Chemistry Paper 1 AQA

• This is good for higher and Foundation Tier double combined Trilogy and triple separate chemistry that's topics 1 to five atoms bonding quantitative chemistry and chemical and energy changes
• Substances are made of atoms, the different types of atoms are represented in the periodic table by a symbol
• Compound


  A substance that contains two or more different types of atoms chemically bonded together
• Atoms change what they're bonded to and how they're bonded through chemical reactions
• Word equation


  A representation of a chemical reaction using words
• Chemical equation


  A representation of a chemical reaction using symbols
• Atoms are not created or destroyed in any chemical reaction, there must be the same number of each type of atom on both sides
• Balancing a chemical equation

  1. Start balancing atoms that are only in compounds

  2. Balance carbons first

  3. Balance hydrogens

  4. Use numbers in front of elements or compounds to multiply them up

  5. Finish balancing the element that has no knock-on effect
• Mixture


  Any combination of any different types of elements and compounds that aren't chemically bonded together
• Solution


  A mixture of a solute (solid dissolved in a liquid) and a solvent (the liquid)
• Separating a mixture


  1. Filtration (for large insoluble particles)

  2. Crystallization (to leave a solute behind after evaporating the solvent)

  3. Distillation (to separate liquids with different boiling points)
• These are all physical processes and not chemical reactions because no new substances are being made
• States of matter


  • Solid (particles vibrate around fixed positions)
  • Liquid (particles are still touching but free to move past each other)
  • Gas (particles are far apart and move randomly)
• Gases can be compressed, while solids and liquids cannot
• Melting or evaporating a substance


  Requires supplying energy, usually in the form of heat, to overcome the electrostatic forces of attraction between the particles
• These physical changes do not involve breaking chemical bonds
• Atom models


  • JJ Thompson's plum pudding model (atom as a positive charge with electrons dotted around)
  • Rutherford's discovery of the small, dense nucleus and mostly empty space in an atom
  • Bohr's discovery of electrons in shells/orbitals
  • Chadwick's discovery of neutrons in the nucleus
• Protons, electrons, neutrons


  • Protons and electrons have equal and opposite charges of +1 and -1 respectively, neutrons have a charge of 0
  • Protons and neutrons have a relative mass of 1, electrons have a very small mass
• Periodic table


  • Bottom number is atomic number (number of protons)
  • Top number is mass number or relative atomic mass (protons + neutrons)
  • Isotopes are atoms of the same element with different numbers of neutrons
• The periodic table was originally ordered by atomic weight, then later grouped by properties
• Electron configuration


  Electrons fill up shells/orbitals around the nucleus, with a maximum of 2, 8, 8, 2 electrons in each successive shell
• Metals and non-metals


  • Metals are to the left of the staircase on the periodic table, they donate electrons
  • Non-metals are to the right of the staircase, they accept electrons
• Groups on the periodic table

  • Group 1 (alkali metals)
  • Group 7 (halogens)
  • Group 0 (noble gases)
• Ions


  Atoms that have gained or lost electrons, forming positive or negative charges
• Ionic bonding


  Formed between a metal atom that donates electrons and a non-metal atom that accepts electrons
• Covalent bonding


  Formed between non-metal atoms that share electrons to gain full outer shells
• Simple molecular/covalent structures


  Individual molecules that can mix together, have relatively low boiling points
• Giant covalent structures


  One continuous network of atoms bonded together, like diamond and graphite, have high melting and boiling points
• Nanoparticles are between 100-2500 nm in size, have a high surface area to volume ratio
• Quantitative chemistry


  Deals with the amounts and masses of substances in chemical reactions
• Mole


  A specific number of atoms or molecules, used to compare amounts of substances
• The atoms that go in must come out in a chemical reaction, so we must balance equations
• Relative formula mass


  The sum of the relative atomic masses of the atoms in a compound
• Some reactions produce a gas product which, if it leaves the reaction vessel, will result in a seeming decrease in mass of the reactants
• Mole


  A specific number of atoms or molecules, used as a way of comparing amounts of substances
• One mole


  The amount of a substance that has a mass equal to its relative atomic or formula mass in grams
• In a balanced chemical equation, the ratio of moles of reactants to products is the stoichiometry
• Calculating mass of product from mass of reactant

  Mass -> Moles -> Moles -> Mass
• Concentration of a solution can be expressed in moles per decimeter cubed
• In a reversible reaction, the reaction will reach equilibrium with some reactants left behind