Download Midterm Review Key - Parma City School District

Midterm Review: Due 1-15-11 1-12-11
You will use your class notes, lab materials, and class work assignments to complete
the following Midterm Review.
Lab Equipment
Sketch the piece of lab equipment in each of the boxes below:
Crucible and Lid
Evaporating Dish
Stirring Rod
Bunsen Burner
Beaker
Graduated Cylinder
Test Tube
Erlenmeyer Flask
Spot Plate
Wire Triangle
Safety Goggles
Dropper Bottle
Lab Questions:
1. Explain what happens to a hydrate salt when you heat it.
The hydrate salt loses water content: hydrate –∆-> anhydrous salt and water
2. Why should you wear goggles and aprons in the lab?
To protect yourself in the event of a chemical spill, broken glassware, or fire.
Chemical Formulas Review
1. Empirical Formulas
have the lowest whole number ratio.
2. Molecular Formulas
show the actual number of atoms.
3. In ionic
nonmetal elements.
formulas electrons are transferred between metal and
4. In covalent
nonmetals.
formulas electrons are shared between two or more
Reviewing Ions:
-ide
.
or –ate
.
1. In a chemical name, all group 15, 16, and 17 anions end in the suffix
2. Polytatomic anions with oxygen in them will end in the suffix –ite
3. For polyatomic ions with similar atoms, such as NO31- and NO21-, the one with the lesser number of
-ite
oxygen atoms will end in
-ate
will end in
and the one with the greater number of oxygen atoms
.
4. Two negative ions that contain oxygen, but end in "-ide" are
oxide
hydroxide
and
.
5. Cations with more then one possible charge must have this indicated in
the name with a Roman Numeral
or suffix (-ic or –ous) .
Reviewing Ionic Formulas
Cation
Anion
Show Crossover Rule
Formula
Name
Cr2+
CO32-
Cr2+ CO32-
CrCO3
Chromium (II) carbonate
Chromous carbonate
2+
1-
Pb(NO3)2
Lead (II) nitrate
Na2CO3
Sodium carbonate
Fe2S3
Iron (III) sulfide
ferric sulfide
2
Pb
NO3
2
Pb2+ NO311
Na+
Fe3+
2
CO32-
Na1+ CO32-
S2-
Fe3+ S2-
2
1
2
Mn4+
Ag1+
Zn2+
Ca2+
3
MnO41-
Mn4+ MnO41-
Mn(MnO4)4
Cr2O72-
Ag1+ Cr2O72-
Ag2Cr2O7
C2O42-
Zn2+ C2O42-
ZnC2O4
SO42-
1
4
2
2
Ca2+ SO422
1
2
2
CaSO4
Manganese (IV) permanganate
Silver dichromate
Zinc oxalate
Calcium sulfate
Reviewing Molecular Formulas
Name
Formula
SO2
Sulfur dioxide
CO2
Carbon dioxide
CBr4
Carbon tetrabromide
NO
Nitrogen monoxide
P2 O 5
Diphosphorus pentoxide
NCl3
Nitrogen trichloride
Reviewing Acids
1. Acids that do not have oxygen will have their name start with
acid
end with
hydro-
and
.
2. Acids with polyatomic ions that originally ended in "-ate" will have their name end in
-ic
.
3. Acids with polyatomic ions that originally ended in "-ite" will have their name end in
-ous
.
Anion
Formula
ClO41-
Number of
H Atoms
1
Anion Name
Acid
Formula
Acid Name
perchlorate
HClO4
Perchloric acid
CO3 2-
2
carbonate
H2CO3
Carbonic acid
NO21-
11
nitrite
HNO2
Nitrous acid
SO42-
2
Sulfate
H2SO4
Sulfuric acid
Br-
1
Bromide
HBr
Hydrobromic acid
I-
1
Iodide
HI
Hydroiodic acid
PO43-
3
Phosphate
H3PO4
Phosphoric acid
F-
1
fluoride
HF
Hydrofluoric acid
Mixed Practice for Chemical Formulas
Ionic,
molecular,
or acid
Name
(Give both where needed)
Formula
ionic
magnesium phosphate
Mg3(PO4)2
ionic
iron (II) oxalate
ferrous oxalate
FeC2O4
ionic
strontium carbonate
SrCO3
ionic
chromium (II) chromate
chromic chromate
CrCrO4
Ionic
sodium permanganate
NaMnO4
acid
Sulfuric acid
H2SO4
molecular
ammonia
NH3
ionic
Potassium chloride
KCl
molecular
carbon tetrabromide
CBr4
acid
hydroiodic acid
HI
ionic
cobalt (II) oxide
cobaltous oxide
CoO
molecular
carbon dioxide
CO2
Conversion Review
Fill in the blanks on the following conversions:
1. _1000
_ mg = ______1 ___ g
2. _1000____ L
4. ___12 ____ inches= ____1
= _______1__ kL
5. _____2.02__ g H2 = ____1__ mol H2
6. 6.02x1023
3. __1________ mole = ___22.4___ L
atoms = ____1___ mol
Show the map, conversion factor, and math for the following conversions:
1. If your desk is 0.53m across, what is this dimension in centimeters?
m cm
1 m = 100cm
0.53 m (100cm/1m) = 53cm
2. If you have a helium balloon that is 50.0 L, how many moles of gas are in this
balloon?
L mol
22.4 L = 1 mol
1 mol
50.0 L (
/22.4L) = 2.23mol
3. What is the mass of 1 atom of polonium?
atom
mol
23
6.02 x 10 atoms = 1 mol
1mol
1 atom (
g
1mol Po = 209g
/ 6.02 x 1023 atoms )(209g / 1mol) = 3 x 10-22g
4. How many moles are on 14.3 x 105 g of copper (II) chloride? (CuCl2)
g mol
134.45 g = 1 mol
1mol
14.3 x 105 g (
/
134.45g)
= 1.06 x 104 mol CuCl2
5. What is the mass of 5.6 x 108 molecules of sodium bicarbonate? (NaHCO3)
molecules
mol
6.02 x 1023 molecules = 1 mol
1mol
5.6 x 108 molecules(
foot
g
1mol NaHCO3 = 84.01g
/ 6.02 x 1023 atoms )(84.01g / 1mol) = 7.8 x 10-14g NaHCO3
Significant Figures and Density Calculations
RespondYes or No to the following:
1. All nonzero numbers are significant. Yes
2. All leading zeroes are significant. NO
3. Trailing zeroes are only significant if there is a decimal. Yes
How many significant figures are in the following:
1. 310 m
2
2. 310.0 m
4
3. 3.1 x 102 m
2
4. 0.00310 m
3
Density Calculations: (Make sure you show all work and follow sig fig rules!)
1. A block has a volume of 6.21 x 101 cm3. Its mass is 1.82 x 101 g. Calculate the
density of the block.
V = 6.21 x 101 cm3
m = 1.82 x 101g
D = m/v
D = 1.82 x 101g / 6.21 x 101cm3
D = 0.293 g/cm3
2. Isopropyl alcohol has a density of 0.785 g/mL. What volume should be measured to
obtain 45.50 g of the liquid?
D = 0.785 g/mL
m = 45.40 g
V = m/d
V = 45.50 g / 0.785 g/mL
V = 58.0 mL
Review of Atomic Structure:
1. Sketch the modern model of the atom. Label the nucleus and the electron cloud.
2. What two subatomic particles are located in the nucleus of the atom? What are their
charges?
Proton has a positive charge. Neutron has a neutral charge.
3. What subatomic particle is located in the electron cloud? What is its charge and what
is its relative size compared to the particles in the nucleus?
The electron is located in the electron cloud and has a negative charge.
The electron is extremely small relative to the size of the proton and
neutron.
4. Neon has a mass number of 21. What is its atomic number and how many of each of
the three subatomic particles are found in a neutral atom of neon?
Based on the atomic number of neon, neon has 10 protons. The mass
number is the number of protons + neutrons, so to find the number of
neutrons, you take 21-10 to get 11 neutrons. Since the neon is neutral,
the number of positive protons will equal the number of negative
electrons, so there are 10 electrons.
5. If chlorine has a mass number of 36, how many of each subatomic particle are found
in a neutral atom of chlorine as well as the ion that is formed by chlorine? (Remember
that chlorine is located in group 17).
Based on the atomic number of chlorine, chlorine has 17 protons. The
mass number is the number of protons + neutrons, so to find the number
of neutrons, you take 36-17 to get 19 neutrons. In a neutral atom of
chlorine , protons = electrons, so there would be 17 electrons. Chlorine
forms the ion Cl1-, which means it gains one electron, so Cl1- would have
18 electrons.
6. Determine the atomic mass and chemical symbol for the following:
Isotopic Mass(amu) Percent Abundance
Isotopic Mass(amu) Fraction
83.9134
0.5
83.9134
X
0.005
85.9094
9.9
85.9094
X
0.099
86.9089
7.0
86.9089
X
0.070
87.9056
82.6
87.9056
X
0.826
87.6182 amu
Sr
Chemical Reactions:
Balance AND Classify the following
1. aluminum and oxygen yield aluminum oxide
4Al
+
3O2
2Al2O3
Direct Combination
2. iron (III) oxide and sulfuric acid yield iron (III) sulfate and water
Fe2O3 +
3H2SO4 Fe2(SO4)3
+ 3H2O
Double Replacement
3. magnesium and oxygen yield magnesium oxide
2Mg
+
O2
2MgO
Direct Combination
4. aluminum and copper (II) oxide yield aluminum oxide and copper
2Al
+
3CuO Al2O3 +
3Cu
Single Replacement
5. potassium oxide and water yield potassium hydroxide
K2 O
+
H2O
2KOH
Direct Combination
Write a word equation, balanced molecular equation, ionic equation, and net ionic
equation for the following aqueous reactants: (Make sure you use phase symbols!)
1. aluminum nitrate and potassium hydroxide
Word Equation
aluminum nitrate and potassium hydroxide aluminum hydroxide + potassium nitrate
Balanced Molecular Equations
Al(NO3)3(aq) +
3KOH(aq)
Al(OH)3(s)
+
3KNO3(aq)
Ionic Equation
Al3+(aq) + NO31-(aq) + K+(aq) + OH1-(aq) Al(OH)3(s) + NO31-(aq) + K+(aq)
Net Ionic Equation
Al3+(aq)
+
OH1-(aq) Al(OH)3(s)
Vocabulary:
Define the following
1. Mass Number
= number of protons + neutrons in an atom
2. Atomic Number
= number of protons in an atom
3. Isotope
Atoms of the same element that have different numbers of neutrons.
(They will have the same atomic number, but different mass number)
4. Atomic Mass
We use the average atomic mass which is a weighted average of the mass
of the individual isotopes of an atom.
5. Avogadro's Number
= 1 mol of something: 6.02 x 1023 atoms, molecules, or ions = 1 mol
6. Stoichiometry
Math of chemical formulas and equations.
7. Spectator Ion
Ions present in solution that do not participate directly in a reaction.
8. Cation (include charge and if it gains or loses e's)
Ion with a positive charge that is formed when an atom loses electrons.
9. Anion (include charge and if it gains or loses e's)
Ion with a negative charge that is formed when an atom gains electrons.
10. Polyatomic ion
An ion containing more than one atom. (ex. OH1-, SO42-, NH41+)
11. Chemical Change
Change of substances into other substances through a reorganization of atoms.
(New substance is formed.)
12. Physical Change
A change in the form of a substance, but not in its chemical nature.
(No new substance is formed)
Practice Test
1. D
2. D
3. C
4. A
5. B (Unbalanced equation should be Al + HCl AlCl3 + H2)
6. B
7. A
8. A
9. D
10. A
Work for #10
assume % are grams
convert gmol
22.8g Na (1mol/22.99g) =0.9917 mol Na
21.8g B (1mol/10.811g) = 2.016 mol B
55.4g O (1mol/16.00g) = 3.463 mol O
2.016 mol B
0.9917 mol Na
=
2 mol B
1 mol Na
x2
= 4 mol B
2 mol Na
3.463 mol O = 3.492 mol O
0.9917 mol Na 1 mol Na
Na2B4O7
11. B
Work for #11
molecules
mol
6.02 x 1023 molecules = 1 mol
1mol
3.01 x 1023molecules(
g
1mol = 18.02 g H2O
/ 6.02 x 1023 atoms )(18.02g / 1mol) = 9.01g
X2=
7 mol O
2 mol Na