16 flashcards · Shared on 19 August 2026 by AtomAI Library
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What is an exothermic reaction?
A reaction that transfers energy from the reacting system to the surroundings
What is an exothermic reaction?
A reaction that transfers energy from the reacting system to the surroundings
What effect does a catalyst have on the enthalpy change of a reaction?
It does not change ΔH
Which sign does ΔH have for an exothermic reaction?
Negative
If a reaction transfers −50 kJ when 2.0 mol of reactant reacts, what is the molar enthalpy change?
−25 kJ mol⁻¹
How is the enthalpy change of a reaction calculated from the enthalpies of the reactants and products?
ΔH = Hproducts − Hreactants
What is an endothermic reaction?
A reaction that absorbs energy from the surroundings
What usually happens to the temperature of the surroundings during an exothermic reaction in an insulated container?
It increases because the surroundings gain energy
In a simple calorimetry experiment, which equation calculates the energy gained by a solution?
q = mcΔT
On an energy profile for an endothermic reaction, how do the products compare with the reactants?
The products have higher enthalpy
Using mean bond enthalpies, which expression estimates the enthalpy change of a reaction?
Energy of bonds broken − energy of bonds formed
Which statement about forming chemical bonds is correct?
Bond formation releases energy
A reaction heats 100 g of solution by 5 °C. If the solution has a specific heat capacity of 4.18 J g⁻¹ °C⁻¹, how much energy does the solution gain?
2,090 J
What is the activation energy of a reaction?
The minimum energy needed for particles to react successfully
If the forward reaction has ΔH = −80 kJ mol⁻¹, what is ΔH for the reverse reaction?
+80 kJ mol⁻¹
Which statement about breaking chemical bonds is correct?
Bond breaking requires energy and is endothermic
Which process is endothermic?
Thermal decomposition of calcium carbonate