Chem 403 class 4

  1. 1.00 grams equal how many mass units
    6.022 x 1023
  2. What is Avogadro's number?
    6.022 x 1023
  3. one mole of an element is......... atoms of an element
    6.022 x 1023
  4. one mole of a compound is............moles of the compound
    6.022 x 1023
  5. moles to grams
    • ´╗┐´╗┐Mass (g) + # moles x # grams
    • mole
  6. grams to moles
    • # moles+ # grams x moles
    • # grams
  7. formula to convert number of moles to the actual number of atoms or molecules of a substance using Avogadro's number
    • # molecules= # mol x (6.022 x 1023) molecules
    • mole
  8. To convert from weight to # of molecules first.......
    the weight to moles then use Avogadro's # to determine the # of molecules
  9. What can you calculate after you know that mass %?
    you can calculate the fraction of a given weight of a compound due to a particular element.
  10. Determining the formula of an unknown compound:
    how do you do this?
    by converting masses to moles, then determine the ratio of the elements in the compound
  11. Whenever you are given a percentage of an element, you can....
    assume any weight you want (100 is the easiest)
  12. quickly how would you solve this:
    A 0.2500g sample known to contain C, H, O is burned completely producing 0.3664g CO2 and 0.1500g H2O
    Mass of CO2 x mass fraction C in CO2
  13. What are isomers?
    different compounds with the same molecular formula
  14. molecules to the left of the arrows are
  15. molecules to the right of the arrow are
  16. to satisfy conservation of mass the equation has to be
  17. Two molecules of H2 react with one molecule of O to form 2 molecules of H2O.
    Can also be read as:
    Two moles of H2 react with 1 mole of O2 to form 2 moles of H2O.
  18. Limiting reactant:
    the reactant that runs out first
  19. excess
    is the compound you are left over with after the limiting reagent stops the reaction
Card Set
Chem 403 class 4
Notes from class 4 chem 403