Thermochemical Changes
Measuring and explaining the energy absorbed or released when chemical bonds change.
9 questions, free, marked as you go with a worked explanation on every one.
What this covers
- enthalpy change calculations
The questions
- In an exothermic reaction, what is true of the enthalpy change?
- How much heat is absorbed when 100.0 g of water is warmed by 25.0 °C? Use c = 4.19 J/(g·°C).
- The molar enthalpy of combustion of methane is −890 kJ/mol. How much energy is released when 2.00 mol of methane burns? Give the magnitude in kJ.
- Using standard enthalpies of formation, calculate ΔH for CH₄ + 2O₂ → CO₂ + 2H₂O. Use ΔHf: CH₄ = −74.6, CO₂ = −393.5, H₂O = −241.8, O₂ = 0 kJ/mol.
- What does a catalyst do to a reaction?
- Which statements about endothermic reactions are correct? Select all that apply.
- What does Hess's law allow you to do?
- In a bomb calorimeter experiment, the water temperature rises. What can you conclude?
- Use the table. Which process is exothermic?