Download Exam I CHEM 1303.001 KEY FALL 2009 Part 1. Nomenclature. 10

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Exam I
CHEM 1303.001 KEY
Part 1. Nomenclature. 10 pts. total. 2 pts. each.
FALL 2009
Fill in the names and formulas in the table below.
Name
Formula
potassium chromate
K2CrO4
chlorous acid
HClO2
magnesium hydroxide
Mg(OH)2
tetraarsenic pentoxide
As4O5
vanadium(III) carbonate
V2(CO3)3
Name
Formula
magnesium hydroxide
Mg(OH)2
tetraarsenic pentoxide
As4O5
vanadium(III) carbonate
V2(CO3)3
potassium chromate
K2CrO4
chlorous acid
HClO2
Name
Formula
lithium dichromate
Li2Cr2O7
chloric acid
HClO3
calcium hydroxide
Ca(OH)2
tetraarsenic hexasulfide
As4S6
chromium(III) carbonate
Cr2(CO3)3
2
Name
Formula
calcium hydroxide
Ca(OH)2
tetraarsenic hexasulfide
As4S6
chromium(III) carbonate
Cr2(CO3)3
lithium dichromate
Li2Cr2O7
chloric acid
HClO3
Part 2. Multiple choice (use answer card). 90 pts. total. 3 pts. each.
Indicate the BEST answer for the questions in this section by completely filling in the
appropriate space on the answer card with a #2 pencil. Mark only one space per question.
How many of the following numbers have 4 significant figures?
0.008
1.008
10.080
0.080
8.000
2
The scientist who first proposed the nuclear model of the atom after studying the
scattering of alpha particles by gold foil is
Rutherford.
Express 3.0 × 10–6 pL in mL?
3.0 x 10–15
Isotopes of an element contain different numbers of
neutrons.
Aluminum has a density of 2.70 g/cm3. A sheet of aluminum foil has a mass of 1.20 g
and a total area of 0.0330 m2. What is the thickness of the foil in cm?
0.00135
From the list below, which is the LEAST metallic.
F
3
The alkaline-earth metals are located where in the periodic table?
Group 2A
A common laboratory preparation of oxygen gas is the thermal decomposition of
KClO3 (molar mass = 123) to produce KCl and O2. Calculate the number of grams
of O2 gas produced by the thermal decomposition of 61.5 g of KClO3.
24.0
The total number of electrons in the polyatomic CN– anion is
14
Which of the following is LEAST likely to be covalent?
CaO
The empirical formula of a compound is found to be CF2. If the molar mass of this
compound is 200, determine the molecular formula.
C4F8
All of the following elements exist naturally as diatomic molecules EXCEPT
sulfur
Classify the following four substances as to type of electrolyte.
NH3(ammonia)
NaOH
C12H22O11(sucrose)
NaOH, KBr are strong electrolytes;
NH3 is a weak electrolyte;
KBr
C12H22O11 is a nonelectrolyte
A compound consists of 56.64% Fe and 43.36% S by mass. Determine the empirical
formula of this compound.
Fe3S4
The number of atoms of Mn in 0.250 grams of Mn3O4 is
1.97 x 1021
How many atoms of F are present in 0.20 moles of SF4?
4.8 x 1023
White phosphorus exists as P4 molecules. The number of molecules of P4 that
contains the same number of phosphorus atoms as 3.5 moles of Ca3(PO4)2 is
1.1 x 1024
4
For the following FOUR questions, consider the balanced reaction shown. Molar masses
are given below each formula.
Fe2O3(s)
molar mass:
+
3CO(g)
160
-->
2Fe(s)
28.0
+
3CO2(g)
55.85
44.0
How many grams of Fe will be produced from the reaction of 8.00 g of Fe2O3 with
excess CO?
5.59
If the above reaction yields 2.0 g of Fe, calculate the percent yield?
35.8
If 2.00 moles of Fe2O3 are mixed with 4.00 moles of CO, how many moles of CO2
will be formed?
4.00
How many grams of the excess reagent remain unreacted in the previous question?
107
Group the following elements in pairs that you would expect to show similar chemical
properties:
K
F
P
Na
Cl
N
K and Na;
F and Cl;
P and N
Consider the following balanced equation:
Zn(s)
+
2 AgNO3(aq)
--> 2 Ag(s)
+
Zn(NO3)2(aq)
The correct net ionic equation for this reaction is
Zn(s)
+ 2 Ag+(aq)
--> 2 Ag(s)
+ Zn2+(aq)
Which of the following can act as both a Bronsted acid and base?
HCO3–
HPO42–
NH4+
SO42–
HCO3– and HPO42– ONLY
Mixing of which two solutions will result in formation of a precipitate?
NH4Cl (aq) BaCl2 (aq)
LiS (aq)
Na2CO3 (aq)
KOH (aq)
BaCl2 (aq) and Na2CO3 (aq)
5
How many moles of Ba(OH)2 are needed to completely neutralize 0.50 moles of
H3PO4?
0.75
From the list below, which are strong acids?
HCl H3PO4
HF
H2SO4
HNO3
HCl, H2SO4, and HNO3 ONLY
Silver, Ag, has two naturally occurring isotopes in an approximate 50:50 ratio. One of
these isotopes has a mass of 108.90476 amu. Of the following, which one must be the
other isotope?
107
€
Ag
Consider the reaction between (NH4)2S and MgCl2 in aqueous solution. Which of the
following is the correct net ionic equation for this reaction?
2–
2+
S (aq) + Mg (aq) -->
MgS(s)
The following are properties of the element lithium. Which one is a chemical
property?
It generates hydrogen gas from water.