CHEM 120 EXAM 3
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1. How are molecular orbitals constructed? Mixing atomic orbitals
2. The mixing of n Atomic orbitals creates ___ Mol- n
ecular orbitals
3. Constructive combination of orbitals leads to a bonding; lower
_________ molecular orbital with ________ energy
than the atomic orbitals
4. destructive combination of orbitals leads to a antibonding, higher
_________ molecular orbital with ________ energy
than the atomic orbitals
5. Each MO holds ___ electrons with ____ spins 2; opposite
6. Bond order = 1/2(# of bonding electrons - # of an-
tibonding electrons)
7. A higher bond order means Stronger shorter bonds
8. if bond order is 0 no bond will form
9. bond order = 1 single bond
bond order = 2 double bond
bond order = 3 triple bond
10. Draw MO diagram and give bond order of of done
H2; H2-;He2; Li2
11. a substance is paramagnetic if __________. This it has unpaired electrons; attracted to
means it is ________ an applied magnetic field
12. a substance is dimagnetic if __________. This it has paired electrons; repelled from
means it is ________ an applied magnetic field
, CHEM 120 EXAM 3
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13. Average mass = (total mass of atoms in sample ) /(#
of atoms in sample)
14. isotopes of the same element have different atomic masses
15. if Cu-63 has a mass of 62.93 and an abundance 63.55
of 69.09% and Cu-65 has a mass of 64.90 and
an abundance of 30.91% what mass is dis-
played on the periodic table?
16. Silver has two naturally occurring isotopes 51.84%
with the following isotopic masses: Ag
108.9047 amu Ag 106.90509 amu. The average
atomic mass of silver is 107.8682 amu. What is
the percentage abundance of the lighter of the
two isotopes?
17. Formula mass- the sum of the atomic masses for the
atoms in a chemical formula
18. Formula mass of CaCl2 110.99 amu
19. Molecular mass The formula mass of a molecular
compound
20. 1 mol 6.02 X 10^23
21. Calculate number of ethanol molecules in 1.25 7.53 x 10^23 C2H6O molecules
mol of ethanol (C2H6O).
22. Molar mass the mass in grams of one mole of a
substance (g/mol)
23. Molar mass is ___________ formula mass equal to
Study online at https://quizlet.com/_5l37kc
1. How are molecular orbitals constructed? Mixing atomic orbitals
2. The mixing of n Atomic orbitals creates ___ Mol- n
ecular orbitals
3. Constructive combination of orbitals leads to a bonding; lower
_________ molecular orbital with ________ energy
than the atomic orbitals
4. destructive combination of orbitals leads to a antibonding, higher
_________ molecular orbital with ________ energy
than the atomic orbitals
5. Each MO holds ___ electrons with ____ spins 2; opposite
6. Bond order = 1/2(# of bonding electrons - # of an-
tibonding electrons)
7. A higher bond order means Stronger shorter bonds
8. if bond order is 0 no bond will form
9. bond order = 1 single bond
bond order = 2 double bond
bond order = 3 triple bond
10. Draw MO diagram and give bond order of of done
H2; H2-;He2; Li2
11. a substance is paramagnetic if __________. This it has unpaired electrons; attracted to
means it is ________ an applied magnetic field
12. a substance is dimagnetic if __________. This it has paired electrons; repelled from
means it is ________ an applied magnetic field
, CHEM 120 EXAM 3
Study online at https://quizlet.com/_5l37kc
13. Average mass = (total mass of atoms in sample ) /(#
of atoms in sample)
14. isotopes of the same element have different atomic masses
15. if Cu-63 has a mass of 62.93 and an abundance 63.55
of 69.09% and Cu-65 has a mass of 64.90 and
an abundance of 30.91% what mass is dis-
played on the periodic table?
16. Silver has two naturally occurring isotopes 51.84%
with the following isotopic masses: Ag
108.9047 amu Ag 106.90509 amu. The average
atomic mass of silver is 107.8682 amu. What is
the percentage abundance of the lighter of the
two isotopes?
17. Formula mass- the sum of the atomic masses for the
atoms in a chemical formula
18. Formula mass of CaCl2 110.99 amu
19. Molecular mass The formula mass of a molecular
compound
20. 1 mol 6.02 X 10^23
21. Calculate number of ethanol molecules in 1.25 7.53 x 10^23 C2H6O molecules
mol of ethanol (C2H6O).
22. Molar mass the mass in grams of one mole of a
substance (g/mol)
23. Molar mass is ___________ formula mass equal to
