See chemistry in motion

Backside attack of OH⁻ on 2-bromobutane. Watch the Walden inversion in real-time 3D with transition state pause.

Two-step ionisation via a carbocation intermediate — and why SN1 gives racemisation rather than inversion.

Attack of CN⁻ on a carbonyl group — how the nucleophile targets the electrophilic C=O carbon.

Addition of Br₂ to ethene — π bond attack, carbocation intermediate, and 1,2-dibromoethane product.

Addition of HBr to propene — why the H adds to the CH₂ carbon, and how the more stable 2° carbocation decides the major product.

Chlorination of benzene — how Cl⁺ attacks the aromatic ring and aromaticity is restored.

Plan 3-step organic syntheses. Drag reagents and conditions onto each arrow, watch intermediates appear, and reach the target product. 17 questions covering aliphatic and aromatic routes.

Pick chemical tests that give different observations for the compounds shown. 20 pair questions and 10 advanced sets of 3 or 4 compounds. Drag reagent, condition, and observation chips, then submit.

Explore all 13 molecular shapes across 2–6 electron pairs. Interactive 3D rotation with lone pair visualisation.

Build up 24 dot-and-cross diagrams step by step, from ammonia to sulfate. See exactly how dative bonds form and why, with narrated animations.

Explore Boyle's and Gay-Lussac's Laws interactively. Watch particles collide as you adjust pressure, volume and temperature.

Explore all 118 elements with click-for-details. Toggle heatmaps for electronegativity, atomic radius, 1st ionisation energy and melting point — or filter to just the H2 syllabus elements.

Build energy cycles with drag-and-drop. Covers formation, combustion, bond-energy and Born-Haber. Compare clockwise vs anticlockwise paths to solve for ΔH.

Visualise how molecular speeds are distributed in a gas. Adjust temperature and see the curve shift — and where activation energy fits in.

Compare a Daniell cell with electrolysis side-by-side. Switch between Cu purification, molten NaCl and brine to see how electrons, ions and electrode polarity flip.

Watch the N₂O₄ ⇌ 2NO₂ equilibrium shift as you heat, compress or inject gas. The brown colour deepens and fades in real time as the position of equilibrium re-establishes.

A 3D polarimeter walkthrough: unpolarised light is filtered to a single plane, an optically active solution rotates that plane, and you turn the analyser to measure the optical rotation.

Mix the 2s and 2p orbitals into sp³, sp² and sp hybrids, pull each hybrid apart to see its shape, then bond two carbons to build the σ and π bonds of C=C and C≡C.

Build any Period-4 atom or ion by dragging electrons into 4s and 3d. See why 4s fills before 3d yet is removed first, and get the Cr and Cu exceptions right.