https://exercises.lol/videos2026-09-05 https://exercises.lol/videos/a_level_biology2026-09-05 https://exercises.lol/videos/a_level_business2026-09-05 https://exercises.lol/videos/a_level_chemistry2026-09-05 https://exercises.lol/videos/a_level_physics2026-08-17 https://exercises.lol/videos/a_level_biology/cells2026-09-03https://exercises.lol/video-media/a_level_biology/cells/cells.thumb.jpg?v=1788444229How We Study CellsYou are built from about thirty trillion cells, yet you have never seen a single one. Cells are simply too small for the eye. A grain of sand is about a…https://exercises.lol/video-media/a_level_biology/cells/cells.enzh.mp4?v=17884442299852026-08-15yes https://exercises.lol/videos/a_level_biology/biological-molecules2026-09-03https://exercises.lol/video-media/a_level_biology/biological-molecules/biological-molecules.thumb.jpg?v=1788448752Biological MoleculesSuppose you have an unknown food sample. How do you tell what it is made of? Biology has a beautiful trick: add the right chemical, and the colour tells you…https://exercises.lol/video-media/a_level_biology/biological-molecules/biological-molecules.enzh.mp4?v=178844875211722026-08-15yes https://exercises.lol/videos/a_level_biology/enzymes2026-09-03https://exercises.lol/video-media/a_level_biology/enzymes/enzymes.thumb.jpg?v=1788441921EnzymesInside every cell, thousands of chemical reactions happen every second — far faster than they ever could on their own. The secret is a special kind of protein…https://exercises.lol/video-media/a_level_biology/enzymes/enzymes.enzh.mp4?v=17884419218312026-08-15yes https://exercises.lol/videos/a_level_biology/cell-membranes2026-09-05https://exercises.lol/video-media/a_level_biology/cell-membranes/cell-membranes.thumb.jpg?v=1788575944Cell MembranesEvery cell must keep the right things in and the wrong things out. That job falls to a single, astonishingly thin layer — the cell surface membrane, just two…https://exercises.lol/video-media/a_level_biology/cell-membranes/cell-membranes.enzh.mp4?v=17885759448432026-08-15yes https://exercises.lol/videos/a_level_biology/mitosis2026-09-03https://exercises.lol/video-media/a_level_biology/mitosis/mitosis.thumb.jpg?v=1788441201MitosisRight now, inside you, millions of cells are dividing. A cell grows, copies everything it contains, and splits into two — and the two daughter cells are not…https://exercises.lol/video-media/a_level_biology/mitosis/mitosis.enzh.mp4?v=17884412014392026-08-15yes https://exercises.lol/videos/a_level_biology/dna-protein-synthesis2026-09-05https://exercises.lol/video-media/a_level_biology/dna-protein-synthesis/dna-protein-synthesis.thumb.jpg?v=1788574722DNA & Protein SynthesisInside almost every one of your cells sits a molecule about two metres long, folded up so tightly you cannot see it. It is DNA, and it is written in an…https://exercises.lol/video-media/a_level_biology/dna-protein-synthesis/dna-protein-synthesis.enzh.mp4?v=17885747225732026-08-15yes https://exercises.lol/videos/a_level_biology/transport-in-plants2026-09-03https://exercises.lol/video-media/a_level_biology/transport-in-plants/transport-in-plants.thumb.jpg?v=1788449861Transport in PlantsA giant redwood lifts water more than a hundred metres into the air, every single day — and it has no heart, no muscle, no pump of any kind. So what does the…https://exercises.lol/video-media/a_level_biology/transport-in-plants/transport-in-plants.enzh.mp4?v=17884498615162026-08-15yes https://exercises.lol/videos/a_level_biology/circulatory-system2026-09-03https://exercises.lol/video-media/a_level_biology/circulatory-system/circulatory-system.thumb.jpg?v=1788446374The Circulatory SystemYour heart beats about a hundred thousand times a day, and it never gets a day off. But here is the clever part. It is not one loop. It is two. Blood leaves…https://exercises.lol/video-media/a_level_biology/circulatory-system/circulatory-system.enzh.mp4?v=17884463745562026-08-15yes https://exercises.lol/videos/a_level_biology/gas-exchange2026-09-03https://exercises.lol/video-media/a_level_biology/gas-exchange/gas-exchange.thumb.jpg?v=1788448068The Gas Exchange SystemSpread the inside of your lungs out flat and it would cover about seventy square metres — roughly half a tennis court. That whole area is folded up inside your…https://exercises.lol/video-media/a_level_biology/gas-exchange/gas-exchange.enzh.mp4?v=17884480684182026-08-15yes https://exercises.lol/videos/a_level_biology/infectious-disease2026-09-03https://exercises.lol/video-media/a_level_biology/infectious-disease/infectious-disease.thumb.jpg?v=1788447848Infectious DiseaseThe animal that kills the most people every year is not the shark or the snake. It is the mosquito. And the strange thing is that the mosquito itself does…https://exercises.lol/video-media/a_level_biology/infectious-disease/infectious-disease.enzh.mp4?v=17884478485082026-08-15yes https://exercises.lol/videos/a_level_biology/immunity2026-09-03https://exercises.lol/video-media/a_level_biology/immunity/immunity.thumb.jpg?v=1788439031ImmunityCatch measles once and you will almost certainly never catch it again. Your body has not become tougher, and the virus has not become weaker. What has changed…https://exercises.lol/video-media/a_level_biology/immunity/immunity.enzh.mp4?v=17884390315172026-08-15yes https://exercises.lol/videos/a_level_biology/respiration2026-09-03https://exercises.lol/video-media/a_level_biology/respiration/respiration.thumb.jpg?v=1788442235RespirationAt any moment your body holds only about fifty grams of ATP. Yet over a single day you will make and spend roughly your own body weight of it. The same…https://exercises.lol/video-media/a_level_biology/respiration/respiration.enzh.mp4?v=17884422355882026-08-15yes https://exercises.lol/videos/a_level_biology/photosynthesis2026-09-03https://exercises.lol/video-media/a_level_biology/photosynthesis/photosynthesis.thumb.jpg?v=1788446922PhotosynthesisHere is something strange about a tree. Almost none of it came out of the ground. The wood, the leaves, the fruit — nearly all of that mass was pulled out of…https://exercises.lol/video-media/a_level_biology/photosynthesis/photosynthesis.enzh.mp4?v=17884469225382026-08-15yes https://exercises.lol/videos/a_level_biology/homeostasis2026-09-03https://exercises.lol/video-media/a_level_biology/homeostasis/homeostasis.thumb.jpg?v=1788447255HomeostasisLook at a day's worth of blood sugar. Three big meals go in — and the level hardly stirs. It wanders a little, then comes straight back. That is not luck, and…https://exercises.lol/video-media/a_level_biology/homeostasis/homeostasis.enzh.mp4?v=17884472555812026-08-15yes https://exercises.lol/videos/a_level_biology/nerves-and-muscles2026-09-03https://exercises.lol/video-media/a_level_biology/nerves-and-muscles/nerves-and-muscles.thumb.jpg?v=1788449189Nerves and MusclesTouch something hot and your hand is already moving before you feel the pain. The signal never went to your brain to ask permission. It ran into the spinal…https://exercises.lol/video-media/a_level_biology/nerves-and-muscles/nerves-and-muscles.enzh.mp4?v=17884491895782026-08-15yes https://exercises.lol/videos/a_level_biology/genetics2026-09-03https://exercises.lol/video-media/a_level_biology/genetics/genetics.thumb.jpg?v=1788452186GeneticsYou have twenty three pairs of chromosomes. When a gamete is made, each pair lines up independently — either way round — so the number of different gametes you…https://exercises.lol/video-media/a_level_biology/genetics/genetics.enzh.mp4?v=17884521865752026-08-15yes https://exercises.lol/videos/a_level_biology/variation-and-evolution2026-09-03https://exercises.lol/video-media/a_level_biology/variation-and-evolution/variation-and-evolution.thumb.jpg?v=1788439353Variation and EvolutionIn the early eighteen hundreds, almost every peppered moth in England was pale and speckled, which hid it beautifully on lichen-covered bark. Then the…https://exercises.lol/video-media/a_level_biology/variation-and-evolution/variation-and-evolution.enzh.mp4?v=17884393535022026-08-15yes https://exercises.lol/videos/a_level_biology/biodiversity2026-09-03https://exercises.lol/video-media/a_level_biology/biodiversity/biodiversity.thumb.jpg?v=1788446648BiodiversityAbout one point seven million species have been described and given a name. The best estimates say there are probably eight to ten million out there. So most…https://exercises.lol/video-media/a_level_biology/biodiversity/biodiversity.enzh.mp4?v=17884466484782026-08-15yes https://exercises.lol/videos/a_level_biology/genetic-technology2026-09-03https://exercises.lol/video-media/a_level_biology/genetic-technology/genetic-technology.thumb.jpg?v=1788458510Genetic technologyTwo cotton plants. Same field, same insects, same week. The one on the left is barely touched. The one on the right has been eaten to bare stalks. The…https://exercises.lol/video-media/a_level_biology/genetic-technology/genetic-technology.enzh.mp4?v=17884585105102026-08-15yes https://exercises.lol/videos/a_level_business/business-basics2026-09-03https://exercises.lol/video-media/a_level_business/business-basics/business-basics.thumb.jpg?v=1788453166Business and its EnvironmentLook at a cup of coffee. The beans inside it cost a few cents. The milk, the cup, the lid — a few cents more. Yet people happily pay three dollars for it. So…https://exercises.lol/video-media/a_level_business/business-basics/business-basics.enzh.mp4?v=178845316613032026-08-15yes https://exercises.lol/videos/a_level_business/human-resources2026-09-05https://exercises.lol/video-media/a_level_business/human-resources/human-resources.thumb.jpg?v=1788574443Human Resource ManagementTwo factories. Same machines, same materials, same hours. One makes twice as much as the other. The difference is not the equipment — it is the people. Labour…https://exercises.lol/video-media/a_level_business/human-resources/human-resources.enzh.mp4?v=17885744436242026-08-15yes https://exercises.lol/videos/a_level_business/marketing2026-09-03https://exercises.lol/video-media/a_level_business/marketing/marketing.thumb.jpg?v=1788453153MarketingTwo shops sell the same coffee at the same price. One is always busy; the other sits empty. Nothing about the product explains it. The difference is marketing…https://exercises.lol/video-media/a_level_business/marketing/marketing.enzh.mp4?v=17884531539142026-08-15yes https://exercises.lol/videos/a_level_business/operations2026-09-05https://exercises.lol/video-media/a_level_business/operations/operations.thumb.jpg?v=1788572095Operations ManagementA car factory takes in steel, plastic, glass, electricity and hours of work. Out the other end comes a car worth far more than everything that went into it.…https://exercises.lol/video-media/a_level_business/operations/operations.enzh.mp4?v=17885720954862026-08-15yes https://exercises.lol/videos/a_level_business/finance2026-09-03https://exercises.lol/video-media/a_level_business/finance/finance.thumb.jpg?v=1788447587Finance and AccountingA business can be profitable and still die. Here is how. You sell a hundred thousand pounds of goods on credit in March. The profit looks excellent. But the…https://exercises.lol/video-media/a_level_business/finance/finance.enzh.mp4?v=17884475879502026-08-15yes https://exercises.lol/videos/a_level_business/external-influences2026-09-05https://exercises.lol/video-media/a_level_business/external-influences/external-influences.thumb.jpg?v=1788573541External Influences and StrategyIn two thousand and eight, thousands of well-run firms went under. Their products were good. Their staff were good. Their costs were under control. What killed…https://exercises.lol/video-media/a_level_business/external-influences/external-influences.enzh.mp4?v=17885735414892026-08-15yes https://exercises.lol/videos/a_level_business/organisation2026-09-03https://exercises.lol/video-media/a_level_business/organisation/organisation.thumb.jpg?v=1788452744Organisation, Leadership and HRMA director says: cut costs by five percent this quarter. It passes to a senior manager, then a department head, then a supervisor, then the team. By the time…https://exercises.lol/video-media/a_level_business/organisation/organisation.enzh.mp4?v=17884527445142026-08-15yes https://exercises.lol/videos/a_level_business/marketing-a-level2026-09-03https://exercises.lol/video-media/a_level_business/marketing-a-level/marketing-a-level.thumb.jpg?v=1788453935Marketing (A Level)Every shop is running on numbers. How much to order. What price to charge. Which new product to try. Get those wrong, and food goes in the bin, or the shelves…https://exercises.lol/video-media/a_level_business/marketing-a-level/marketing-a-level.enzh.mp4?v=17884539354852026-08-15yes https://exercises.lol/videos/a_level_business/operations-management-a-level2026-09-05https://exercises.lol/video-media/a_level_business/operations-management-a-level/operations-management-a-level.thumb.jpg?v=1788575638Operations management (A Level)A company promised its new factory in a hundred and fifteen weeks. It opened thirty weeks late, at a huge cost in wages and rent. One task slipped in the…https://exercises.lol/video-media/a_level_business/operations-management-a-level/operations-management-a-level.enzh.mp4?v=17885756384652026-08-15yes https://exercises.lol/videos/a_level_business/finance-and-accounting-a-level2026-09-03https://exercises.lol/video-media/a_level_business/finance-and-accounting-a-level/finance-and-accounting-a-level.thumb.jpg?v=1788441662Finance and accounting (A Level)Two shops on the same street. Both sold five hundred thousand pounds of goods last year, and they look identical. But one is about to open three new branches…https://exercises.lol/video-media/a_level_business/finance-and-accounting-a-level/finance-and-accounting-a-level.enzh.mp4?v=17884416625752026-08-15yes https://exercises.lol/videos/a_level_chemistry/atomic-structure2026-09-05https://exercises.lol/video-media/a_level_chemistry/atomic-structure/atomic-structure.thumb.jpg?v=1788574736Atomic StructureNo 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…https://exercises.lol/video-media/a_level_chemistry/atomic-structure/atomic-structure.enzh.mp4?v=178857473613852026-08-15yes https://exercises.lol/videos/a_level_chemistry/moles-stoichiometry2026-09-05https://exercises.lol/video-media/a_level_chemistry/moles-stoichiometry/moles-stoichiometry.thumb.jpg?v=1788572316Atoms, Molecules & StoichiometryHere 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…https://exercises.lol/video-media/a_level_chemistry/moles-stoichiometry/moles-stoichiometry.enzh.mp4?v=178857231611412026-08-15yes https://exercises.lol/videos/a_level_chemistry/chemical-bonding2026-09-03https://exercises.lol/video-media/a_level_chemistry/chemical-bonding/chemical-bonding.thumb.jpg?v=1788449055Chemical BondingTwo 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…https://exercises.lol/video-media/a_level_chemistry/chemical-bonding/chemical-bonding.enzh.mp4?v=17884490559052026-08-15yes https://exercises.lol/videos/a_level_chemistry/energetics2026-09-05https://exercises.lol/video-media/a_level_chemistry/energetics/energetics.thumb.jpg?v=1788571330Chemical EnergeticsA 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…https://exercises.lol/video-media/a_level_chemistry/energetics/energetics.enzh.mp4?v=17885713305012026-08-15yes https://exercises.lol/videos/a_level_chemistry/equilibria2026-09-05https://exercises.lol/video-media/a_level_chemistry/equilibria/equilibria.thumb.jpg?v=1788575113EquilibriaSome 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…https://exercises.lol/video-media/a_level_chemistry/equilibria/equilibria.enzh.mp4?v=17885751136122026-08-15yes https://exercises.lol/videos/a_level_chemistry/reaction-kinetics2026-09-03https://exercises.lol/video-media/a_level_chemistry/reaction-kinetics/reaction-kinetics.thumb.jpg?v=1788437950Reaction kineticsIron 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…https://exercises.lol/video-media/a_level_chemistry/reaction-kinetics/reaction-kinetics.enzh.mp4?v=17884379504322026-08-15yes https://exercises.lol/videos/a_level_chemistry/chemical-periodicity2026-09-05https://exercises.lol/video-media/a_level_chemistry/chemical-periodicity/chemical-periodicity.thumb.jpg?v=1788571736The Periodic Table: chemical periodicitySodium 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…https://exercises.lol/video-media/a_level_chemistry/chemical-periodicity/chemical-periodicity.enzh.mp4?v=17885717365232026-08-15yes https://exercises.lol/videos/a_level_chemistry/group-22026-09-05https://exercises.lol/video-media/a_level_chemistry/group-2/group-2.thumb.jpg?v=1788572768Group 2Before 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…https://exercises.lol/video-media/a_level_chemistry/group-2/group-2.enzh.mp4?v=17885727684812026-08-15yes https://exercises.lol/videos/a_level_chemistry/group-172026-09-05https://exercises.lol/video-media/a_level_chemistry/group-17/group-17.thumb.jpg?v=1788570087Group 17Here 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…https://exercises.lol/video-media/a_level_chemistry/group-17/group-17.enzh.mp4?v=17885700874472026-08-15yes https://exercises.lol/videos/a_level_chemistry/nitrogen-sulfur2026-09-03https://exercises.lol/video-media/a_level_chemistry/nitrogen-sulfur/nitrogen-sulfur.thumb.jpg?v=1788449399Nitrogen and sulfurTake 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…https://exercises.lol/video-media/a_level_chemistry/nitrogen-sulfur/nitrogen-sulfur.enzh.mp4?v=17884493994602026-08-15yes https://exercises.lol/videos/a_level_chemistry/organic-intro2026-09-03https://exercises.lol/video-media/a_level_chemistry/organic-intro/organic-intro.thumb.jpg?v=1788447320An introduction to AS Level organic chemistryChemists have found more than ten million hydrocarbons and carbon compounds. Ten million. So how can anyone learn organic chemistry? Because almost all of them…https://exercises.lol/video-media/a_level_chemistry/organic-intro/organic-intro.enzh.mp4?v=17884473205352026-08-15yes https://exercises.lol/videos/a_level_chemistry/hydrocarbons2026-09-05https://exercises.lol/video-media/a_level_chemistry/hydrocarbons/hydrocarbons.thumb.jpg?v=1788573562HydrocarbonsTwo 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…https://exercises.lol/video-media/a_level_chemistry/hydrocarbons/hydrocarbons.enzh.mp4?v=17885735625932026-08-15yes https://exercises.lol/videos/a_level_chemistry/halogen-compounds2026-09-05https://exercises.lol/video-media/a_level_chemistry/halogen-compounds/halogen-compounds.thumb.jpg?v=1788575859Halogen compoundsPress 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…https://exercises.lol/video-media/a_level_chemistry/halogen-compounds/halogen-compounds.enzh.mp4?v=17885758594512026-08-15yes https://exercises.lol/videos/a_level_chemistry/hydroxy-compounds2026-09-05https://exercises.lol/video-media/a_level_chemistry/hydroxy-compounds/hydroxy-compounds.thumb.jpg?v=1788574103Hydroxy compoundsSqueeze 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…https://exercises.lol/video-media/a_level_chemistry/hydroxy-compounds/hydroxy-compounds.enzh.mp4?v=17885741034992026-08-15yes https://exercises.lol/videos/a_level_chemistry/carbonyl-compounds2026-09-05https://exercises.lol/video-media/a_level_chemistry/carbonyl-compounds/carbonyl-compounds.thumb.jpg?v=1788575797Carbonyl compoundsOpen 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…https://exercises.lol/video-media/a_level_chemistry/carbonyl-compounds/carbonyl-compounds.enzh.mp4?v=17885757974822026-08-15yes https://exercises.lol/videos/a_level_chemistry/carboxylic-acids2026-09-03https://exercises.lol/video-media/a_level_chemistry/carboxylic-acids/carboxylic-acids.thumb.jpg?v=1788449324Carboxylic acids and derivativesOpen 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…https://exercises.lol/video-media/a_level_chemistry/carboxylic-acids/carboxylic-acids.enzh.mp4?v=17884493244822026-08-15yes https://exercises.lol/videos/a_level_chemistry/nitrogen-compounds2026-09-03https://exercises.lol/video-media/a_level_chemistry/nitrogen-compounds/nitrogen-compounds.thumb.jpg?v=1788447507Nitrogen compoundsLook 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…https://exercises.lol/video-media/a_level_chemistry/nitrogen-compounds/nitrogen-compounds.enzh.mp4?v=17884475074652026-08-15yes https://exercises.lol/videos/a_level_chemistry/polymerisation2026-09-05https://exercises.lol/video-media/a_level_chemistry/polymerisation/polymerisation.thumb.jpg?v=1788575803PolymerisationLook 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…https://exercises.lol/video-media/a_level_chemistry/polymerisation/polymerisation.enzh.mp4?v=17885758034432026-08-15yes https://exercises.lol/videos/a_level_chemistry/organic-synthesis2026-09-05https://exercises.lol/video-media/a_level_chemistry/organic-synthesis/organic-synthesis.thumb.jpg?v=1788575343Organic synthesisLook 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…https://exercises.lol/video-media/a_level_chemistry/organic-synthesis/organic-synthesis.enzh.mp4?v=17885753434802026-08-15yes https://exercises.lol/videos/a_level_chemistry/analytical-techniques-as2026-09-03https://exercises.lol/video-media/a_level_chemistry/analytical-techniques-as/analytical-techniques-as.thumb.jpg?v=1788449194Analytical 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…https://exercises.lol/video-media/a_level_chemistry/analytical-techniques-as/analytical-techniques-as.enzh.mp4?v=17884491945242026-08-15yes https://exercises.lol/videos/a_level_chemistry/energetics-a22026-09-05https://exercises.lol/video-media/a_level_chemistry/energetics-a2/energetics-a2.thumb.jpg?v=1788570662Chemical 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…https://exercises.lol/video-media/a_level_chemistry/energetics-a2/energetics-a2.enzh.mp4?v=17885706624822026-08-15yes https://exercises.lol/videos/a_level_chemistry/electrochemistry-a22026-09-05https://exercises.lol/video-media/a_level_chemistry/electrochemistry-a2/electrochemistry-a2.thumb.jpg?v=1788571729Electrochemistry (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…https://exercises.lol/video-media/a_level_chemistry/electrochemistry-a2/electrochemistry-a2.enzh.mp4?v=17885717294732026-08-15yes https://exercises.lol/videos/a_level_chemistry/equilibria-a22026-09-05https://exercises.lol/video-media/a_level_chemistry/equilibria-a2/equilibria-a2.thumb.jpg?v=1788574945Equilibria (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…https://exercises.lol/video-media/a_level_chemistry/equilibria-a2/equilibria-a2.enzh.mp4?v=17885749454752026-08-15yes https://exercises.lol/videos/a_level_chemistry/kinetics-a22026-09-03https://exercises.lol/video-media/a_level_chemistry/kinetics-a2/kinetics-a2.thumb.jpg?v=1788447027Reaction 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…https://exercises.lol/video-media/a_level_chemistry/kinetics-a2/kinetics-a2.enzh.mp4?v=17884470274802026-08-15yes https://exercises.lol/videos/a_level_chemistry/group-2-a22026-09-03https://exercises.lol/video-media/a_level_chemistry/group-2-a2/group-2-a2.thumb.jpg?v=1788445927Group 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.…https://exercises.lol/video-media/a_level_chemistry/group-2-a2/group-2-a2.enzh.mp4?v=17884459274862026-08-15yes https://exercises.lol/videos/a_level_chemistry/organic-intro-a22026-09-05https://exercises.lol/video-media/a_level_chemistry/organic-intro-a2/organic-intro-a2.thumb.jpg?v=1788575995An introduction to A Level organic chemistryTwo 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…https://exercises.lol/video-media/a_level_chemistry/organic-intro-a2/organic-intro-a2.enzh.mp4?v=17885759955082026-08-15yes https://exercises.lol/videos/a_level_chemistry/arenes2026-09-03https://exercises.lol/video-media/a_level_chemistry/arenes/arenes.thumb.jpg?v=1788447382Hydrocarbons (A2): arenesOrange 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…https://exercises.lol/video-media/a_level_chemistry/arenes/arenes.enzh.mp4?v=17884473824622026-08-15yes https://exercises.lol/videos/a_level_chemistry/halogen-a22026-09-05https://exercises.lol/video-media/a_level_chemistry/halogen-a2/halogen-a2.thumb.jpg?v=1788575490Halogen 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…https://exercises.lol/video-media/a_level_chemistry/halogen-a2/halogen-a2.enzh.mp4?v=17885754904762026-08-15yes https://exercises.lol/videos/a_level_chemistry/phenol2026-09-05https://exercises.lol/video-media/a_level_chemistry/phenol/phenol.thumb.jpg?v=1788575870Hydroxy compounds (A2): phenolIn the eighteen sixties, surgery was terrifying. The cutting could be survived; the infection that followed often could not. After an amputation, almost half…https://exercises.lol/video-media/a_level_chemistry/phenol/phenol.enzh.mp4?v=17885758705182026-08-15yes https://exercises.lol/videos/a_level_chemistry/carboxylic-a22026-09-05https://exercises.lol/video-media/a_level_chemistry/carboxylic-a2/carboxylic-a2.thumb.jpg?v=1788575498Carboxylic 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…https://exercises.lol/video-media/a_level_chemistry/carboxylic-a2/carboxylic-a2.enzh.mp4?v=17885754984872026-08-15yes https://exercises.lol/videos/a_level_chemistry/nitrogen-organic2026-09-05https://exercises.lol/video-media/a_level_chemistry/nitrogen-organic/nitrogen-organic.thumb.jpg?v=1788571463Nitrogen compoundsLook 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…https://exercises.lol/video-media/a_level_chemistry/nitrogen-organic/nitrogen-organic.enzh.mp4?v=17885714634692026-08-15yes https://exercises.lol/videos/a_level_chemistry/polymerisation-a22026-09-05https://exercises.lol/video-media/a_level_chemistry/polymerisation-a2/polymerisation-a2.thumb.jpg?v=1788571409Polymerisation (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…https://exercises.lol/video-media/a_level_chemistry/polymerisation-a2/polymerisation-a2.enzh.mp4?v=17885714094782026-08-15yes https://exercises.lol/videos/a_level_chemistry/nmr-spectroscopy2026-09-05https://exercises.lol/video-media/a_level_chemistry/nmr-spectroscopy/nmr-spectroscopy.thumb.jpg?v=1788570651Analytical techniques (A2): NMRHere 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…https://exercises.lol/video-media/a_level_chemistry/nmr-spectroscopy/nmr-spectroscopy.enzh.mp4?v=17885706514862026-08-15yes https://exercises.lol/videos/a_level_physics/oscillations2026-08-17https://exercises.lol/video-media/a_level_physics/oscillations/oscillations.thumb.jpg?v=1786969185Oscillations & Simple Harmonic MotionIn 1940, a brand-new bridge opened across the Tacoma Narrows — long, elegant, and, as it turned out, dangerous. Within months, an ordinary wind set it heaving…https://exercises.lol/video-media/a_level_physics/oscillations/oscillations.enzh.mp4?v=17869691859122026-08-15yes