A-Level Chemistry

23:05 Topic 1 Atomic Structure No one has ever seen inside an atom. It is far too small — a single atom is about a million times thinner than a human hair. And yet we know exactly how its… 19:02 Topic 2 Atoms, Molecules & Stoichiometry Here is a problem. A single teaspoon of water holds about two hundred thousand billion billion molecules. You could never count them — not in a lifetime, not… 15:06 Topic 3 Chemical Bonding Two molecules, almost the same size. Water, and hydrogen sulfide. Sulfur sits directly below oxygen in the Periodic Table, so you would expect the two to… 7:31 Topic 4 States of Matter Diamond melts at three thousand five hundred and fifty degrees Celsius. Iodine melts at one hundred and fourteen. Both are made only of non-metal atoms, and in… 8:21 Topic 5 Chemical Energetics A Bunsen burner gets hot enough to soften glass. An instant cold pack, squeezed once, drops close to freezing. Both are just chemical reactions — one in a… 6:34 Topic 6 Electrochemistry & Redox Two pieces of iron. One is quietly rusting on a fence. The other sits inside a battery, pushing electrons through your phone. They look like completely… 10:12 Topic 7 Equilibria Some reversible reactions never finish. You mix the reactants, the colour changes, and then everything just stops — halfway. Leave it for a week and it looks… 7:13 Topic 8 Reaction kinetics Iron left outside takes years to rust away. Strike a match, and almost the same chemistry — oxygen attacking a fuel — is over in less than a second. Same… 8:43 Topic 9 The Periodic Table: chemical periodicity Sodium and argon sit in the same row of the Periodic Table, with only six elements between them. Drop sodium into cold water and it melts into a shining ball… 8:01 Topic 10 Group 2 Before a stomach X-ray, the patient is asked to drink a thick white liquid. It is full of barium — and barium ions are poisonous. Swallow a soluble barium salt… 7:28 Topic 11 Group 17 Here are three colourless solutions. They look exactly the same. One is a chloride, one is a bromide, one is an iodide — but you cannot tell which is which by… 7:40 Topic 12 Nitrogen and sulfur Take a breath. Nearly four fifths of what just went into your lungs was nitrogen — and it came straight back out again, completely unchanged. Nitrogen is… 8:56 Topic 13 An introduction to AS Level organic chemistry Chemists have found more than ten million hydrocarbons and carbon compounds. Ten million. So how can anyone learn organic chemistry? Because almost all of them… 9:54 Topic 14 Hydrocarbons Two clear liquids, both nothing but carbon and hydrogen. And two test tubes of orange bromine water. Shake the first liquid into one tube, the second into the… 7:31 Topic 15 Halogen compounds Press the button on a can of freezer spray, and your skin goes numb with cold. Inside is a halogenoalkane: an alkane with a halogen atom in place of one… 8:20 Topic 16 Hydroxy compounds Squeeze hand sanitiser onto your hands. It feels cold, and then it is gone. That is ethanol — the alcohol that kills the microbes. Ethanol is only a short… 8:03 Topic 17 Carbonyl compounds Open a bottle of nail polish remover, and that sharp smell is propanone. Your own body makes a little of it every day. All of that comes from one small group… 8:02 Topic 18 Carboxylic acids and derivatives Open a bottle of vinegar and you know it at once. That sharp smell is ethanoic acid, and vinegar is only a weak solution of it in water. Pour a little onto… 7:46 Topic 19 Nitrogen compounds Look at the thread in a jacket, a rope, a pair of stockings: nylon. It is built from two kinds of molecule, joined again and again — one with a nitrogen group… 7:24 Topic 20 Polymerisation Look around you. A drinks cup. A shopping bag. A plastic wrapper. All three are made of the same kind of thing: one enormous molecule, a chain that is tens of… 8:01 Topic 21 Organic synthesis Look at almost any medicine. It is a complicated molecule, and it began as something simple — often a small molecule from crude oil. No single reaction turns… 8:45 Topic 22 Analytical techniques (AS) You have just made a new compound. It is a clear liquid in a flask, with no label, and you cannot see a single molecule. How do you prove what it is? You ask… 8:02 Topic 23 Chemical energetics (A2) Sodium is a soft metal that burns in air. Chlorine is a choking, poisonous gas. Put them together and you get table salt. Making one mole of it gives out a… 7:53 Topic 24 Electrochemistry (A2) Two things in your pocket run on the same chemistry. A battery: a reaction that wants to happen pushes electrons through a wire. And the charger: we push those… 7:56 Topic 25 Equilibria (A2) Your blood is held at pH seven point four. Move it a few tenths either way and you are in hospital. Yet all day, acid pours in — from your food, and from your… 8:01 Topic 26 Reaction kinetics (A2) Here is a real reaction: hydrogen peroxide reacting with iodide ions in acid. Look at the balanced equation. It uses two iodide ions and two hydrogen ions… 8:06 Topic 27 Group 2 (A2) Here is a puzzle. Go down Group 2, from magnesium to barium, and the hydroxides get more soluble. Go down the same group, and the sulfates get less soluble.… 8:24 Topic 28 Chemistry of transition elements Look at these six test tubes: pink, orange, yellow, green, blue, violet. Every one holds a d-block metal in water, and every metal comes from the same short… 8:28 Topic 29 An introduction to A Level organic chemistry Two molecules. Same atoms, same bonds. The only difference: one is the mirror image of the other, like your left hand and your right hand. And yet one of them… 7:42 Topic 30 Hydrocarbons (A2): arenes Orange bromine water is the classic test for a double bond. Shake it with an alkene, and the orange colour vanishes at once. Now shake the very same bromine… 7:56 Topic 31 Halogen compounds (A2) A farmer sprays a field. Many of the pesticides and weedkillers in that tank are halogenoarenes: a chlorine atom bonded straight onto a benzene ring. Now look… 8:38 Topic 32 Hydroxy compounds (A2): phenol In the eighteen sixties, surgery was terrifying. The cutting could be survived; the infection that followed often could not. After an amputation, almost half… 8:08 Topic 33 Carboxylic acids and derivatives (A2) Open a medicine cabinet and pick up a packet of aspirin. That tablet is an ester. At AS you met one small group: the carboxyl group. At A2 it becomes three new… 7:49 Topic 34 Nitrogen compounds Look at three very different things. A sweet, dyed bright orange. A painkiller tablet. And the protein in your muscles. They share almost nothing — except one… 7:58 Topic 35 Polymerisation (A2) Look at three very different things. A nylon rope. A plastic drinks bottle. The protein in your own hair. They seem to have nothing in common. Yet all three… 7:52 Topic 36 Organic synthesis (A2) Three very different things: a bright orange dye, a painkiller, and a tough plastic. All three begin as the same colourless liquid — benzene. But no single… 8:06 Topic 37 Analytical techniques (A2): NMR Here are seven different molecules. Every one has five carbons, ten hydrogens and one oxygen, and every one contains a carbonyl group. Weigh them in a mass…