The law of fixed composition

Quiz: Dalton's Atomic Theory

1. 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:

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

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

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

3. 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		1/8 times the mass of a hydrogen atom
	8 times the mass of a hydrogen atom		16 times the mass of a hydrogen atom

4. Dalton said that elements are different distinguished from each other by:

	the density of their solid forms		the charge on their ions
	the weights of their atoms		the shapes of their atoms

5. Which of the following is not a postulate of Dalton's atomic theory?

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

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