Questão | Responda |
Avagadro's Number | 6.02x10^23 |
Stoitch types in rxns and given info | mol-mol mol-mol-gram gram-mol-mol |
Atomic Masses | grams/mol of a compound: take the atomic masses of each element multiplied by its coefficient and add them all together to get one molar mass for that specific molecule |
Calc average amu (pg. 80) | Dimensional analysis = atoms (amu/atom) amu/atom = the given average atomic mass for that specific isotope |
Determining mass of a sample of atoms | 6.02E^23 amu = 1gram and use dimensional analysis |
mass percent and percent composition | 1. find the mass of each element of the particular molecule 2. Mass of element/ mass of the entire molecule 3. Multiply the ratio by 100% to get a percentage |
Finding the Empirical Formula | review later |
Stoichiometry | The study of quantities of materials consumed and produced in chemical reactions |
Finding AMU of isotopes (eg carbon) | Carbon = 98.89% 12C 1.11% 13C 0.01% 14C Multiply isotope's amu numbers (eg 12) by percentage |
Counting by Weighing | Grams of sample to moles |
Number of atoms in a sample with specified mass | again counting by weighting grams (moles/gram) |
Formulas (EF and MF) | |
Determining EF | 1. Start with grams of each element, %= total mass is 100 grams therefore mass of each element is its own percent 2. Convert the mass--> moles (per. table) 3. Divide each mole value by the smallest number of moles calculated. 4. Round to the nearest whole number. This is the mole ratio of the elements and the subscripts of the empirical formula 5. Use a multiplier if necessary e.g. If one solution is 1.5, then multiply each solution in the problem by 2 to get 3. e.g. If one solution is 1.25, then multiply each solution in the problem by 4 to get 5. |
Determining MF | 1. mm molecular formula/ mm empirical formula = multiplier (ratio from mf to ef) 2. Multiply the subscripts of EF by this multiplier |
Balancing Chemical Reactions | 1. All atoms present in the reactants must be accounted for in the products 2. Important because the balanced equation represents an overall ratio of reactants and products/ helps find how much products and reactants are formed |
LIMITING REACTANTS | 1. the reactant that is consumed first and therefore limits the amounts of products that can be formed 2.Determine which reactant is limiting to calculate correctly the amounts of products that will be formed. |
PERCENT YIELD |
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