CDS Chemistry · Teaching notes
Industrial and Applied Chemistry — CDS Chemistry
Industrial and Applied Chemistry has 14 past-year questions in CDS General Knowledge, from 2016 (II) to 2025 (II), and the 2024 (II) paper alone set four of them. Every question is a use or a material: which gas stores tissue, which glass makes lenses, why new concrete is kept wet, which compound is not a fertilizer. There is nothing to calculate, so the tables are the chapter. One 2024 question, on bleaching paper, is defective as printed and is marked where it appears.
Every subtopic, worked example, formula and trap in one printable document — answers shown, ready to share.
Subtopic notes
Industrial Gases and Paper-Making
6 PYQsWhat liquid nitrogen, argon, helium, oxygen and hydrogen sulphide are used for or known by, and the two chemicals behind paper: caustic soda to pulp, chlorine to bleach.
Fertilizers
3 PYQsWhat fertilizers supply (nitrogen, phosphorus, potassium), which compounds are nitrogen fertilizers, and how too much nitrate poisons groundwater.
Glass, Cement and Polymers
5 PYQsKinds of glass and why glass is called a supercooled liquid, why new concrete is kept wet, and thermoplastics against thermosetting plastics, with nylon's monomers.
Formula & revision sheet
0 formulas · 7 reference tables · 12 gotchas across all subtopics — the exam-eve cheat-sheet
Formula & revision sheet
0 formulas · 7 reference tables · 12 gotchas across all subtopics — the exam-eve cheat-sheet
Reference tables (2)
Uses of industrial gases5 rows
| Gas | Use or property |
|---|---|
| Liquid nitrogen | Storing blood, semen and organs at about −196 °CQ Asked in CDS 2020 (II) and 2022 (II). |
| Nitrogen gas | Fills food packets to prevent oxidation |
| Argon | Fills electric bulbsQ CDS 2024 (II): 'helium is commonly used in electric bulbs' was the incorrect statement. |
| Liquid oxygen | Burns fuel in rocket engines |
| Hydrogen sulphide | Smell of rotten eggsQ |
Watch out for (4)
- Bulbs use argon, not helium→ Uses of industrial gases
- Dry ice is not cold enough for tissue→ Uses of industrial gases
- Pulping uses an alkali, not an acid→ Chemicals in paper-making
- Chlorine bleaches; chloride does not→ Chemicals in paper-making
Reference tables (2)
What fertilizers supply4 rows
Nitrate pollution of groundwater3 rows
| Fertilizer | Moves into groundwater? | Harm |
|---|---|---|
| Nitrogen (as nitrate) | Yes — very soluble | Blue baby syndromeQ |
| Phosphate | Little — held by soil | Eutrophication in lakes via run-off |
| Potassium | Little — held by soil | Rarely a problem |
Watch out for (3)
- Nitrogen gas is not a fertilizer→ What fertilizers supply
- Iron is not an NPK nutrient→ What fertilizers supply
- Nitrate, not phosphate, reaches groundwater→ Nitrate pollution of groundwater
Reference tables (3)
Kinds of glass5 rows
| Glass | Special property | Used for |
|---|---|---|
| Soda (soft) glass | Cheap, melts easily | Windows, bottles |
| Pyrex (borosilicate) | Withstands heat | Cookware, lab flasks |
| Flint glass | High refractive index (lead oxide) | Optical instrumentsQ |
| Coloured glass | Metal oxides added | Decorative and signal glass |
| Water glass | Sodium silicate (soluble) | Adhesive, fireproofing |
Cement and the curing of concrete4 rows
| Material or step | What it is |
|---|---|
| Raw materials of cement | Limestone and clay |
| Gypsum in cement | Slows down setting |
| Curing concrete | Keeping it wet so water stays for hydrationQ |
| Concrete | Cement, sand, gravel and water |
Plastics and nylon4 rows
| Polymer | Monomer(s) | Kind |
|---|---|---|
| Nylon-6 | Caprolactam | Thermoplastic fibreQ CDS 2019 (I), HARD: nylon-6 is made from caprolactam alone. |
| Nylon-6,6 | Hexamethylenediamine + adipic acid | Thermoplastic fibre |
| Bakelite | Phenol + formaldehyde | Thermosetting |
| Polythene | Ethene | Thermoplastic |
Watch out for (5)
- Glass does not crystallise→ Kinds of glass
- Pyrex is for heat, flint for optics→ Kinds of glass
- Cement hardens by reacting, not by drying→ Cement and the curing of concrete
- Nylon-6 has one monomer, nylon-6,6 two→ Plastics and nylon
- Rigid when hot means thermosetting→ Plastics and nylon
PYQ weightage by concept
7 concepts · 14 PYQs — where the marks actually sit, so you know what to drill first
PYQ weightage by concept
7 concepts · 14 PYQs — where the marks actually sit, so you know what to drill first
| Concept | PYQs | Share |
|---|---|---|
| Uses of industrial gases | 4 | 29% |
| Chemicals in paper-making | 2 | 14% |
| Concept | PYQs | Share |
|---|---|---|
| What fertilizers supply | 2 | 14% |
| Nitrate pollution of groundwater | 1 | 7% |
| Concept | PYQs | Share |
|---|---|---|
| Kinds of glass | 2 | 14% |
| Plastics and nylon | 2 | 14% |
| Cement and the curing of concrete | 1 | 7% |
Test yourself on a real paper
Sit a past CDS paper, timed and marked the way the exam marks it. You see your score and every answer the moment you finish. Free to start.