Polymers, dyes, drugs, pesticides and fertilisers, then colloids, osmosis and buffers in daily life, and the radioisotopes medicine and industry actually use.
Unit 4 carries 3 of the 50 chemistry marks; with three chapters sharing them, this one averages one (MEC publishes weights by unit, not by chapter). It is the broadest of the three and the one that borrows from everywhere — colloids and osmotic pressure come from Physical chemistry, polymers and dyes from Organic.
The MEC scope line runs: Polymers, dyes, drugs, pesticides and fertilisers. Applications of colloids, osmotic pressure and buffers in daily life. Medical and industrial applications of radioisotopes. The headings below are its points in MEC's order.
Three ways it comes: recall (the monomers of nylon-6,6, the isotope used for thyroid scans); understanding (why an antiseptic and a disinfectant are the same phenol at different strengths, why a hypertonic drip shrinks red cells); application (percentage of nitrogen in urea, choosing a buffer, reading a half-life).
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