Unit 2: The Chemistry of Life
Week #3
2-1
The Nature of Matter Pgs 35-39
Questions
1. Describe the structure of an atom.
Atoms have a nucleus made up of protons and neutrons. Electrons are in constant motion in the
space around the nucleus.
2.
Why do all isotopes of an element have the same chemical properties? In what way do isotopes of an
element differ?
They have the same number of electrons. They differ in number of neutrons.
3.
What is a covalent bond? An ionic bond?
A covalent bond forms when electrons are shared between atoms. An ionic bond forms when
electrons are transferred.
4.
What is a compound? How are compounds related to molecules?
A compound is a substance formed by the chemical combination of two or more elements in definite
proportions. A molecule is the smallest unit of most compounds.
5.
How do van der Waals forces hold molecules together?
When the sharing of electrons is unequal, a molecule has regions that are charged. An attraction can
occur between oppositely charged regions of nearby molecules.
6.
How are ionic bonds and van der Waals forces similar? How are they different?
In both cases, particles are held together by attractions between opposite charges, but the attractions
are stronger between the ions than they are between the molecules.
Writing an Article
Write an article for your school newspaper on forensic science as a career. Assume that you have
already interviewed a forensic scientist who works for a law enforcement agency. The article should
be about 500 words long. Hint: Consider the interests of your readers.
2-2
1.
The Properties of Water
Pgs 40-43
Questions
Use the structure of a water molecule to explain why it is polar.
The hydrogen atoms form covalent bonds with the oxygen atom. Because of oxygen’s greater
attraction for electrons, there is an unequal distribution of electrons. The oxygen end of the bent
water molecule is negative; the hydrogen end is positive.
2.
Compare acidic and basic solutions in terms of their H+ ions than OH- ion concentrations.
Per volume, there are more H+ ions than OH- in an acidic solution and more OH- ions than H+ ions in a
basic solution.
3.
What is the difference between a solution and a suspension?
In a solution, all components are evenly distributed. In a suspension, undissolved particles are
suspended in the mixture and can settle out over time.
4. What does pH measure?
The pH scale measures the concentration of H+ ions in a solution.
5.
The strong acid hydrogen fluoride (HF) can be dissolved in pure water. Will the pH of the solution be
greater or less than 7?
The pH will be less than 7.0.
Creating a Concept Map
Draw a concept map on the properties of water. Include the following terms in your concept map:
hydrogen bonds, polarity, cohesion, adhesion, capillary action, and solvent.