Enthalpy Changes
Chemistry ⇒ Thermochemistry and Energetics
Enthalpy Changes starts at 10 and continues till grade 12.
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See sample questions for grade 12
Describe how calorimetry can be used to determine enthalpy changes.
Describe the difference between enthalpy of formation and enthalpy of combustion.
Explain why the enthalpy change of neutralization is always negative.
Explain why the enthalpy of atomization for diatomic gases is half the bond dissociation enthalpy.
A reaction has ΔH = +150 kJ mol-1. Is the reaction endothermic or exothermic?
A reaction has ΔH = -250 kJ mol-1. Will the temperature of the surroundings increase or decrease?
A student mixes 50.0 g of water at 25°C with a salt, causing the temperature to drop to 20°C. Is the dissolution process endothermic or exothermic?
Calculate the enthalpy change for the reaction: 2H2(g) + O2(g) → 2H2O(l), given ΔH°f[H2O(l)] = -286 kJ mol-1.
Which of the following best defines enthalpy change (ΔH)?
(1) The heat absorbed or released at constant pressure
(2) The heat absorbed or released at constant volume
(3) The total energy of a system
(4) The energy required to break a bond
Which of the following is NOT a standard condition for measuring enthalpy changes?
(1) 1 atm pressure
(2) 25°C (298 K) temperature
(3) 1 mol dm-3 concentration for solutions
(4) 100°C temperature
Which of the following is NOT a standard enthalpy change?
(1) Enthalpy of formation
(2) Enthalpy of combustion
(3) Enthalpy of precipitation
(4) Enthalpy of neutralization
Which of the following is NOT a type of enthalpy change?
(1) Enthalpy of fusion
(2) Enthalpy of combustion
(3) Enthalpy of precipitation
(4) Enthalpy of atomization
The enthalpy change when one mole of a compound is formed from its elements in their standard states is called the ________ enthalpy of formation.
The enthalpy change when one mole of a liquid is converted to vapor at its boiling point is called the enthalpy of ________.
The enthalpy change when one mole of a solid ionic compound is separated into its gaseous ions is called the ________ enthalpy.
The enthalpy change when one mole of a solute dissolves in a solvent to form an infinitely dilute solution is called the enthalpy of ________.
True or False: The enthalpy change for an exothermic reaction is always negative.
True or False: The enthalpy change of a reaction can be determined using bond enthalpies.
True or False: The enthalpy change of atomization is always positive.
True or False: The enthalpy change of fusion is the energy required to convert one mole of a solid to a liquid at its melting point.
