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ZIMSEC · Form 6 · Upper 6

Chemistry

6 topics6 with notes

ZIMSEC Form 6 · Upper 6 Cambridge Form 6 · Upper 6
Upper 6Writing A Level finals this year?Revision mode: every Chemistry past paper by year, with marking schemes, and a checklist of the whole syllabus.
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  1. Chemical energetics ΔH is negative for exothermic and positive for endothermic reactions. Standard conditions: 298 K, 100 kPa (or 1 atm), 1 mol dm⁻³. Notes 1 PDF
  1. Reaction kinetics Rate = change in concentration ÷ time. Reactions need collisions with energy ≥ activation energy and the correct orientation. The Boltzmann distribution shows that at a higher temperature many more molecules exceed the activation energy; a catalyst lowers the activation energy. Notes 1 PDF
  1. Chemical equilibria and acid–base chemistry In a closed system, forward and reverse rates are equal and concentrations remain constant. Notes 1 PDF
  1. Redox and electrochemistry Oxidation is an increase in oxidation number (loss of electrons); reduction is a decrease (gain). Rules: elements 0; O usually −2; H usually +1; the sum in a compound is 0, in an ion its charge. Notes 1 PDF
  1. The periodic table: periodicity, groups and transition elements Reactivity increases down the group. Hydroxides become more soluble and sulfates less soluble down the group; carbonates and nitrates become more thermally stable down the group (larger cations polarise the anion less). Notes 1 PDF
  1. Organic chemistry: oxygen and nitrogen compounds, polymers and analysis Primary alcohols oxidise (acidified K₂Cr₂O₇, orange → green) to aldehydes (distil off) then carboxylic acids (reflux); secondary to ketones; tertiary resist oxidation. Dehydration with concentrated acid gives alkenes; esterification with acids gives esters. Notes 1 PDF