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 11
A chemical reaction has an enthalpy change of +75 kJ mol-1. Will the temperature of the surroundings increase or decrease?
A reaction has ΔH = -200 kJ mol-1. If the reaction is reversed, what is the enthalpy change for the reverse reaction?
Define the term 'standard enthalpy change of combustion'.
Describe the difference between enthalpy of atomization and enthalpy of formation.
Explain why bond breaking is endothermic and bond making is exothermic.
A student mixes 50.0 g of water at 25.0°C with 50.0 g of water at 75.0°C in an insulated container. Assuming no heat loss, what is the final temperature? (Specific heat capacity of water = 4.18 J g-1 K-1)
Calculate the enthalpy change for the reaction: C(s) + O2(g) → CO2(g), given the following data:
C(s) + 1/2 O2(g) → CO(g) ΔH = -110 kJ mol-1
CO(g) + 1/2 O2(g) → CO2(g) ΔH = -283 kJ mol-1
Calculate the enthalpy change when 0.5 mol of methane is burned, given that the standard enthalpy of combustion of methane is -890 kJ mol-1.
Calculate the heat evolved when 2.00 mol of H2O(l) is formed from H2(g) and O2(g). Given: 2H2(g) + O2(g) → 2H2O(l) ΔH = -572 kJ.
Which of the following best defines enthalpy change (ΔH)?
(1) The amount of heat absorbed or released at constant pressure
(2) The amount of 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 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 state function?
(1) Enthalpy
(2) Work
(3) Internal energy
(4) Entropy
Which of the following is the correct unit for enthalpy change?
(1) J
(2) kJ mol-1
(3) mol
(4) kJ
The enthalpy change when one mole of a solid ionic compound is separated into its gaseous ions is called the enthalpy of ________.
The enthalpy change when one mole of a solid is converted to a liquid at its melting point is called the enthalpy of ________.
The enthalpy change when one mole of a substance is completely burned in oxygen is called the enthalpy of ________.
The enthalpy change when one mole of a substance is dissolved in a large amount of solvent to form an infinitely dilute solution is called the enthalpy of ________.
True or False: An exothermic reaction has a negative enthalpy change.
True or False: The enthalpy change of a reaction depends on the path taken from reactants to products.
True or False: The enthalpy change of a reaction is independent of the physical states of reactants and products.
