Phys 100
Spring 2008
Concepts of Physics: Homework 1
Due: 30 January 2008
1Hobson, Physics: Concepts and Connections, Ch 1 Conceptual Exercise 4, page 28.
2Hobson, Physics: Concepts and Connections, Ch 1 Conceptual Exercise 8, page 28.
3Hobson, Physics: Concepts and Connections, Ch 2 Review Question 2, page 48.
4Hobson, Physics: Concepts and Connections, Ch 2 Review Question 7, page 48.
5Hobson, Physics: Concepts and Connections, Ch 2 Review Question 12, page 48.
6Hobson, Physics: Concepts and Connections, Ch 2 Conceptual Exercise 2, page 49.
7 Composition of Water
Water can be decomposed (by a process called electrolysis) into hydrogen gas and oxygen
gas. Conversely, combining only hydrogen and oxygen produces water. These observations
indicate that a water molecule consists of hydrogen and oxygen atoms. The issue is the way
in which the two types of atoms combine to produce water. One possibility would be that
one atom of hydrogen (H) and one atom of oxygen (O) combine to produce the molecule HO.
Alternatively two atoms of hydrogen (H) and one atom of oxygen (O) combine to produce
the molecule H2O. The issue is to determine which of this is possibly correct. Suppose that
are able to decompose water into hydrogen gas and oxygen gas and that you can capture all
of these gases that are produced. Knowing that the mass of an oxygen atom is 16 times that
of an hydrogen atom, describe how you could determine which of the two types of molecules
(HO or H2O) represents water.
8Hobson, Physics: Concepts and Connections, Ch 2 Conceptual Exercise 6, page 49.
9Hobson, Physics: Concepts and Connections, Ch 2 Conceptual Exercise 22, page 49.
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