Chemistry Reference
In-Depth Information
10. [physical change; Dissolving sugar in water does not result in the production
of a new substance so it represents a physical change. The sugar can be
recovered through evaporation, which is a physical process.]
Lesson 1-5 Review
1.
[activation]—Just think of it as the energy needed to “activate” the reaction,
to get things started.
2.
[endothermic]—Endothermic reactions take energy in, which allows the
products to end up with more potential energy than the initial reactants.
3.
[energy]
4.
[kinetic]
5.
[D. mgh]—Think “mass, gravity, height.”
6.
[yes]—It's possible when the baseball is flying through the air and the truck
is standing still. Remember: If the formula for kinetic energy is 1/2mv
2
, what
is the kinetic energy of the truck when its velocity is zero?
7.
[yes]—If our reference point is the street, the baseball will have more
gravitational potential energy than the truck when the ball is up in the air
and the truck is sitting on the street. If the formula for gravitational
potential energy is mgh, what happens when the height of the truck is zero?
Chapter 1 Examination
1. [p. exothermic reaction]—Think of “exo” as “out,” as in the word,
exoskeleton. Energy comes out of an exothermic reaction.
2. [j. chemical change]—New substances are produced in chemical reactions,
also called chemical changes.
3. [c. compound]—When two or more substances (say, for example, oxygen and
hydrogen) combine chemically, you get a compound (in this case, water).
4. [e. aqueous]—As in the word aquarium, the prefix “aqua-” refers to water.
5. [m. work]—To do work, in this sense of the word, you must exert a force
over a distance. Do you see why a weight lifter that is holding a barbell over
his head is doing no work, while the barbell is motionless?
6. [g. element]
7. [l. extensive property]
8. [s. ternary compound]
9. [b. matter]—Matter is the most general category in our classification
scheme, including mixtures, compounds, and elements.
10. [o. kinetic energy]
