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| 10720028873 | Carbon 12 | In 1961 it was agreed that this isotope of carbon would serve as the standard used to determine all other atomic masses and would be defined to have a mass of EXACTLY 12 atomic mass units (amu). All other atomic masses are measured relative to this. | 0 | |
| 10720033888 | Mass Spectrometer | A device for measuring the mass of atoms or molecules | 1 | |
| 10720042194 | Average Atomic Masses | Atoms have masses of whole numbers. HOWEVER samples of quadrillions of atoms have a few that are heavier or lighter [isotopes] due to different numbers of neutrons present | 2 | |
| 10720050474 | Percent Abundance | Percentage of atoms in a natural sample of the pure element represented by a particular isotope | 3 | |
| 10720053735 | Percent Abundance Formula | (Number of atoms of a given isotope/total number of atoms of all isotopes of that element) x100 | 4 | |
| 10720094388 | Counting by Mass | 5 | ||
| 10720111878 | Mass Spectrometer to Determine Isoptopic Composition | 6 | ||
| 10720144626 | Mole | The number of C atoms in exactly 12.0 grams of 12C; also a number: 6.02 × 10^23 | 7 | |
| 10720163433 | Avogadro's Number | 6.02 x 10^23 | 8 | |
| 10720182973 | Molar Mass | Rhe sum of all of the atomic masses in a given chemical formula in units of g/mol. It is also equal mass in grams of Avogadro's number of molecules; i.e. the mass of a mole | 9 | |
| 10720207133 | Empirical Formula | The ratio in the network for an ionic substance | 10 | |
| 10720232386 | Formula Weight | Same as molecular weight, just a language problem "molecular" implies covalent bonding while "formula" implies ionic bonding | 11 | |
| 10720262888 | Percent Composition (by mass) | The Law of Constant Composition states that any sample of a pure compound always consists of the same elements combined in the same proportions by mass. | 12 | |
| 10720268638 | Percent Composition Formula | (mass of element/mass of compound) x100 | 13 | |
| 10720328068 | Calculating Empirical and Molecular Formulas | Empirical formulas represent the simplest or smallest ratio of elements within a compound while molecular formulas represent the actual numbers of elements within a compound. The empirical mass is the least common multiple of the molar mass. | 14 | |
| 10720353810 | Hydrates | Waters of hydration or "dot waters". They count in the calculation of molar masses for hydrates and used to "cement" crystal structures together | 15 | |
| 10720360501 | Anhydrous | Without water | 16 | |
| 10720371479 | Chemical Reactions | The result of a chemical change where atoms are reorganized into one or more new arrangements. Bonds are broken [requires energy] and new ones are formed [releases energy]. A chemical reaction transforms elements and compounds into new substances. A balanced chemical equation shows the relative amounts of reactants [on the left] and products [on the right] by molecule or by mole. | 17 | |
| 10720394069 | Stoichiometry | The study of quantities of materials consumed and produced in chemical reactions. | 18 | |
| 10720405670 | Theoretical Yield | The amount of product formed when a limiting reactant is completely consumed. | 19 | |
| 10720405671 | Actual Yield | That which is realistic | 20 | |
| 10720416613 | Percent Yield | The ratio of actual to theoretical yield | 21 | |
| 10720424368 | Percent Yield Formula | (Actual Yield/Theoretical Yield) x100 | 22 |
