| Chemistry Sample notes |
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| * The number of atoms in a mole of any pure substance is called Avogadro's constant. * As the atomic masses of the elements in the priodic table increase, the number of atoms in 1mol of each element remains the same. * If samples of two different elements each represent one mole, then they contain the same number of atoms. * An Avogardo's constant amount of any element is equivelent to 6.02x10^23 particles. * The molar mass of an element is the mass of 1mol of the element. * The atomic mass of Hydrogen is 1.008 amu. The reason that this value is not a whole number is that Hydrogen has more than one isotope. * A chemical formula includes the symbols of the elements in teh compound and subscripts that indicate how many atoms or ions of each type are combined in the simplest unit. * Changing a subscript in a correctly written chemical formula changes the formula so that it no longer represents that compound. * A formula that shows the sumplest whole-number ratio of the atoms in a compound is the empirical formula. * The empirical formula is always the accepted formula for ionic compound. * The empirical formula for a compound shows the symbols of he elements wuth subscripts indicating the smallest whole-number ratio of the atoms. * The empirical fomula may not represent the actual composition of a unit of a molecular compound. |
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