Download Chemistry ~ Fall Final Review

Chemistry ~ Fall Final Review
Please Note:
Final is comprehensive over the first semester.
Half multiple choice. Half free response.
Bring a calculator & something to write with.
You may bring a 4x6 note card w/ notes on both sides (MUST be handwritten)
You will be expected to show all work, use correct significant figures and include proper units.
Topics covered:
Measurement: significant figures, sci. notation, guess digits, density
Properties of Matter: atoms/molecules, elements & compounds, chemical/physical changes
History of the atom: models & scientists
Wave calculations: properties of waves, energy, frequency, wavelength
Electron configuration: orbital diagrams, electron configuration, shorthand notation
Periodic Table: metal, nonmetal; valence number; ion formation
Naming: covalent, ionic type I, ionic type II, polyatomic ions
Dimensional analysis: conversion factor, converting units
Mole conversions: mass
mol
particles; % composition,
empirical/molecular formulas
Balancing
DISCLAIMER: These problems include some possibilities for the test. Therefore, the
answer to the question, “If I know everything on this sheet, am I guaranteed an A on the
final?” is NO. For comprehensive review, you must study old test and quizzes,
homework sets, corresponding sections of the text and class notes.
1. How many significant figures are in the following numbers:
a) 10 000
b) 10.0
c) 5 432 009 000
d) 0.0087
e) 3.801 x 109
10 ml
2. Identify the following measurements. Be sure to include the correct significant figures
and units.
9 ml
8 cm
7
3. Perform the following calculations. Include units and the correct significant figures.
a) 3.265 cm + 8.4 cm
b) 2.780 m x 3.4 m
c) 8.9x1012 m2/ 3.56x1014 m
4. The density of iron is 7.80 g/cm3. What is the mass of a 0.892 cm3 sample?
5. Define physical and chemical change.
6. Define element, atom, compound, molecule, mixture, solution.
7. Explain how to determine the # of protons, neutrons and electrons from given
information about atomic mass, atomic number, and the charge on the atom (ion).
8. Describe the models of the atom: Democritus, Dalton, Thomson, Rutherford, Bohr,
Electron Cloud.
9. Use a diagram to define wavelength and frequency. Write the equations that relate
wavelength & frequency and frequency & energy. What is “c”? What is “h”?
10. A beam of light has an energy of 2.34 x 10-18 J. Calculate its frequency and
wavelength.
11. Define Hund’s rule, Pauli’s exclusion principle, Aufbau principle. Draw an orbital
diagram for nitrogen. Indicate where each rule applies.
12. For each of the following atoms/ions provide: (1) electron configuration, (2)
shorthand electron configuration, (3) number of valence electrons, (4) number of
core electrons.
a) boron
b) selenium
c) calcium
d) O2e) Mg2+
13. Provide the name or formula for the following:
a) calcium chloride
b) magnesium oxide
d) iron (II) sulfide
e) Al2O3
g) CCl4
h) SnO2
c) dinitrogen tetrafluoride
f) Pb2O3
i) Na3PO4
14. What is a mole? Why do chemists use the mole?
15. How many atoms are in 5.0 mol of Al? (Use dimensional analysis/units/sig figs)
16. How many mol are in 9.0 g of water?
17. What is the mass of 1.3 x 1023 molecules of calcium sulfate?
18. Determine the % composition by mass of each element in glycerine C3H5(OH)3
19. Determine the molecular formula of a compound that is 87.5% nitrogen and 12.5%
hydrogen by mass. The true molecular mass is 32.0 g/mol.
20. Balance the following chemical equations.
a) ___ FeCl3(aq) + ___ KOH(aq)  ___ Fe(OH)3(s) + ___ KCl(aq)
b) ___ Pb(C2H3O2)2(aq) + ___ KI(aq)  ___ PbI2(s) + ___ KC2H3O2(aq)
c) ___ P4O10(s) + ___ H2O(l)  ___ H3PO4(aq)
d) ___ Li2O(s) + ___ H2O(l)  ___ LiOH(aq)
e) ___ MnO2(s) + ___ C(s)  ___ Mn(s) + ___ CO2(g)
f) ___ Sb(s) + ___ Cl2(g)  ___ SbCl3(s)
g) ___ CH4(g) + ___ H2O(g)  ___ CO(g) + ___ H2(g)
h) ___ FeS(s) + ___ HCl(aq)  ___ FeCl2(aq) + ___ H2S(g)
1)
a) 1
b) 3
2)
a) 7.45 cm
b) 9.20 ml
3)
a) 11.7 cm
b) 9.5 m2
4)
6.96 g
c) 7
d) 2
e) 4
c) 0.025 m
5) physical change – alteration in the appearance, but not the identity of the substance
chemical change – alteration of a substance into a new substance with new properties
6) atom – building blocks of matter
element – simplest form of matter (made up of atoms)
molecule – chemical combination of atoms
compound – chemical comination of elements (made up of molecules)
mixture – physical combination of 2 or more substances
solution – homogeneous mixture where one substance is dissolved in another
7)
atomic number EQUALS number of protons
atomic mass – atomic number = number of neutrons
atomic number – charge = number of electrons
8)
defined the atom –“tiny” indivisible particle
DEMOCRITUS
~ 400 B.C.
Affirmed Democritus definition thru
experimentation
DALTON
Early 1800’s
Discovered electrons (e-) called them corpuscles
THOMSON
Late 1800’s
- Plum Pudding Model / chocolate chip cookie model
- Most of the mass of the atom is located in a small space,
called the nucleus
- The nucleus is positively charged
- Atoms are mostly empty space
- Electrons circle the nucleus
RUTHERFORD
1910
Reformed Rutherford’s model; stated that the
electrons followed fixed paths called orbitals, as
they circled the nucleus
BOHR
1913
Electrons can move b/w orbitals:
gain energy  move up level
lose energy  move down level (gives off light)
Scientists who contributed to model:
Plank, DeBroglie, Schrodinger, Einstein
WAVE MODEL (electron cloud model)
1920’s – Today
9)

f = 2 Hz
E = h*f h = 6.626 x 10-34
c = *f
10)
c = 3 x108 m/s
1 sec
E = 2.34 x 10-18 J
E = h*f
f = E/h = 2.34 x 10-18 / 6.626 x 10-34
f = 3.53 x 1015 Hz
c = *f
8.50 x 10-8 m
c/f = 3 x108 / 3.53 x 1015
11)
Hund’s rule – put one electron in each orbital per sub level before doubling up
Pauli’s exclusion principle (simplified) – electrons have opposite spins
Aufbau principle – fill lowest energy levels first
N (Z=7)
 Hund
2p
2s
 Pauli
 Aufbau
1s
12)
a) boron - 1s22s22p1; [He] 2s22p1; 3; 2
b) selenium - 1s22s22p63s23p64s23d104p4; [Ar] 4s23d104p4; 6; 28
c) calcium - 1s22s22p63s23p64s2; [Ar] 4s2; 2; 18
d) oxide - 1s22s22p6; [Ne]; 8; 2
e) magnesium - 1s22s22p6; [Ne]; 8; 2
13)
a) CaCl2
b) MgO
c) N2F4
d) FeS
f) lead (III) oxide
g) carbon tetrachloride
i) sodium phosphate
14)
mole = Avagadro’s number = 6.02 x 1023
e) aluminum oxide
h) tin (IV) oxide
This many atoms provides a useable amount in the lab. Also, allows chemists to
measure the mass of elements in grams.
15)
5 mol Al * 6.02 x 1023 atoms Al = 3.0 x 1024 atoms Al
1 mol Al
16)
9.0 g H2O * 1 mol H2O = 0.5 mol H2O
18 g H2O
17)
1.3 x 1023 molecules CaSO4 *
1 mol CaSO4
6.02x1023 molecules CaSO4
*
136 g CaSO4
1 mol CaSO4
= 29 g CaSO4
18)
C – 12 x 3 = 36
H–1x8 = 8
O = 16 x 3 = 48 +
92
C: 36 / 92 = 39%
H: 8 / 92 = 9%
O: 48 / 92 = 52%
19)
N: 87.5%  87.5 g / 14 = 6.25 mol / 6.25 = 1
NH2
H: 12.5%  12.5 g / 1 = 12.5 mol / 6.25 = 2
32 / 14 = 2
20)
MOLECULAR FORMULA  N2H4
a) ___ FeCl3(aq) + 3 KOH(aq)  ___ Fe(OH)3(s) + 3 KCl(aq)
b) ___ Pb(C2H3O2)2(aq) + 2 KI(aq)  ___ PbI2(s) + 2 KC2H3O2(aq)
c) ___ P4O10(s) + 6 H2O(l)  4 H3PO4(aq)
d) ___ Li2O(s) + ___ H2O(l)  2 LiOH(aq)
e) ___ MnO2(s) + ___ C(s)  ___ Mn(s) + ___ CO2(g)
f) 2 Sb(s) + 3 Cl2(g)  2 SbCl3(s)
g) ___ CH4(g) + ___ H2O(g)  ___ CO(g) + 3 H2(g)
h) ___ FeS(s) + 2 HCl(aq)  ___ FeCl2(aq) + ___ H2S(g)
BALANCED