• law of conservation of matter

  • matter is neither created nor destroyed in a chemical reaction
  • mass before and after reaction = same
  • number of atoms before and after reaction = same

• stoichiometric coefficient

  • coefficient in front of each reactant and product in the balanced equation

• relative atomic mass

  • reference = 1/12th of a carbon-12 atom

    • hydrogen atoms are not used because last time, ppl used to measure atomic mass by measuring reactivity, and hydrogen is not that reactive
    • oxygen is very reactive but chemists used all 3 isotopes of oxygen (16, 17, 18) while physicists only used oxygen-16
    • life is based on carbon matter

    

    the … is cuz extra isotoope, just add like (abundanceX x massX)

• relative isotopic mass vs relative atomic mass

  • relative isotopic mass is for isotopes, relative atomic mass is for atoms

• relative molecular mass

• percentage composition of element in compound

  • proportion of element by mass

  

Triangle Formulas

• empirical formula vs molecular formula
  • molecular = shows actual formula (e.g glucose = c6h12o6)
  • empirical = shows simplified ratio (e.g glucose = ch2o, which is actually formaldehyde)
• mole ratios

• percentage yield

• percentage purity