# "Explain" questions — IB DP Chemistry Higher Level (2023 syllabus)

> 103 questions · chemistry

## How to answer

WHAT + WHY. Every point paired with a because. Structure: X happens because Y. This causes Z because … Assessment Objective: AO2. Every "explain" answer on this spec is marked against exactly this pattern.

## Sample questions

1. [Explain why the first ionisation energy of oxygen is lower than that of nitrogen, despite oxygen having a greater nuclea…](https://www.gradenine.co.uk/q/explain-why-the-first-ionisation-energy-019b0077)
2. [Explain why the boiling point of hydrogen fluoride (HF) is significantly higher than that of hydrogen chloride (HCl), de…](https://www.gradenine.co.uk/q/explain-why-the-boiling-point-of-09019d6e)
3. [Explain why high-density polyethylene (HDPE) has a higher melting point and greater tensile strength than low-density po…](https://www.gradenine.co.uk/q/explain-why-high-density-polyethylene-hdpe-has-0ca433ad)
4. [Explain why buckminsterfullerene (C₆₀) has a significantly lower melting point than diamond, despite both being allotrop…](https://www.gradenine.co.uk/q/explain-why-buckminsterfullerene-c-has-a-0ddf6cdb)
5. [Explain why increasing the concentration of a reactant in solution increases the rate of a chemical reaction, with refer…](https://www.gradenine.co.uk/q/explain-why-increasing-the-concentration-of-0ef7bcdd)
6. [Explain why the first ionisation energy of sulfur is lower than that of phosphorus, despite sulfur having a greater nucl…](https://www.gradenine.co.uk/q/explain-why-the-first-ionisation-energy-0fe82e8d)
7. [Explain why magnesium is a more effective reducing agent than iron, using standard electrode potentials to support your …](https://www.gradenine.co.uk/q/explain-why-magnesium-is-a-more-10369ab1)
8. [Explain why, at a given temperature, the particles in a sample of liquid water have a range of kinetic energies rather t…](https://www.gradenine.co.uk/q/explain-why-at-a-given-temperature-11ae962b)

## Related

- [IB DP Chemistry Higher Level (2023 syllabus) revision notes](https://www.gradenine.co.uk/learn/ib-dp-chemistry-higher-level-2023-syllabus)
- [IB DP Chemistry Higher Level (2023 syllabus) past papers](https://www.gradenine.co.uk/past-papers/ib-dp-chemistry-higher-level-2023-syllabus)
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