Photo AI

This question is about lattice enthalpies - AQA - A-Level Chemistry - Question 1 - 2018 - Paper 1

Question icon

Question 1

This-question-is-about-lattice-enthalpies-AQA-A-Level Chemistry-Question 1-2018-Paper 1.png

This question is about lattice enthalpies. Figure 1 shows a Born–Haber cycle for the formation of magnesium oxide. Complete Figure 1 by writing the missing symbols... show full transcript

Worked Solution & Example Answer:This question is about lattice enthalpies - AQA - A-Level Chemistry - Question 1 - 2018 - Paper 1

Step 1

Complete the Born–Haber Cycle with the Missing Symbols

96%

114 rated

Answer

  1. For the ionization of magnesium (Mg): Write the reaction as follows:
ightarrow ext{Mg}^{2+}(g) + 2e^-$$ 2. For the dissociation of oxygen (O): The reaction will be: $$ rac{1}{2} ext{O}_2(g) ightarrow ext{O}(g) + e^-$$ 3. For the formation of magnesium oxide (MgO): Place it at the bottom as: $$ ext{Mg}(s) + ext{O}(g) ightarrow ext{MgO}(s)$$

Step 2

Calculate the Enthalpy Change for the Formation of Magnesium Oxide

99%

104 rated

Answer

We will use Hess's law summarizing the enthalpy changes from the given data in Table 1:

ΔHf(MgO)=ΔHat(Mg)+IE1(Mg)+IE2(Mg)+BE1(O2)+EA1(O)+EA2(O)+ΔHf(MgO)\Delta H_f\text{(MgO)} = \Delta H_{at} \text{(Mg)} + \text{IE}_1 \text{(Mg)} + \text{IE}_2 \text{(Mg)} + \text{BE}_{1}(O_2) + \text{EA}_1\text{(O)} + \text{EA}_2\text{(O)} + \Delta H_f \text{(MgO)}

Substituting values:

ΔHf(MgO)=150+736+1450+495+(−142)+(−484)+602\Delta H_f\text{(MgO)} = 150 + 736 + 1450 + 495 + (-142) + (-484) + 602

Calculating gives:

ΔHf=150+736+1450+495−142−484+602=−3888/380=−10.21 kJ mol−1\Delta H_f = 150 + 736 + 1450 + 495 - 142 - 484 + 602 = -3888/ 380 = -10.21 \text{ kJ mol}^{-1}.

Join the A-Level students using SimpleStudy...

97% of Students

Report Improved Results

98% of Students

Recommend to friends

100,000+

Students Supported

1 Million+

Questions answered

Other A-Level Chemistry topics to explore

Atomic Structure

Chemistry - AQA

Formulae, Equations & Calculations

Chemistry - AQA

The Mole, Avogadro & The Ideal Gas Equation

Chemistry - AQA

Types of Bonding & Properties

Chemistry - AQA

Molecules: Shapes & Forces

Chemistry - AQA

Energetics

Chemistry - AQA

Kinetics

Chemistry - AQA

Chemical Equilibria, Le Chateliers Principle & Kc

Chemistry - AQA

Oxidation, Reduction & Redox Equations

Chemistry - AQA

Periodicity

Chemistry - AQA

Group 2, the Alkaline Earth Metals

Chemistry - AQA

Group 7 (17), the Halogens

Chemistry - AQA

Introduction to Organic Chemistry

Chemistry - AQA

Alkanes

Chemistry - AQA

Halogenoalkanes

Chemistry - AQA

Alkenes

Chemistry - AQA

Alcohols

Chemistry - AQA

Organic Analysis

Chemistry - AQA

Organic & Inorganic Chemistry Practicals

Chemistry - AQA

Thermodynamics

Chemistry - AQA

Rate Equations

Chemistry - AQA

Equilibrium constant (Kp) for Homogeneous Systems

Chemistry - AQA

Electrode Potentials & Electrochemical Cells

Chemistry - AQA

Fundamentals of Acids & Bases

Chemistry - AQA

Further Acids & Bases Calculations

Chemistry - AQA

Properties of Period 3 Elements & their Oxides

Chemistry - AQA

Transition Metals

Chemistry - AQA

Reactions of Ions in Aqueous Solution

Chemistry - AQA

Optical Isomerism

Chemistry - AQA

Aldehydes & Ketones

Chemistry - AQA

Carboxylic Acids & Derivatives

Chemistry - AQA

Aromatic Chemistry

Chemistry - AQA

Amines

Chemistry - AQA

Polymers

Chemistry - AQA

Amino acids, Proteins & DNA

Chemistry - AQA

Organic Synthesis

Chemistry - AQA

Organic Mechanisms

Chemistry - AQA

Nuclear Magnetic Resonance Spectroscopy

Chemistry - AQA

Chromatography

Chemistry - AQA

Physical Chemistry Practicals

Chemistry - AQA

Organic Chemistry Practicals

Chemistry - AQA

;