Chemistry 100
Hour Exam 9/26/01
Part I -- Short Answers
(40 points total)
There were three versions of this section and the questions were different.
1. Write the
symbol for the elements:
(2 points each)
- Chlorine ______
- Calcium ____________
- Potassium ______________
2. Write the
name of the element with the symbol
(2 points each)
- Fe _______________
- He _________________
- K ___________________
3. Name two important atmospheric pollutants and one source for each
(Not CO2)(8 points)
- carbon monoxide
- incomplete combustion (cars engines, cigarettes)
- sulfur dioxide
- volcanos, burning high sulfur coal or petroleum, some metal refining processes
- ozone
- product on photochemical smog
- nitrogen oxides
- lightning, high temperature engines
- formaldehyde ( Interior Pollution)
- other possibilities
-
these responses need to be fairly specific to get credit
- CFC's are a marginal answer (not toxic, but has secondary problems)
4. Write these numbers in power of ten notation (2 pts each)
-
- 0.00065 = 6.5 x 10 -3
- 16,200= 1.62 x 10 4
5.
Vocabulary
(2 points each)
- a. Atoms with the same number of protons but different numbers of neutrons are said to be ISOTOPES of the same element.
- b. The portion of the atmosphere containing the ozone layer is called the STRATOSPHERE.
- c. The major process that removes CO2 from the air is _PHOTOSYNTHESIS__.
6.
Define a CFC ("freon"), an important use of CFC,
and brief statement of why CFC use is being reduced: (10 points)
- CFC= chlorofluorcarbon (a small molecule with carbon center and Cl- F- and perhaps H- bonded to the carbon)
- CFC uses-- propellants, refrigerants, foaming agents, fire fighting
- CFC reaches stratosphere, last , destroys ozone
- again, vague answers won't get full credit
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