 kJ/molΔH°f(O₂) = 0
ΔH° = kJ

Answer key

  1. 1. q = 49.53 kJ
  2. 2. q = 42.01 kJ
  3. 3. Tf = 27.72 °C
  4. 4. Tf = 19.43 °C
  5. 5. q = 1007 kJ
  6. 6. ΔH° = −3119 kJ

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