Chemistry 1A Entire Semester Notes Module 1 Matter and ...
Chemistry 1A Entire Semester Notes Module 1 Matter and Measurement Matter Matter (atoms, molecules and ions) Can be pure substances – elements (H – hydrogen) and compounds (H2O – water) Or they can be mixtures (e.g oil mixed with water) o homogenous mixtures (constant ratio of compounds throughout) o heterogeneous mixtures (variation in concentrations of matter throughout, e.g. sand sinking to the bottom of water) Elements combine in fixed ratios. Elements/Chemicals/matter (e.g H) are made of atoms which are made of subatomic particles (protons +, neutrons, electrons -)
An atom has a nucleus at the centre with Protons (+ positive charge) and neutrons inside it and electrons (– negative charge) orbiting around it. Electrons are the things that interact with other atoms. They orbit in levels or “shells”. Each shell has a certain energy level. The further from the nucleus, the higher the energy level. Electrons will jump levels when heated/excited, then go back down when they return to their ground state. Energy is sometimes released as light wavelengths/photons.
Common Compounds to remember Sulphides: something combined with sulphur Oxides: something combined with oxygen Chlorides: something combined with chlorine Acids - compounds of hydrogen and others Bases - compounds of metals with oxygen and hydrogen Salts - compounds of metals and non-metals, such as acids and bases reacting together. Hydrocarbons - compounds that contain only carbon and hydrogen with various ratios methane, ethane, butane, benzene Organic compounds - contain carbon, hydrogen and a range of other elements, especially oxygen and nitrogen Methods of Separating Mixtures Filtration - based on differences in solubility, e.g. it’s not fully dissolved like dirt in water Distillation - based on differences in boiling points Chromatography - based on differences in affinity between the compounds and the substrate separating the pigments in ink
An atom has a nucleus at the centre with Protons (+ positive charge) and neutrons inside it and electrons (– negative charge) orbiting around it. Electrons are the things that interact with other atoms. They orbit in levels or “shells”. Each shell has a certain energy level. The further from the nucleus, the higher the energy level. Electrons will jump levels when heated/excited, then go back down when they return to their ground state. Energy is sometimes released as light wavelengths/photons.
Common Compounds to remember Sulphides: something combined with sulphur Oxides: something combined with oxygen Chlorides: something combined with chlorine Acids - compounds of hydrogen and others Bases - compounds of metals with oxygen and hydrogen Salts - compounds of metals and non-metals, such as acids and bases reacting together. Hydrocarbons - compounds that contain only carbon and hydrogen with various ratios methane, ethane, butane, benzene Organic compounds - contain carbon, hydrogen and a range of other elements, especially oxygen and nitrogen Methods of Separating Mixtures Filtration - based on differences in solubility, e.g. it’s not fully dissolved like dirt in water Distillation - based on differences in boiling points Chromatography - based on differences in affinity between the compounds and the substrate separating the pigments in ink
