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MIDTERM REVIEW
Scientific Method - steps, scientific laws
Name each compound and identify as Molecular or Ionic:
Cu3N I/copper (I) nitride S3O5 M/trisulfur pentoxide
MnS I/manganese (II)sulfide P2F3 M/diphosphorus trifluoride
PbO2 I/lead (IV) oxide
CO2 M/carbon dioxide
HgCl2 I/mercury (II) chloride N4I2 M/tetranitrogen diiodide
Matter - physical & chemical properties
physical and chemical change
pure substances: elements & compounds
mixtures
What ions make up and name:
carbonate
MgBr2 Mg2+Br- magnesium bromide Cu2CO3 Cu2+CO32- copper (II)
Ba(NO3)2 Ba2+NO3- barium nitrate
NH4Cl NH4+Cl-ammonium chloride
Sn3(PO4)2 Sn2+PO43- tin (II) phosphate FeI2 Fe2+I- iron (II) iodide
Reactants & Products:
Law of Conservation of Mass
Metric Measurements:
Scientific notation, Significant figures
Add, subtract, multiply, divide rules
Al2(SO4)3 Al3+SO42- aluminum sulfate Pb(OH)2 Pb2+OH- lead (II) hydroxide
Properties of metals, nonmetals, metalloids:
Laws of Definite & Multiple Proportions
Examples of these laws
Atomic Structure & Periodic Table:
Atomic mass, atomic number
# protons, # electrons, # neutrons
isotopes, average atomic mass
families, periods and their trends
in electronegativity, electron affinity
ionization energy, atomic & ionic radii
Density of solids and liquids: d = m/v
Mass of solid = 4.62 g
Volume of solid = 2.07 mL
2.23 g/mL
% Composition: Na2S2O3 29.1%/40.6%/30.3%, NH4NO3 35.0%/5.0%/60.0%
calcium chloride dihydrate CaCl2•2 H2O 27.3%/48.2%/2.7%/21.8%
sodium phosphate Na3PO4 42.1%/18.9%/39.0%
Types of reactions:
Decomposition, Synthesis,
Single-Displacement, Double-Displacement,
Combustion
Empirical or Molecular Formulas or Both?
C5H10O5 M
C6H12O6 M
C12H17ON B
Find Molecular Mass:
C12H22O11 B
H2O2 M
Na3N E
a) K3PO4 212.2649g b) Ca(NO3)2 164.088g c) Al2(SO4)3 342.13g
d) (NH4)2CO3 96.0852g
How many molecules/formula units are there of each of the compounds above (assume 10.0 g of each compound)?
a) 2.84x1022 ions
b) 3.67x1022 ions
c) 1. 76x1022 ions d) 6.27x1022 molecules
Put these ions together as compounds. Write their formulas and name the compounds:
Ca2+
Al3+
H+
O2CaO
NO3Ca(NO3)2
PO43Ca3(PO4)2
SO42CaSO4
Al2O3
Al(NO3)3
AlPO4
Al2(SO4)3
H2O
HNO3
H3PO4
H2SO4
Balance:
2 PbO2 ------>
2 PbO
+
O2
MnO2
+
4 HCl
------->
MnCl2 +
Cl2 +
2 H2O
3 KOH +
H3PO4 ------->
K3PO4 +
3 H2O
2 Al(NO3)3
+
3 H2SO4 -------->
Al2(SO4)3 +
6 HNO3
Complete and Balance:
Ca(NO3)2 +
2 HCl -------> CaCl2 +
2 HNO3
BaCl2 +
Na2SO4 ------->
BaSO4 +
2 NaCl
2C5H10(g)
+
15 O2 ------->
10 CO2(g) + 10 H2O (l)
Write the compound formulas and balance each equation:
1) aluminum nitrate + sodium hydroxide ------> aluminum hydroxide + sodium nitrate
Al(NO3)3 + 3 NaOH ------> Al(OH)3 + 3 NaNO3
2) copper (II) chloride + potassium sulfate ------> potassium chloride + copper (II) sulfate
CuCl2 + K2SO4 ------> 2 KCl + CuSO4
3) hydrogen carbonate + magnesium hydroxide ------> magnesium carbonate + water
H2CO3 + Mg(OH)2 ------>
MgCO3 + 2 H2O
Balance the following equations:
1) NaOH (aq) + HCl (aq) H20 (l) + NaCl (aq)
2) Pb(NO3)2 (aq) + 2 NaCl (aq)  PbCl2 (s) + 2 NaNO3 (aq)
3) 2 Na3PO4 (aq) + 3 CaCl2 (aq)  6 NaCl (aq) + Ca3(PO4)2 (s)
Calculate the number of moles of the following:
1)
2)
3)
4)
560.0 g of bromine, Br2
73.2 g of magnesium
814 g of Ba(OH)2
472 g of water
3.504 mol
3.01 mol
4.75 mol
26.2 mol
5)
6)
7)
8)
86.6 g of methane, CH4
8.25 g of CaCO3
200.0 g of Al2O3
16.4 L of SO2 at STP
5.40 mol
8.24 x 10-2 mol
1.962 mol
0.732 mol
Calculate the mass in grams of each of the following:
1) 5.25 mol ZnO
427 g; 6.32x1023 atoms
5) 205 mol Al2O3
20900 g; 1.23x1026 molec
2) 12.4 mol HCl
452 g;
6) 42.7 mol Na2CO3 4530 g; 2.57x1025 molec
3) 6.68 mol H2SO4 655 g; 1.61x1023 atoms O 7) 80.3 mol CH4
1290 g; 2.42x1026 atoms
4) 7.5 mol sugar, C6H12O6 1400 g; 4.5x1023 molec 8) 8.273 mol CaCO3 828.0 g; 4.982x1024 molec
1.49x1023atoms
Calculate the volume (at STP) of these gases:
1) 3.20 x 10-3 mol CO2
2) 3.75 mol H2
0.0717 L
84.0 L
3) 0.765 mol CH4
4) 278 g SO2
17.1 L
97.2L
Stoichiometry:
N2 + 3 H2 ----> 2 NH3
Balance
How many g of NH3 will be produced if 37.3 g of H2 are reacted? 2.10x102 g NH3
What volume of N2 is required to react with 271 g of H2 at STP? 1.00x103 L N2
If 2.3 mol of N2 react with 5.7 mol H2, how many mol NH3 will be produced? 3.8 mol NH3
What is the limiting reagent? H2
5) If 3.6 mol of NH3 are produced (from #4 above) what is the % yield from the reaction? 95%
1)
2)
3)
4)
Quantum Mechanics:
1) Why is light emitted in certain frequencies (colors) from an excited atom? e- move from a high E level to a low E level.
Every color emits a specific frequency which corresponds to a specific amount of energy. How does this relate to flame
tests? Each element has its own e- configuration and location in the atom.
2) What is the photoelectric effect and why is it significant in quantum theory? e- must absorb
enough E to produce light. It is significant because light consists of particles and the energy of such a particle Is
proportional to the frequency of light.
3) Give electron configurations (quantum mechanics) for the following:
Ca
1s22s22p63s23p64s2
Ne
1s22s22p6
Na+
1s22s22p6
O21s22s22p6
Zn
1s22s22p63s23p64s23d10
Fe
1s22s22p63s23p64s23d6
S
1s22s22p63s23p4
Fe3+
1s22s22p63s23p63d5
4) Rules for filling electron orbitals: Aufbau principle, Pauli exclusion principle, Hund's rule (Look up)
5) What is the electron configuration for each of the following atoms?
a) vanadium
b) tellurium
c) potassium 1s22s22p63s23p64s1
1s22s22p63s23p64s23d3
1s22s22p63s23p64s23d104p65s24d105p4
Chemical Bonding:
1) Define the following terms: (Look up)
a) valence electrons b) octet rule c) malleable d) ductile
2) Differentiate between ionic, covalent, and metallic bonding in terms of electron location and types of atoms combined.
Ionic - M/NM, e- donated; Covalent - NM, e- shared; Metallic - M, valence e- move freely
3) How many valence electrons do each of the following atoms have?
a) sodium 1 Na
b) argon 8 :Ar:
c) carbon 4
C
d) nitrogen 5 N:
4) Draw the electron dot structure for each of the atoms above.
5) List three properties of ionic compounds. made up of cations & anions, electrically neutral, high BP & MP
6) How many electrons must each of the following atoms lose or gain in order to obtain a noble gas configuration?
What is the resulting charge on each atom? Label each as anion or cation.
a) cesium lose 1/Cs+/cation
b) bromine gain 1/Br-/anion
c) phosphorus gain 3/P3-/anion
7) Define the following terms: (Look up)
a) resonance structures
b) dipole
c) electronegativity
d) London dispersion forces
8) Classify each of the following substances as having ionic bonds, covalent bonds, or metallic bonds.
a) brass metallic
b) sodium bromide ionic
c) methane cov.
d) water cov. e) calcium chloride ionic
9) List all atoms that exist as diatomic molecules. H2O2F2Br2I2N2Cl2
10)Diagram the electron dot structures of each of the following:
a) chlorine
b) CH2Br2
c) CO2
d) SOCl2
e) NH3
:Cl:Cl:
:O::C::O:
:Cl:S:O:
H:N:H
:Cl:
H
11)Describe the VSEPR theory and how it relates to shape. VSEPR stands for "Valence Shell Electron Pair Repulsion";
electron
pairs (lone and bonded) repel each other so the pair moves as far from other pairs as it can. This is way you have the
shapes of linear, bent, trigonal planar, pyramidal and tetrahedral.
12)Differentiate between single, double, and triple bonds in terms of strength, length, and electrons being shared.
Bond
# of electrons shared
Bond Strength
Bond Length
Single
2
Weakest
Longest
Double
4
Triple
6
Strongest
Shortest
13)What are the (1) molecular shapes and (2) bond angles for each of the following molecules? Label the molecules as polar,
molec.
nonpolar, or ionic.
a) ammonia pyr./107°/P b) water bent/105°/P c) carbon dioxide linear/180°/NP d) carbon tetraiodide tetra/109.5°/NP
14)Differentiate between the three main types of intermolecular forces described in your text. Dipole - attraction between P
molec.; Hydrogen - attraction between P molec. (H must be bonded to HOF); Dispersion - attraction between NP
15)Differentiate between the properties of ionically and covalently bonded compounds. Ionic - made up of cations & anions,
usually metal and nonmetal elements, High MP & BP, electrically netural cmpds, can conduct electricity in aq and
molten states; Covalent - made up of nonmetals, forms stable molecules, Low MP & BP, poor or no conductivity
16)Describe each of the following and give three examples of each. Use electronegativities to support your answer.
a) nonpolar covalent bond (CO2)
b) polar covalent bond (H2O)
c) ionic bond (NaCl)
Between 2 nonmetals, forms
Between 2 nonmetals, forms
Between cation & anion
symmetrical molecules
asymmetrical molecules
Held together by charge
0-0.3
0.3-1.7
1.7+
17)Explain each of the following observations on the basis of the forces of attraction that exist between the particles in matter.
a) Water evaporates faster at 40oC than at 20oC. More hydrogen bonds are breaking due to higher T.
b) Propane (C3H8) boils at a lower temperature than water. Propane held together by weaker dispersion forces (NP).
c) Oil is not soluble in water. Propane is nonpolar & is not attracted to polarity of water (no partial charge present).
Nuclear Chemistry:
1) Differentiate between fission, fusion, and nuclear decay. (Look up)
2) Show the symbols used for alpha, beta, and gamma radiation. Rank them according to their ability to penetrate substances.
42He < 0-1e < 00γ
3) Calculate the following:
a) A radioactive compound had a half life of 2.6 years. If you started with 200. g of it, how much would you
have left after 13 years? 6.25g
b) What is the half life for a substance that decayed from 100. g to 25g in 16 days? 8 days
4) Write the balanced nuclear equations for the following:
a) alpha decay of thorium – 230 23090Th -------> 42He + 22688Ra b) alpha decay of 23592U -------> 42He + 23190Th
c) beta decay of thorium – 234 23490Th -------> 0-1e + 23491Pa
d) beta decay of 6629Cu -------> 0-1e + 6630Zn