Chemistry
Sample notes
* 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* Changing a subscript in a correctly written chemical formula changes the formula so that it no longer represents that compound.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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