A student was given a mixture of sand, ammonium chloride and sodium chloride.
Describe how the student would obtain a dry sample of each of the three substances from the mixture.[3]
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KCSE Chemistry233
2 papers160 marks4 h
What we predict comes up
From the syllabus weighting and how the papers are usually set. The papers below follow it.
- Atomic structure, periodic table and bonding16%Grid-style periodic table questions and bonding appear on both theory papers, usually as one full Paper 2 question.
- Organic chemistry and carbon14%Organic chemistry I and II usually earn a full Paper 2 question plus several Paper 1 items.
- Nitrogen, sulphur and chlorine13%Nitrogen, sulphur and chlorine and their industrial processes are among the most tested Form 3 topics.
- Electrochemistry and electrolysis11%Electrode potentials and Faraday calculations appear on both papers most years.
Paper 1 (Theory)
2 h · 80 marks · Calculator allowed
- Answer all the questions in the spaces provided.
- Mathematical tables and silent electronic calculators may be used.
- All working must be clearly shown where necessary.
Answer or mark a question and your score adds up here.
Answer all the questions80 marks
A paper chromatogram of a green dye was run in a solvent. The table shows the distance moved by the solvent and by each of three spots from the base line.
| Distance from base line (cm) | |
|---|---|
| Solvent front | 12.0 |
| Spot A | 3.0 |
| Spot B | 7.2 |
| Spot C | 9.6 |
(a)Calculate the value of spot B.[1]
(b)Which spot contains the component that is most soluble in the solvent? Give a reason.[1]
Element X has atomic number 15 and mass number 31. (X is not the actual symbol of the element.)
(a)State the number of neutrons in an atom of X.[1]
(b)Write the electron arrangement of X.[1]
(c)Write the formula of the compound formed when X reacts with hydrogen.[1]
25 more questions
Every paper, every question, the answers and the mark scheme. Free with a Knomi account.
Not included: Paper 3 (233/3), the practical examination, is left out because it is done with apparatus in a laboratory.