What is happening in this picture?
Pizza is a meal enjoyed by many children
and adults. This one has bacon, olives, and
extra cheese.
ThinkCritically*
1. Explain which classes of biological chem icals are in
the ingredients of this meal.
2. Can any of the ingredients be considered acidic?
3. Explain which ingredients are acidic and what the
term
acidic
means.
4. W hat types of chemical reactions will take place in
the d igestive system after som eone eats the pizza?
NATIONAL
GEOGRAPHIC
Self-Test
(Check your answers in Appendix C.)
1.___________ is the most common compound in the body.
a. Protein
b. Fat
c. Carbohydrate
d. Water
Use this figure for questions 2-4.
2. In the figure,___________ contributes to atomic mass num-
ber.
a.
A
b. B
c. C
d. B + C
3. The particle labeled A in the figure is___________ .
a. a proton
b. an electron
4.
What is the atomic number of the atom shown in the figure?
a.
2
b. 4
c. 6
d. 12
0 9
o o
9
9
9
9
9
9
9
9
Cl
9
9
9
9
O O
9
9
Use this figure for questions 5-6.
5.
The chemical bond between the two atoms shown in the figure
is ___________ bond.
a. a covalent
b. a hydrogen
c. an ionic
d. a polar covalent
6.
When dissolved in water, the sodium and chlorine shown in
the figure separate as ions. Which of the following terms best
describes the solution that is formed?
c. a neutron
a. acid
b. salt
c. base
d. carbohydrate
d. a valence electron
46 CHAPTER 2
Introductory Chemistry
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