This question is about lattice enthalpies - AQA - A-Level Chemistry - Question 1 - 2018 - Paper 1
Question 1
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
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Answer
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
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Answer
We will use Hess's law summarizing the enthalpy changes from the given data in Table 1:
