The Mole

3. - The percent by mass of each element in a compound.
6. - A reaction where a single compound breaks down into two or more simpler substances.
7. - The small number in a chemical formula that indicates the number of atoms of an element in a single molecule.
10. - The "fixed" number in a chemical formula that must never be changed during the balancing process.
12. - The form of a compound remaining after the water of hydration has been removed, often by heating.
14. - The starting substances located on the left side of the yield arrow.
16. - The large number placed in front of a chemical formula in a balanced equation, representing the number of moles.
18. - A reaction involving oxygen and a hydrocarbon, always producing carbon dioxide, water, and heat.
20. - The formula that shows the smallest whole-number ratio of the elements in a compound.

1. - The last name of the scientist credited with the number 6.022E23.
2. - A reaction where two or more simple substances combine to form a single, more complex product.
4. - The only number that can be changed when balancing an equation to represent the number of moles.
5. - The simplest ratio of ions represented in an ionic compound (the "molecule" equivalent for salts).
8. - Elements that naturally exist as pairs (like O2 or Cl2), which must be doubled when calculating molar mass from the periodic table.
9. - A compound that has a specific number of water molecules bound to its atoms.
11. - The mass in grams of one mole of any pure substance, numerically equal to its atomic or formula weight.
13. - A general term used to describe an atom, molecule, or formula unit.
15. - The SI unit used to measure the amount of a substance; equal to the number of atoms in 12 grams of carbon-12.
17. - The substances formed during a chemical reaction, located on the right side of the arrow.
19. - The formula that specifies the actual number of atoms of each element in one molecule of a substance.