Enthalpy Change
Definition
Enthalpy change refers to the amount of heat absorbed or released by a system at constant pressure during a chemical reaction.
Analogy
Think of enthalpy change as checking your bank account balance after making some transactions. If you've spent money (analogous to an exothermic reaction), your balance decreases; if you've received money (like an endothermic reaction), it increases.
Related terms
Thermochemistry: This branch of chemistry deals with studying the energy and heat associated with chemical reactions, similar to tracking all your income and expenses over time.
Heat Capacity: The amount of heat required to raise the temperature of an object by 1 degree Celsius. It's like how many cups of hot coffee it would take to warm up a cold room.
Specific Heat Capacity: The amount of heat per unit mass required to raise the temperature by one degree Celsius. Consider this as how much hot coffee you'd need for each guest at your party in order for everyone to feel warmer.
"Enthalpy Change" appears in:
Study guides (2)
Practice Questions (11)
- Given the following data about gold: ∆Hfus = 13.2 kJ/mol, ∆Hvap = 310.9 kJ/mol, what would be the enthalpy change when gold transitions from a liquid to a solid phase?
- The enthalpy change of a reaction is typically measured at:
- Which of the following statements is true about the enthalpy change of a reaction?
- The enthalpy change for a reaction can be determined experimentally using:
- Given the following data: 2S (s) + 3O₂ (g) -> 2SO₃ (g), ΔH=-790 kJ. The enthalpy change accompanying the reaction of 1 mole of S is:
- Given the following data: 2S (s) + 3O₂ (g) -> 2SO₃ (g), ΔH=-790 kJ. What is the enthalpy change for the reaction S (s) + 3/2O₂ (g) -> SO₃ (g)?
- If the enthalpy change of a reaction is -200 kJ, which of the following is true?
- Which of the following is true about the enthalpy change of a reaction?
- If the enthalpy change of a reaction is negative, which of the following is true?
- The enthalpy change for the reaction H2(g) + F2(g) → 2HF(g) is -538 kJ/mol. If the enthalpy change for the reaction H2(g) → 2H(g) is 436 kJ/mol and the enthalpy change for the reaction F2(g) → 2F(g) is 155 kJ/mol, what is the enthalpy change for the reaction 2H(g) + 2F(g) → 2HF(g)?
- What is the enthalpy change for the reaction: C2H2(g) + 5/2O2(g) → 2CO2(g) + H2O(g) given the following chemical equations: (1) C2H2(g) + 5/2O2(g) → 2CO(g) + H2O(g) ΔH = -636.1 kJ/mol; (2) CO(g) + 1/2O2(g) → CO2(g) ΔH = -283.0 kJ/mol; (3) C2H2(g) + 5/2O2(g) → 2CO2(g) + H2O(g) ΔH = -1299.5 kJ/mol?
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