Simulate the AP Chemistry exam end-to-end: Section I (60 MCQ, 90 min) then Section II (3 long + 4 short FRQ, 105 min) with countdown timers and a 1–5 band score.

Multiple-choice exam: pick units and count, then work through questions with eliminate-option tools, instant feedback, and explanations.

Choose units, type, and count, then work through free-response questions with typeable answers, a timer, and rubric self-scoring.

Quizlet-style vocabulary trainer: flip cards, run Learn mode with typed recall, or race the clock in Match mode to pair terms with definitions.

Questions you got wrong are automatically tracked here. Filter by unit, practice MCQs and FRQs you missed, and master them to clear your list.

Type any formula, then enter one quantity and watch particles, mass, and gas volume solve through the mole hub. Every conversion is a factor-label step with units cancelling, and each rail lights the divide or multiply lane your own arithmetic travels.

Real mass spectra for all 84 elements that occur with a natural isotopic composition, drawn from NIST data. Point at a peak to read its m/z and abundance, and switch the axis between base-peak and percent scaling to see the weighted average atomic mass build up term by term.

Eight pure substances drawn to real bond angles and ionic radii, five as discrete molecules and three as lattices with one formula unit outlined. Count the atoms in the box and the empirical formula falls out; change the sample size and the percent by mass refuses to move.

Weigh out a two-component mixture such as NaCl and KCl and watch the particle box refill by mole ratio. Switch to elemental analysis to sort every atom by element, then read one measured percent back into the mass of each component.

Orbital boxes stacked shell by shell, with the Aufbau path threaded through them. Step the charge to build a common ion and the electrons that leave go hollow, while the shell model tracks r and shielding.

A spectrograph plate and matching intensity trace for 9 elements. Click any line to get λ, ν and the photon energy in joules, worked step by step from c = λν and E = hν.

A log-scale spectrum on the exam's own 1000 to 0.1 MJ/mol axis for H through Ca. Hover a peak to link it to its subshell, shell and Coulombic pull, or overlay the neighbouring element.

All 118 elements heat-mapped by atomic radius, ionization energy, electronegativity, and more. Click any element to compare it against its period or group on a live chart.

A mini periodic table sets the valence count for a metal and a nonmetal. Watch electrons transfer atom by atom, then read the charge balance that fixes the neutral formula.

Pick two elements from a live electronegativity map and watch a real electron density map redraw itself. Covalent, ionic, and metallic bonding, named by the metal and nonmetal rule rather than a ΔEN cutoff.

Push two atoms together and read the equilibrium bond length and bond energy off the curve. Isolate core size from bond order, then switch to cations and anions and rank them by Coulombic force.

Rotate a 3D array of ions drawn at real ionic radii for 9 compounds. Compare charge and size through Coulomb's law, then shove one layer sideways until like charges meet and the crystal cleaves.

Positive metal cores in a live sea of delocalized valence electrons. Apply a voltage, heat one edge, shear the lattice, or alloy it, and see why metals conduct, bend, and stiffen with carbon.

Click any atom on 13 Lewis diagrams to see FC = V − L − ½B worked out term by term, then step between the competing structures of BF₃, SO₂ and sulfate to see which one formal charge picks

Work through all three parts of topic 2.6 on 12 species: equivalent contributors and their hybrid, nonequivalent diagrams that formal charge has to choose between, and the odd-electron cases where the Lewis model runs out

Rotate 23 real molecules built from experimental bond angles and bond lengths. Toggle lone pair lobes, angle arcs, and the net dipole to see why shape decides polarity.

Rotate 10 real molecules and watch σ and π orbitals overlap side by side. Count σ bonds plus lone pairs to get the steric number, then read off sp, sp², or sp³ and the ideal angle.

Watch 14 substances at real molecular geometry condense or disperse as you drag the temperature. Compare two side by side, then read the same set as boiling point and solubility charts.

Eight real lattices drawn at true particle radii, from NaCl to diamond. Heat a sample past its melting point or shear one layer across the next to see why ionic solids shatter, metals bend, and graphite slides.

Drag a state point across a P-T map of water or CO₂ and watch the particulate view redraw to scale. Compare arrangement, motion, and the molar volume of solid, liquid, and gas

Load a piston cylinder or lock its volume, change one variable and see which one PV = nRT forces to move. Switch to a three-gas mixture and read partial pressure straight off mole fraction

A particulate model sits above the live curve on fixed axes, so heating visibly flattens the peak without changing the area. Pin a second curve to compare, then switch the axis to kinetic energy and watch every gas land on one curve.

Two sealed chambers, one gas each, both venting to vacuum at one temperature. Pick the two gases and watch which empties first, with the speed ratio worked out on screen from KE = ½mv²

Two cylinders hold one mole each at one temperature: the left one obeys PV = nRT, the right one is a real gas. Compress them together and watch the pistons come apart, with the gap split into the two causes the exam names — the space the molecules occupy and the pull between them.

A graduated cylinder and a volumetric flask drawn to one real scale. Solve M₁V₁ = M₂V₂ for any unknown and watch a fixed amount of solute spread through more solution, with every answer rounded to the significant figures the inputs allow.

Two beakers of equal volume drawn particle by particle. Set the solute in each and compare the count of every component, watch a crystal break up at its surface, then zoom in on the water molecules turning to face each ion.

Develop a spinach extract by paper, thin-layer, or column chromatography. Swap the stationary and mobile phases and watch the elution order reverse, then read relative polarities off the chromatogram.

A live particulate model of four solutes in water and in hexane, with the vial you would actually see beside it. Pick any of the eight pairs and read the measured solubility, from miscible down to 0.03 g per 100 mL.

A wavelength-scaled EM spectrum paired with the energy-level ladder behind each transition. Send a photon through HCl and see why electronic gaps need UV/vis, vibrational need IR, and rotational need microwaves.

Fire a photon at a 3-level atom — it absorbs only when hν = ΔE; mismatches pass through. Switch to emit and drop the electron to send the matching photon out.

A spectrophotometer bench where the beam takes the colour of the wavelength you select. Tune λ, path length and concentration to see A = εbc build the calibration line whose slope is εb.

Predict physical or chemical, then run 12 bench trials and judge them against the four kinds of evidence. Look-alike cases show why bubbles and colour are never proof on their own.

Step through molecular, complete ionic, and net ionic equations for 8 reactions. Toggle spectator ion crossouts and see which solubility rules apply at each stage.

Pick a balanced equation and see the matching particulate diagram. Build it molecule by molecule with live coefficient narration, or view the full representation.

Select from 8 scenarios to see before/after molecular views of physical vs. chemical changes. Bond-breaking flashes red in the before panel, bond-forming flashes green.

Slide reactant mole amounts and watch molecules flash and react. The limiting reagent is identified automatically, with theoretical yield and excess calculated live.

Adjust theoretical and actual yield sliders and watch two flasks fill to match. A color-coded quality badge rates the result from Excellent to Poor across 5 real reactions.

Browse 13 examples across all 5 reaction types with 3D molecule diagrams. Each entry shows the balanced equation, identification tips, and common mistakes to avoid.

Build two solutions from 13 cations and 11 anions, then pour A into B. Predict the outcome first, then check the molecular, complete ionic, and net ionic equations against the rule that decided it.

Before and after compound cards show H⁺ transferring from acid to base for 9 reactions. Conjugate pairs are labeled below, with pH outcome explained by reactant strength.

Electrons flow along a curved arrow from reducing to oxidizing agent. Oxidation numbers, half-reactions, and the OIL RIG mnemonic update for each of 5 reactions.

Pick from 5 reactions and watch particles merge on collision. Tune concentration, temperature, surface area, and catalyst to see rate = k[A]ᵐ[B]ⁿ update live in M/s.

Select two experiments to derive the order for each reactant. Bar charts show rate and concentration ratios before the full rate law and k are assembled.

Three graphs plot [A] vs t, ln[A] vs t, and 1/[A] vs t simultaneously. The straightest line reveals reaction order, confirmed by live R² values for each plot.

Drag a time probe along a first-order decay curve to read percent remaining. A shrinking atom grid and half-life table reinforce the concept across 5 real isotope presets.

Particles collide across uni-, bi-, and rare termolecular steps. Elementary rate laws come from coefficients, while overall exponents must be measured.

Molecules collide in a live sim — bad orientation sparks orange, successful reactions glow green. Forward and reverse rates trend on a live graph as temperature changes.

Seven measured reactions plot as a live profile with ball-and-stick molecules at each stage. Drag the ‡ marker or the product level, then add a real catalyst and watch its two-step pathway appear.

Step through 4 multi-step mechanisms with species pills and an energy profile. Intermediates and catalysts are identified, and the rate law is derived from the slow step.

A slow-first mechanism throttles particles through a bottleneck up top while a rate-vs-[X] curve responds live. Sliders reveal orders 0, 1, and 2 straight from the slow step.

Pick a mechanism whose slow step is not first and watch the intermediate get substituted out via K₁. Each of 5 reactions derives its observed rate law in 4 lines.

Watch catalysts bind reactants in Step 1 and release products in Step 2 across 3 cycles. Counters prove Δ[catalyst] = 0 while intermediate cancels overall.

A glowing ball traces exothermic and endothermic energy profiles for 6 real reactions. Surroundings particles speed up or slow down to show heat flow direction.

A two-level energy diagram redraws for 8 physical and chemical processes as the reactant and product bars snap to their kJ/mol levels. Zoom or reverse to watch ΔH flip sign.

Coffee cup and bomb calorimeters with live temp graphs. Adjust mass, substance, and ΔT to watch q = mcΔT resolve, with sign convention showing exo vs. endothermic.

Scrub through a heating or cooling curve to read live temperature, phase, and formula per segment. Slopes and plateaus show why T stalls during phase changes.

Pick a reaction and scrub moles to watch q = n × ΔH scale on a shared heat bar. Compare exo vs. endo magnitudes across combustion, thermite, and photosynthesis.

Choose a reaction and see every bond drawn on the reactant and product molecules. A bar chart tallies energy in vs. out to show why the net ΔH is positive or negative.

Pick a reaction and watch stacked ΔH°f bars build for reactants and products on a shared kJ axis. Signed subtraction gives ΔH°rxn — element species pin to zero.

Step through intermediate reactions on a multi-level energy diagram. Cancelled species strike through and ΔH values accumulate to match the direct path.

Particles flash and convert as a reaction runs toward equilibrium. Concentration curves build above, and a live Q vs. K readout shows when equilibrium is reached.

Drag concentration sliders and watch a Q marker slide along a log-scale axis relative to K. Color and direction arrow flip instantly to show which way the reaction shifts.

Set initial concentrations and one measured equilibrium value. Stoichiometry auto-fills the Change and Equilibrium rows, and K appears substitution-by-substitution below

Click across 7 real AP reactions pinned on a log-K number line from 10⁻³⁰ to 10³³. A particulate flask rebalances red-to-green so a glance shows how far each reaction proceeds

Enter Ka and initial concentration to auto-fill an ICE table. Steps through the quadratic solution, validates the 5% approximation, and calculates final pH.

A piston vessel of shaded molecules, with a thermometer and a live pressure gauge. Add a species, heat it or compress it, and a real equilibrium solver walks Q back to K on a concentration graph.

Perturb equilibrium with concentration or temperature buttons and watch Q(t) and K(t) trace on a log timeline. Concentration jolts Q, temperature jolts K, Q relaxes to K.

A saturated beaker solved from Ksp itself: watch molar solubility built up step by step, then push Qsp above or below Ksp and see the crystal bed grow or dissolve. Ranks 6 salts by Ksp and by s.

Add a common ion to a saturated solution and watch Q exceed Ksp as precipitate forms. Side-by-side beakers compare solubility in pure water vs. common ion solution.

Step through proton transfer from acid to water with animated arrows and highlighted conjugate pair brackets. Choose from 10 acids and see Kₐ, Kb, and pKₐ resolve.

Drag the pH slider or type any of the four values and all update instantly. Color-coded gradient bar places 10 real substances across the scale.

Side-by-side animated beakers at equal concentration: strong acid fully splits, weak acid shows partial dissociation with live particle counts, pH, and % dissociation.

A 2×2 matrix of acid × base types shows the titration curve and a live BCA table at chosen volumes. Read pH, regime, and major species for each mixing case.

Drip titrant into an animated flask and watch the pH curve build live. Covers strong/weak, diprotic, and triprotic reactions with indicator color changes.

Nine indicator rows show acid-to-base color gradients across a pH axis. Select a titration type and each indicator is rated good, ok, or poor for that equivalence point.

Titrate diprotic and triprotic acids against NaOH. A synced speciation chart below the curve tracks the mole fraction of every species as volume increases.

Deprotonate real acids drawn as full Lewis structures and watch the conjugate base spread its charge over equivalent oxygens. Compare measured pKₐ from 15.7 down to −8.

Slide pH across sigmoidal HA and A⁻ speciation curves and watch a particulate beaker flip its mix at pKₐ. Compare 8 weak acids to see how each 1-unit gap shifts the ratio 10×.

Add acid or base and watch buffered vs. unbuffered pH curves split apart. Animated particles show the HA/A⁻ ratio shift as Henderson-Hasselbalch recalculates.

Drag [HA] and [A⁻] sliders and watch pH = pKₐ + log([A⁻]/[HA]) substitute term by term across 6 weak acids. Watch the pH bead land inside the pKₐ ± 1 buffer zone.

Adjust concentration and HA/A⁻ ratio to shift the β vs. pH capacity curve. A stacked chart compares buffered vs. pure water pH response to added acid or base.

Sweep the pH slider from 0 to 14 and watch a saturated beaker's salt pile grow or shrink. Compare 5 salts to see when a weak-base or hydroxide anion makes solubility pH-sensitive.

Cycle through every microstate arrangement for N particles and compare a small vs. large container. Solid, liquid, and gas phases animate below.

Pick a reaction and watch coefficient-scaled S° bars stack on a shared J/mol·K axis. Signed subtraction gives ΔS°rxn, with phase-colored bars hinting at signs.

Slide ΔH, ΔS, and T to move a dot along the ΔG vs T line. A 2×2 quadrant grid and competing bar charts show when reactions are spontaneous.

A reaction-coordinate diagram and two gauges for Favorability (ΔG°) and Rate (Arrhenius k). Drag Eₐ and T to see when a favored reaction stalls.

Adjust concentrations and T for 4 reactions; a beaker of particles and a ΔG vs ln Q line show ΔG = ΔG° + RT ln Q flipping sign as Q crosses K.

Pick a salt and slide T to break ΔG°soln into three factors — lattice cost, solvent cavity, and ion–dipole hydration. Watch the big ΔH terms nearly cancel to a small net ΔG°.

Toggle 4 biological systems between isolated and coupled. An unfavorable reaction chains to ATP hydrolysis through a shared intermediate, and the summed ΔG° flips negative.

Switch between galvanic and electrolytic modes with 5 electrode pairs. Animated electrons and ions flow while half-reactions and cell voltage update live.

Pick two half-reactions to set cathode and anode. The cell is drawn from them, electrodes and all, then E°cell, ΔG° = −nFE° and K follow step by step.

Dial ion concentrations and watch a dot slide along a live E vs log Q chart. Voltmeter color shifts as E crosses zero — showing exactly when the cell dies.

Set current, time, and metal to watch deposit grow on the cathode. The right panel walks every step: q = I×t, mol e⁻, mol metal, final mass.

Run an electroplating cell and watch the anode dissolve as glowing ions drift across and coat the cathode. Progress bar tracks plating completion.

Read the bottom of an animated meniscus to ±0.01 mL. Practice single readings or volume delivered, with feedback on parallax and top-of-meniscus errors.

Drag the eye position up or down and watch the apparent meniscus reading shift. Shows true vs. apparent reading and quantifies parallax error in real time.

Interpolate between scale markings on a randomized analog thermometer. Practice °C only, °F only, or both with scored conversion problems.

Drag the three riders to balance an unknown mass. The needle pivots and turns green when balanced — live reading reveals the answer breakdown.

Annotated side-by-side diagrams of volumetric vs. graduated pipettes with a comparison table and step-by-step usage procedures for each.

Switch between barometer, open-tube, and closed-tube manometer modes. Adjust mercury heights and solve 12 randomized pressure calculation problems.

Before-and-after beakers show water rising as a steel cube submerges. ΔV gives the object's volume — works for any irregular shape.