Enthalpy of formation

Multiple Choice

Which formula is used to calculate the enthalpy change of a reaction using standard enthalpy of formation values?

• ΔH = ΣΔH°f(products) – ΣΔH°f(reactants)

• ΔH = ΣΔH°f(reactants) – ΣΔH°f(products)

• ΔH = ΣΔH°f(products) + ΣΔH°f(reactants)

• ΔH = ΣΔH°f(reactants) × ΣΔH°f(products)

Multiple Choice

Which of the following best describes the concept of enthalpy (ΔH)?

• The energy required to break a chemical bond

• The heat content of a system at constant pressure

• The temperature change during a reaction

• The mass of reactants in a chemical reaction

Multiple Select

Which statements about standard molar enthalpy of formation are correct?

• It is the enthalpy change when 1 mol of compound is formed from elements under standard conditions.

• By definition, ΔH°f = 0 for elements in their standard states.

• It is always a positive value for all compounds.

• It is used to calculate the enthalpy change of reactions.

Multiple Choice

What is the standard enthalpy of formation (ΔH°f) for HF(g) according to the table?

• -21 kJ/mol

• -273 kJ/mol

• -396 kJ/mol

• -1220 kJ/mol

Open Ended

Using the enthalpy values from the table, calculate the enthalpy change for the reaction: S(s) + 3F2(g) → SF6(g).

Multiple Choice

Find the (ΔH°rxn) for the equation in the diagram

• -1500 kJ
• -1745 kJ

• -500 kJ
• -800 kJ

Multiple Choice

CH₄ + 2O₂ → CO₂ + 2H₂O

Find the (ΔH°rxn) for the equation

• -732 kJ
• -500 kJ
• -1000 kJ
• -891 kJ

Multiple Select

Which of the following are Sustainable Development Goals (SDGs) as shown in the image?

• No poverty

• Quality education

• Climate action

• Space exploration

Multiple Choice

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

Multiple Choice

How do you calculate overall Enthalpy of a reaction from enthalpies of formations?

• ΔHrxn = ΔHf _products - ΔHf_reactants

• ΔT = q / mC

• ΔG = ΔH -TΔS

• ΔErxn = ΔF_products x ΔF_reactants

Multiple Choice

What is the most stable form of Carbon?

• Graphite

• Diamond

• Buckyball

• None of these

Multiple Choice

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

• Fe₂(g)

• H₂O(g)

• CO(g)

• N₂(g)