	atoms of a single element can have different masses
	different elements have atoms of different masses
	atoms combine in simple whole number ratios to form compounds
	atoms are not created or destroyed in chemical change
	chemical change is a rearrangement of atoms

3. Hydrogen combines with nitrogen in a 3:14 weight ratio to form ammonia. If every molecule of ammonia contains three atoms of hydrogen and one atom of nitrogen, an atom of nitrogen must weigh:

	3/14 times the mass of a hydrogen atom		14 times the mass of a hydrogen atom
	14/3 times the mass of a hydrogen atom		3 times the mass of a hydrogen atom

4. Dalton suggested that atoms were indestructible and unchangeble to explain:

	why elements are characterized by the mass of their atoms
	why compounds combine in fixed weight ratios in chemical reactions
	why elements combine in fixed weight ratios to form compounds
	why mass is conserved in chemical reactions

5. Hydrogen combines with oxygen in a 1:8 weight ratio to form water. If every molecule of water contains two atoms of hydrogen and one atom of oxygen, an atom of oxygen must weigh:

	1/16 times the mass of a hydrogen atom		8 times the mass of a hydrogen atom
	16 times the mass of a hydrogen atom		1/8 times the mass of a hydrogen atom

Dalton's Atomic Theory
Page 1: Introduction
Page 2: Dalton's assumptions Five steps forward and one step back.
Page 3: Atoms in compounds An "invisible hand" fixes atom ratios in compounds
Page 4: Atoms in reactions Dance of the atoms
Page 5: Learning check Take a quiz on Dalton's Atomic Theory
Page 6: References and resources

General Chemistry Online! Quiz