3.1.4.3 Applications of Hess's law

What is the enthalpy of formation of buta-1,3-diene, C₄H₆(g)?

• +112 kJ mol^–1

• –112 kJ mol^–1

• +746 kJ mol^–1

• –746 kJ mol^–1

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

The table shows the standard enthalpy of formation, Δ_fH^θ, for some of the substances in the reaction

C₂H₆(g) + 6F₂(g) ⟶ C₂F₆(g) + 6HF(g) ΔH^θ = −2898 kJ mol⁻¹

What is the standard enthalpy of formation, in kJ mol⁻¹, for HF(g)?

• −1638

• −273

• +273

• +1638

Tags

NGSS.HS-PS1-4

This question is about the reaction given below.

CO(g) + H₂O(g) ⇌ CO₂(g) + H₂(g)

Enthalpy data for the reacting species are given in the table.

The standard enthalpy change for this reaction of carbon monoxide and steam is

• +42 kJ mol⁻¹

• −42 kJ mol⁻¹

• +262 kJ mol⁻¹

• −262 kJ mol⁻¹

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

Use the information in the image to answer this question.

The standard enthalpy of combustion of butane, in kJ mol⁻¹, is

• −2880

• −2590

• −806

• −554

Tags

NGSS.HS-PS1-4

Use the information in the image to answer this question.

The value in kJ mol⁻¹ of the enthalpy of thermal dissociation when butane forms propane, hydrogen and carbon is

• −26.3

• −17.5

• +17.5

• +21.2

Use the information in the image to answer this question.

The value in kJ mol−1 for the enthalpy of combustion of propane is

• −211.7

• −419.7

• −2220

• −2878

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

The data in the image refer to the industrial production of nitric acid from ammonia.

The direct oxidation of ammonia to nitrogen dioxide can be represented by the equation

4NH₃(g) + 7O₂(g) → 4NO₂(g) + 6H₂O(g)

for which the standard enthalpy change, in kJ mol⁻¹, is

• −1139

• −1024

• −794

• −679

Tags

NGSS.HS-PS1-4

Using the information given, answer this question.

Fe₂O₃(s) + 3H₂(g) → 2Fe(s) + 3H₂O(g)

ΔH^⦵= +96 kJ mol⁻¹, ΔS^⦵ = +138 J K⁻¹ mol⁻¹

The standard enthalpy of formation of steam is

• +286 kJ mol⁻¹

• +242 kJ mol⁻¹

• −242 KJ mol⁻¹

• −286 kJ mol⁻¹

Tags

NGSS.HS-PS1-4

Using the data below, which is the correct value for the standard enthalpy of formation for TiCl₄(l)?

• −1538 kJ mol⁻¹

• −1094 kJ mol⁻¹

• −750 kJ mol⁻¹

• +286 kJ mol⁻¹

When ethanamide (CH₃CONH₂) burns in oxygen the carbon is converted into carbon dioxide, the hydrogen is converted into water and the nitrogen forms nitrogen gas.

Using the data above, which one of the following is a correct value for the enthalpy of combustion of ethanamide?

• −1823 kJ mol⁻¹

• −1183 kJ mol⁻¹

• −1000 kJ mol⁻¹

• −360 kJ mo1⁻¹

Tags

NGSS.HS-PS1-4