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Unformatted text preview: Chem 10 Spring 2010 Name WF7245— 10am Sec 1315/1316 12 March2010 G. Stratheam
EXAM 1 Instructions: 1. There are 100 points in this exam containing 6 (six) pages with 16 questions and an extra credit problem,
plus a periodic table/scratch page. Check to make sure you have all the pages. 2. Put your name or initials on each sheet of paper. Make it readable! 3. For each question below, provide an answer.
a. For multiple choice questions, place the correct letter in the space to the left of the answer. If you feel more than one answer is correct, put the best answer. If you feel it necessary, add a short
explanation in any associated space.
b. For all others provide an answer in the space provided. If necessary, you may use an approved
piece of scratch paper. Be sure to indicate that you have done so!
4. If your answer can't be easily read, it won‘t be graded  and gets no points!
5 No cheating. You may have only a dictionary, and your own calculator. No other help or talking.
You have 60 minutes. If you ﬁnish early, you may go on break. Return by 9am for lecture.
6. If you have a question, please come to the front of the room. Some conversions and formulas °C = 5/9(°F32) °C = K273 1” = 25.4 mm
1mi= 1.609km lmin=60 sec 60min= 1 hr 1 in = 2.54 cm 1 yd = 0.9144 In 1 qt = 0.9464 L 1 gal = 4 qt 1 lb (pound) = 0.4536 kg 1 lb = 16 oz 1 mi = 5280 ft Density water = 1.0000 g/mL
l HCF (hundred cubic feet) = 748 gal A. Multiple Choice Questions (10 at 5 points each or 50 points total). Each should take an
average of 1 minute to complete. 2 k l) i tentative explanation for a regularity of nature or observation is: hypothesis b. law
c. theory d. scientiﬁc method
e. experiment .5 2) To how many signiﬁcant digits should the answer to 2.1803 — 1.200 x 1.80006 be rounded?
c. 3 . 4 ,. Z./00 e. 5 ‘ 0. 01 O
3) A particular chlorine (Cl) has 18 electrons. What is the ions charge?
a) None — neutral b) +1 ‘0) +2
.) ‘2. E 4) The volume of ﬂuid depicted by the following graduated cylinder is: a. 30 mL 3 35
C E > 30.0mL c. 31.0 mL 3'3
d.
e 31.00 mL
32 mL 25 I 72 5) In 1987, your professor ran a 5000. meter race. His time was . \
24 minutes 23.8 seconds. Convert this to miles per hour. 5300A” 1510f,“ / ”14 a. 0.2302 mi/hr 7.647 mi/hl‘ ' /, A»
@ Wm ’77 W / c. 13.81 mi/hr d. 15.95mi/hr
e. 22.22 mi/hr 66) You have become the proud owner of a silver coin. You wish to test the coin to
determine if it is silver or another metal. The density of silver is 10.5 g/cm3. You
determine the mass of the coin to be 18.33 g. If the Cd is truly silver, what '5 the volume of the coin? 3 / r, 172/) .15...” 3 a. 0.573 cm3 b. 1 6 m3 c. 192 cm
d. 19.2mL @ my
67) The power in the metric system which is equivalent to micro: a) 10+9 b) 10+3
c 0 d) 10'3
e) 10*6 3 BS) Radioactive technicium— 99 (99Tc)h
4 neutrons, 56 protons an £3 ectrons
@Jtron 43 p tons an 15% ectrons 43 neutrons, 56 protons and 56 electrons
56 neutrons, 43 protons and 56 electrons e) 56 neutrons, 56 protons and 56 electrons C9. What is the symbol of the element in Period 4 and Group IIA? 
a) Be (1) C
b) Mg e) Si 10) ' e of the Group IA metals? a) alkali metals _ b) alkaline earth metals
0 ans1 lon meta s d) halogen metals
e) representative metals Short Answer and F illintheBlanks. SHOW ALL WORK. Point values are given with each
problem. (Total 50 points) 11. Using m; (circle which) of the following two sets of observations, develop three
different scientiﬁc hypotheses to explain the set of observations, and then provide a
repeatable experiment to test each hypothesis. Finally, provide one set of data for each
experiment and indicate if it supports or refutes the hypothesis. (10 points; About 10
minutes) Note, there are no correct answers and you are graded on your understanding
of the scientific method and consistency. Observation Set 1: Three of the six people in your dinner party last night got sick after dinner.
Two of the three had the same main course (dish 1), but the third had a different main course (dish
2), which you also had (dish 2). You did not get sick. You all drank the same white wine, which
all had had before with no ill effects and none of you overimbibed (did not drink too much).
Observation Set 2: When you arrived home early from your business trip, you found a very
handsome/beautiful person of your same sex, unknown to you, exiting from your residence. When
you enter, your signiﬁcantother seems furtive (secretive) and somewhat distressed. It is about two
weeks before Valentine’s Day. You went on the business trip with your boss who is the same sex
as your signiﬁcantother. Hypothesis 1 Hypothesis 2 Hypothesis 3 Experiment and probable results 1 Experiments and probable results 2 Experiment and probable results 3 12. You drive 572 miles on two (2) tanks of gas, which were 10. 3 gal. and 9. 8 gal. The
density: of the gas is 0.805 g/mL The gasoline cost is $3. 079/gal. Fin    ‘ ' What was your milage in miles/ gal? What is your mileage in kin/L? How much did the gas cost in total? How much did the gas cost in euros?
How many grams of gasoline did you use? rm / ”
iii/1’ Z7 (3) (2? $7796???” ”7 E32: @ ém'lﬂl)(?ﬂ,) mm®0ﬁﬂb¢71§7£9f§€um
@ (WWX 13. You are a TombRaider. On your last expedition, you discovered a rare cubic
religious item. It measures 14.33 cm per side. You melt off the gold layer (on the outside
of the cube) and recover 1.83 kg of gold. If the density of gold is 19.31 g/cm3, how thick
was the gold layer on the religious item? (10 points; 5 minutes) HINT: You did this same type of problem in the density lab! D1”; ??? #72 f1) WW 3 aﬁéhm N067 9999‘!» Thickness of Gold Layer: ”17—é? mmAu 14. Isotopes 15. Samarium has the following isotope masses and percentage abundance. Calcu ate e’p
atomic mass of samarium. (6 points; 4 minutes) W
144 3.1% v CoV’eJ :2,
147 15.0% woyk/ / [44/ 1d
148 11.3% M" 34W Eff 51’ a y I
149 13.8% 2. 0 “a, Cort—IL V ?
150 7.4% /l ‘7 ' m M/mﬂ
152 26.7% f4 ‘/ ﬂ; 4
154 22.7% 570 I 5}? 3 L/ 7 Atomic mass: I50: Write the isotope symbols (:He) for each of the following: (4 points; 3 minutes) a) an atom with 10 protons and 10 neutrons 20 / / 7Z— w/l/ﬂ ‘ M b) an atom with 14 protons and 14 neutrons p 24; J7 W
/ 5’ ”Cr ‘5 ’2, 1"! Mar/aye L
d) an atom with 90 protons and 142 neutrons 23 71‘ c) an atom with 24 protons and 26 neutrons 17. 16. Your tube of toothpaste contains 175 grams. If you use a strip 3.0 cm long twice a day,
how many days will the toothpaste last? The strip is 1.0 cm diameter and density of toothpaste is 2.0 g/cm3 . The volume of a cylinder is (H)(radius)2(length) (10
points; 8 minutes) Hint: You did this same type of problem in the density lab. I/ 3677(55092 730cm): :1. 351,, c‘mZ/r/ 4/ 3 \ )9
(2‘ ”Fiﬁ it Z’W/e) : ﬁ/Z w/é/ @
(6/ W2???“ {.7 2 Extra Credit You studied extra hard on one topic that the professors just didn’t cover. So, here is you
chance. Write you own question and then answer it. Grading will be based on originality
(3 pts), correctness of answer (1 pts) and diﬂiculty (1 pts) of the question. (5 points
maximum). ...
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