Download FALL Final Review KEY

Chemistry FALL Final Review KEY
1. 3.8 g/cm3
2. a. 21
b. 1.29
3. a. 178 cm
b. 150 m
c. 0.0007 m2
d. 1.6 g/cm3
4. Mole: the amount of a substance that is equal to as many entities as there are in 12 grams of Carbon-12.
Avogadro’s Number: 6.02 × 1023
5. 1 Mole of Carbon = 6.02 × 1023 molecules
6. 1 Mole of Magnesium = 24.3 grams
7. a. 5.33 Moles of C
b. 0.125 Moles of He
c. 2.03 Moles od Au
8. a. 8 grams of O
b. 458.9 grams of Ar
c. 1368.5 grams K (*typo on review sheet “400 grams” moles)
9. a. 5.0 moles
b. 3.33 × 101 moles
10. a. 2.71 × 1025 molecules
b. 4.12× 1023 molecules
11. Carbon-12
12. Number of neutrons
13. Lead (z = 82)
Pb-206 Mass Number = protons + neutrons
Mass Number = 206
Protons = 82
Neutrons = 206-82 = 124
14.
Protons = 30
Neutrons = 70 – 30 = 40
Electrons = 30
15. Z-129
16. a. 24.985 × .7899 = 18.946
24.986 × .1000 = 2.4986
25.982 × .1101 = 2.861
b. Mg (magnesium)
c. Mg (z = 12)
(18.946 + 2.4986 + 2.861) = 24.305 amu
17. # protons = # electrons
# neutrons varies depending on the isotope number, but can be calculated by the following equation: (Mass
Number = # protons + # neutrons)
18. Nucleus is very small, contains most of the mass, has a positive charge and is 10,000 times smaller
19. Alpha: helium nucleus
Beta (β): High speed electron
Gamma (γ): High energy x-ray that is very dangerous radiation
20. Spontaneous Decay of unstable nuclei (Too many neutrons)
21. a. (B)
b. (A)
22. a. Mg (z = 12) 1s2 2s2 2p6 3s2
b. K (z = 19) 1s2 2s2 2p6 3s2 3p6 4s1
c. Fe ( z= 26) 1s2 2s2 2p6 3s2 3p6 4s2 3d6
d. O (z = 8)
1s2 2s2 2p4
23. a. Mg (z = 12)
b. K (z = 19)
c. Fe (z = 26)
d. O (z = 8)
24. a.
b.
c.
d.
Mg (z = 12)
K (z = 19)
Fe (z = 26)
O (z = 8)
25. The modern periodic table is organized by ATOMIC NUMBER = PROTONS
26. All atoms of the same element have the same number of PROTONS
27. (1) A and D; Period 3
(2) B and C; Group 1A
(3) A; Sulfur
(4) B, C, D
(5) None
(6) B and C; (ns1)
(7) D (ns2)
28. Trend: Down a column (group) atomic size increases and across a row (period) atomic size decreases left to right
Positive ion (cation) is smaller than the atom
Negative ion (anion) is larger than the atom
Larger elements within the pairs: Rb, Ba, Cs, Se
29. Lithium (Li)
30. Positive ion (cation) is smaller than the atom
Negative ion (anion) is larger than the atom
Br-; Na; F-, Al
31. Elements in the same GROUP (vertical column) have the same number of electrons in the outer energy level
(valence electron)
32. (A) 1s2 2s2 2p6 Noble gas is the most stable and will have a general formula of ns2 np6
(where n=1, 2,3,4…7)
33. Check in your notes for the Electronegativity Trend Diagram; In general it will increase up a group (column) and
increase across a period (row) left to right
34. Highest electronegativity: Fluorine
Lowest electronegativity: Francium
Highest ionization energy: Helium
Lowest ionization energy: Francium
35. Ionic: transfer of electrons between one metal and one nonmetal
Covalent: sharing of electrons between two nonmetals (including hydrogen)
Metallic: electron sea model (fixed positive cations and delocalized negative valence electrons)
a. Covalent
b. Covalent  electrons shared and Ionic bonds  electrons transferred
36. Positive cations are surrounded by negative anions and negative anions are surrounded by positive cations
37. If the difference in electronegativity is greater than 1.7, then it is ionic bonding
If the difference in electronegativity is less than 1.7, then it is covalent bonding (less than 0.5 is nonpolar
covalent and between 0.5-1.6 is polar covalent)
38. NaCl: ionic, NaOH: ionic and covalent, BaSO4: ionic and covalent, LiCl: ionic, CaS: ionic, CH4: covalent,
CO2: covalent, C6H12O6: covalent
39.
Electronegativity Chart
Carbon
2.55
Nitrogen
3.04
Potassium
0.82
Fluorine
3.98
Hydrogen
2.20
Oxygen
3.44
Calcium
1.00
Chlorine
3.98
Barium
0.89
Bromine
2.96
C – N = (3.04-2.55) = 0.49 Covalent (Nonpolar)
K – F = (3.98-0.82) = 3.16 Ionic
H – O = (3.44-2.20) = 1.24 Covalent (Polar)
Ca – F = (3.98-1.00) = 2.98 Ionic
N – Cl = (3.16-3.04) = .12 Covalent (Nonpolar)
Ba – Br = (2.96-0.89) = 2.07 Ionic
40.
* In a compound, each atom except hydrogen
must be surrounded by eight electrons (or 4 pairs
of electrons) like a Noble Gas (OCTECT RULE)
41. H2 (hydrogen), N2 (nitrogen), O2 (oxygen), F2 (fluorine), Cl2 (chlorine), Br2 (bromine), I2 (iodine)
REMEMBER THE ACRONYM BrINClHOF
42. Ba(OH)2
43. Two, X+4Y-2 To get a neutral atom you have to multiply -2 by 2
44. Cobalt (III) Sulfate
Cobalt (II) Sulfate
Cobalt (III) Sulfite
Cobalt (II) Sulfite
Cobalt (III) Sulfide
Cobalt (II) Sulfide
45. a. XCl +1
b. X2(SO4)3 +3
Co2(SO4)3
CoSO4
Co2(SO3)3
CoSO3
Co2S3
CoS
Note: Cobalt (II) = Co+2
Cobalt (III) = Co+3
All charges ( positive and negative) must add to
zero in a neutral compound
c. XPO4 +3
d. X(NO3)2 +2
*Use your Ion Reference Sheet
46. a. Na: 1s2 2s2 2p6 3s1
Cl: 1s2 2s2 2p6 3s2 3s5
b. Na+: 1s2 2s2 2p6 (Na+ loses 3s electron)
Cl-: 1s2 2s2 2p6 3s2 3p6 (Cl- gains electrons from Na)
c. They both attain an octet in their highest energy level making them stable
d. Ionic Bond (sodium is a metal and chlorine is a nonmetal)
e. The resulting structure is called an ionic crystal lattice
47. a.
b.
c.
d.
e.
f.
g.
h.
i.
C3H8 + 5 O2  3 CO2 + 4 H2O
2 Al + 6 HCl  2 AlCl3 + 3 H2
Mg(GaO2)2 + 8 HCl  2 GaCl3 + MgCl2 + 4 H2O
4 CoCl3 + 3 Mg(OH)2  2 Co2O3 + 6 HCl + 3 MgCl2
4 FeS + 7 O2  2 Fe2O3 + 4 SO2
13
8
18
7
48. Law of Conservation of Mass and Matter
49. Changes the identity of the substance (the chemical formula changes)
50. a. 3 Na + FeBr3  3 NaBr + Fe
b. CH4 + 2 O2  2 H2O + CO2
c. PbSO4 + 2 AgNO3  Pb(NO3)2 + Ag2SO4
51. a. Synthesis
b. Double Replacement
c. Combustion
52. a.
b.
c.
d.
d. Single Replacement
e. Double Replacement
f. Decomposition
Zn + Pb(NO3)2  Zn(NO3)2 + Pb
2 AlCl3 + 3 Br2  2 AlBr3 + 3 Cl2 NO REACTION ACCORDING TO ACTIVITY SERIES
2 Al + 6 HCl  2 AlCl3 + 3 H2
Cu + 2 H2SO4  CuSO4 + 2 H2O + SO2
53. a. A = Reactants and B = Products
b. Moles of reactants DECREASE with time and moles of the products INCREASE with time.
c. REACTANTS:
Minimum # moles (0.16) at time 60 min
Maximum # moles (1.00) at time 0 min
PRODUCTS:
Minimum # moles (0) at time 0 min
Maximum # moles (0.84) at time 60 min
d. 24 min
54. Decrease in concentration of reactants over time OR increase in concentration of products over time
55. Temperature, concentration of products or reactants, size of particles, catalysts, surface area, pressure (if it is a
gas)