2.1 Concept of enthalpy part 2

The SI unit of heat and energy is the __________.

• calorie
• heat
• joule
• watt

Match the definition below to the correct term.

The enthalpy change that takes place when one mole of a compound is formed from its elements in their standard states under standard conditions.

• The enthalpy of neutralisation

• The enthalpy of combustion

• The enthalpy of formation

• The enthalpy of reaction

What does the circle mean in ΔH°?

• Standard Conditions (T=298.15 K P=1 atm)

• Standard Temperature and Pressure (T=273.15 K P=1 atm)

• Degree K

• Degree C

Define standard enthalpy of combustion.

• Heat released when one mole of substance is burnt completely in excess oxygen.

• Heat absorbed when one mole of substance is burnt completely in excess oxygen under standard state.

• Heat released when one mole of substance is burnt completely in excess oxygen under standard state.

• Heat change when one mole of substance is burnt partially in excess oxygen under standard state.

Which of the following has a ΔH_f^o value of 0?

• Br₂(g)

• N(g)

• CO(g)

• N₂(g)

The enthalpy of combustion is the enthalpy change

• when one mole of the pure compound is formed from its elements under standard conditions

• when 1 mole of pure substance is completely burned in excess oxygen, under the given temperature and pressure of the reaction

• when 1 mole of H⁺ (aq) ions from acid reacts with 1 mole of OH^- (aq) ions from an alkali to form 1 mole of water under the stated condition of the experiment

• the magnitude of the enthalpy change of a chemical reaction depends only on the difference in the enthalpy content of the products and the reactants, and does not on how the reaction is completed

The enthalpy of neutralisation is the enthalpy change

• when one mole of the pure compound is formed from its elements under standard conditions

• when 1 mole of pure substance is completely burned in excess oxygen, under the given temperature and pressure of the reaction

• when 1 mole of H⁺ (aq) ions from acid reacts with 1 mole of OH^- (aq) ions from an alkali to form 1 mole of water under the stated condition of the experiment

• the magnitude of the enthalpy change of a chemical reaction depends only on the difference in the enthalpy content of the products and the reactants, and does not on how the reaction is completed

What is this?

• Standard enthalpy change of formation,

• Standard enthalpy change of reaction

• Enthalpy change of combustion

• Standard enthalpy change of formation

What is the name of this enthapyl change

• Enthalpy change of formation

• Enthalpy change of combustion

• Enthalpy change of reaction

• Enthalpy change of atomisation

MgCl₂(s) ---> Mg²⁺(g) + 2Cl^-(g)

This equation represents

• Enthalpy of hydration

• Enthalpy of solution

• Lattice enthalpy of dissociation

• Lattice enthalpy of formation