Shells, Subshells and Orbitals The electrons in an atom occupy orbitals, and each orbital holds at most two electrons. Orbitals are grouped into subshells, and subshells into shells labelled by the principal quantum number n = 1, 2, 3 and so on. Each shell contains subshells of the types s, p, d and f, appearing … Read more
How to Use This Worksheet Work through the sections in order. Section A checks the ideas, Section B builds the mixture calculations, and Section C mixes everything the way an exam would. The key skill in this topic is keeping track of which mass you have and which mass you need: the mixture, the component, … Read more
Mixtures Are Not Compounds A pure substance has a fixed composition. Water is always 11.2% hydrogen by mass, and calcium carbonate is always 40.0% calcium, because their formulas fix the ratios. A mixture has no formula. It is two or more substances physically combined, and its composition depends on how much of each part went … Read more
How to Use This Worksheet Work through the sections in order. Section A checks the ideas, Section B builds the formula method, and Section C mixes everything the way an exam would. Use a periodic table and a calculator. Keep full precision through each calculation and round only at the end, because empirical formula ratios … Read more
What Percent Composition Tells You The percent composition of a compound is the percentage of its total mass that comes from each element. It is a property of the compound itself. A pure sample of water is always 11.2% hydrogen and 88.8% oxygen by mass, whether the sample is a drop or a tank of … Read more
How to Use This Worksheet Work through the sections in order. Section A checks the ideas, Section B builds the calculation method, and Section C mixes everything the way an exam would. Use a periodic table and a calculator. Show every step of your working, and write the units or the isotope symbol beside each … Read more
Master AP Chemistry Topic 4.1 with this free practice quiz. Test your skills on evidence of chemical reactions, precipitates, gas evolution, and conservation of mass to prepare for your AP exam. What a Chemical Reaction Is A chemical reaction is a rearrangement of atoms. The atoms in the reactants are regrouped, so new substances appear … Read more
These revision notes cover everything you need for AP Chemistry Topic 3.13: Beer-Lambert Law. Read through the key ideas below, then test yourself with the 18-question quiz. Light In, Light Out: Transmittance A spectrophotometer shines light of one chosen wavelength through a sample and compares what comes out with what went in. Transmittance, T, is … Read more
Welcome to AP Chemistry Topic 3.12. These revision notes build the full story of the photon, from the energy carried by a single packet of light to the photoelectric effect that proved light is quantized. Read through the notes and worked examples below, then check your understanding with the 18-question quiz. One Photon, One Electron … Read more
Master AP Chemistry Topic 3.11 with this free practice quiz. Test your skills on microwave spectroscopy, infrared spectroscopy, and uv vis spectroscopy to prepare for your AP exam. Spectroscopy: How Radiation Meets Matter Spectroscopy is the study of how electromagnetic radiation interacts with matter: how substances absorb, emit and transmit radiation across the whole spectrum. … Read more