This document contains an answer key for a chemistry exam covering topics such as: - Chemical formulas, equations, and calculations involving moles, mass, volume, and percent yield - Determining limiting reactants - Distinguishing between scientific laws, theories, elements, compounds, mixtures, and changes of state - Applying principles such as the law of conservation of mass and rules regarding significant figures The answer key provides the question number and correct answer for multiple choice and short answer questions.

1. Answer Key
Testname: CH099A EX FINAL WINTER 2013 REVIEW
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1 uzlnr{ = s,+3 KsoJ {anf
2. a) dinitrogen tetroxide v
b) silver sulfate
c) hydrogen iodide
d) calcium bromide
e) sulfurous acid fJr,r-t b"r r + gC r r{"f " * j _
b) HsPog c)HBr
i llfi^[? ,';,3t1 g o?,Vl7ty,' s+, tsA
--4,'v;:
u!. +1&t .,n 3.[3ii,i*iy'*r, is* *"
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i
3fi?:,
H2Se(g)
f)
, , '' 'T,t 'lus^ 4=1r
#'1,,* z !.1tw,ra }
5F -l su'{srua ^6-.g
u-ur-it.,,lffi]=5.55molesC(carcandcorr) I ?- 4 vl I
=
Y7.'.,,':';'r"'i&'F'pu
,6::'cl,l; %
1.1.2 sH.l#H] = 11.08e10e mores H (carc) = 11.1 mores H (corr) b;;";,"i';,T' '*for
'k / ntt r{'r
22.2 so. =L3srsmoles o (carc) = l 3e moles o (corr) ' ,iL -':;-"
lffi]
*f L*, t,rr.r..luop
/i
.,#=3.9928058(calc)=3.99(corr) orrr;,:;;
* iee $"i.r t-s) ..{.s I.} gl*
=7'98c611'5(calc) = 7'e9 (corr)
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ot
ffi= 1 (calc)= 1'oo (corr) t) cq) tR
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Molecular mass '44 a1 'J - ']ri { 7,a *-"
r :
F"r*"I""r"* =m=z]lu - '*
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Molecular forrnula = Lm.frCgH16O? .t t.<* t r',in .7 1 ", a# L,
3 .- t16'+1 ;"
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13. "C = K - 273= 198 - nn. o.o-
273 = -75"C
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3. Answer Key
Testname: CH099A EX FINAL WINTER 2013 REVIEW
6oog
15. Volume: -Iutt - - =74.7 cm3
densrtv 8.03 g/cm3
16. Theoretical yield:
. . . = Bs sz86zz4 (ca,c)
f#ffi] [T*#]
40 0 g N2
[fr#f#+".'u]
=140 gNaCN (corr)
Percent yield:
x 100 = 17.8571428o/o(calc): 17.9"11(con)
tr##
17. Determination of limiting reactant:
1o.o g H2s -
I I mole HrS I [2 moles HrOl
Hrs j
fAre;f{ mole H2O(calc)
Lz*"r",
^
= C.58685446 = 6.597 mole H2O (corr)
l1 r,rcie Or I [2 moles HrOl
aoogo2.l3a00g6tj"l3*"l.'aj
= 0.83333333 mole H2O (calc) = 0.833 mole H2O (corr)
H2S is the lirniting reactant.
18.02 e HrO
0.587 mole HZO x
1;ffi - 10.57774 g SH2O (catc) = 10.6 g H2O (corr)
1.C
2,D
3.C
4.8
5.D
5.8
7.D
8.A
9.8
10. B
11. C
12. A
13. A
14. B
15. D
16. A
17. A
18. E
19. C
20. A
21,.8
74 of 72

4. Answer Key
Testname: CH099A EX FINAL WINTER 201: REVIEW
22. B
23. A
24. C
25. C
26. B
27. C
28. A
29. A
30. c
31. B
32. C
33. D
34. D
35. B
1. A scientific lar,^,'is different from a theory in that ihe law onlv describes a natural phenomenon; it does not attempt to
explain the phenornenon. A theory is an attempt at explanation.
2. The examples snould follow this rule: Matter has rrass and volume; nonmatter has no mass or volume. Examples of
matter are: air, 'water, metal, rock, solutions. Exa:nples of nonmatter are: energy, vacuum, force, magnetic or electric or
gravitational fields.
3. A substance is a particular kind of matter that has a tmiform and definite composition. A diamond is a substance.
4. No. Changes ir, tire physical properties of a substance do not affect the chemical properties of the substance.
5. A solution is a type of mixture, namely a mixture ihat has a uniform composition. A mixture can have a nonuniform
composition, brit .r solution cannot. AII solutions are mixtures, but not all mixtures are solutions. Salt water (brine) is a
solution; sand in lvater is a mixture.
6. The examples sl'rould follow this rule: A homogeneous mixture is uniform in compositiory whereas a heterogeneous
mixture is not. An example of a homogeneous rr,irture is air; an example of a heterogeneous mixture is soup.
7. An element cannot be broken dolr.'n into simpler .omponents in chemical reactions. Compounds are substances that
can be broken dcrrrn into simpler substances in chemical reactions.
8. Physical changes Co not aiter the composition of ; substance, but chemical changes do. A/hen water is boiled the
resulting gas is still made up of water molecules;ust like those in the liquid. However, when water molecules are
broken down intc elemental hydrogen and oxygt.n in a chemical reaction, the water rnolecules no longer exist. The
latter is a chemical change; the former a physical :hange.
9. The law of conservation of mass states that in anr ;ohysical or chemical reaction" mass is neither created nor destroyed.
According to this iar'r., the total mass the product- in the reaction referred to here rvould be 10 grams, namely the same
mass as that of the reactants.
10. The answer of an addition or subtraction can have no more digits to the right of the decimal point than are contained in
tire measurement with the least number of digits to the right of the decimal point. The answer of a multiplication or
division can have no more significant figures thai-r the measurement having the least number of significant figures. For
these two opera.tions, the position of the decimal ncint has nothing to do with the number of significant figures.
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