105af04_sample_e1 - Sept 16 2004 Chem104a 1 1(20 pts 1a(3...

Sept. 16, 2004 Chem104a 1
1. (20 pts.)
1a. (3 pts.) You are an alien on another planet in another galaxy, and you are a scientist.
The laws of Gay-Lussac and Avogadro are known. You find that when volumes are
combined for some alien gaseous elements, you get the following results. A and B are
two alien elements that combine to form a compound. (A
x
B
B
y
) is a new compound whose
composition is unknown. The volumes used in the reaction are given below the equation.
For the gases
2A
s
+ B
t
Î 3(A
x
B
B
y
)
2 vol 1 vol 3 vol
What are the correct formulas for A, B and (AB) based on this information.
A: ______________ B: ________________ AB: ________________
A
2
B A
3
B
B
3
1b. (5 pts.) Absolute zero on the Celsius scale is –273.15 ° C. This defines the Kelvin
scale. In the English system the absolute zero scale is the Rankin scale. What is absolute
zero in Fahrenheit units for the Rankin scale?
F =
9
5
C + 32
F =
9
5
− 273.15
( )
+ 32
F = − 459.67
Answer: ________________
1c. (6 pts.) Give the names for the following compounds:
(NH
4
)
2
Cr
2
O
7
__Ammonium dichromate__
Ca(ClO
4
)
2
____Calcium perchlorate____________
H
2
S ___hydrogen sulfide______________
1d. (6 pts.) Write the correct formula for the following compounds or ions:

Sept. 16, 2004 Chem104a 2
hydrogen sulfate ion __________________________
HSO
4
-
Chromate ion ______________________
CrO
4
2-
Calcium phosphate __________________
Ca
3
(PO
4
)
2
II. (6 pts.) ( Zumdahl, p 76 #34) a.