NAME: _________________________________ Form 2 (yellow)
November 26, 2001 QUIZ #4 CHEM 101
1) The cyanate ion NCO
-
, has the least electronegative atom carbon in the center. The very unstable fulminate ion, CNO
-
, has the nitrogen in the center. a) Draw three resonance Lewis dot structures for each ion and assign formal charge to each atom. (Use back if necessary). cyanate:
[
..
..
0
]
-
[
..
0 ..
..
]
-
[
..
0 ..
..
]
fulminate:
[
..
..
+1
]
-
[
..
+1 ..
..
]
-
[
..
+1 ..
..
]
b) On the basis of formal charge and electronegativity circle the resonance structure which is the most reasonable.
2) Some new elements have been discovered in my laboratory so I am naming them after myself.
Here are the names and some properties of the elements:
New Element Number of valence electrons Element always obeys
octet rule
Rt = Robertium 4
Mc = McCreadyium 6
Bn = Bowmanium 7
Yes
No
Yes
We have also discovered some new molecules. It is your job to determine the Lewis dot structures and geometric structures of these new molecules using the information in the table. a) RtBn
4
..
..
.. ..
Bn
.. ..
..
SN = 4
LP = 0
Hybridization around central atom: ___sp
3
__ Shape: tetrahedral_ b) McBn
2
..
..
..
..
..
..
Hybridization around central atom: __sp
3
___ Shape: bent
SN = 4
LP = 2 c) McBn
4
..
..
..
Mc
..
..
Hybridization around central atom: __dsp
3
__ Shape: sawhorse
SN = 5
LP = 1
3) Given the bond energy data on the board, calculate the
∆
H o rxn
for the following reaction.
CH
4
(g) + 2H
2
O(g)
!
CO
2
(g) + 4H
2
(g)
∆
H o rxn
= 4(D of C-H) + 4(D of O-H) – 2(D of C=O) - 4(D of H-H)
= 4(413 kJ) + 4(467 kJ) - 2(799 kJ) - 4(432 kJ) = 194 kJ

NAME: _________________________________ Form 2 (yellow)
November 26, 2001 QUIZ #4 CHEM 101
1) The cyanate ion NCO
-
, has the least electronegative atom carbon in the center. The very unstable fulminate ion, CNO
-
, has the nitrogen in the center. a) Draw three resonance Lewis dot structures for each ion and assign formal charge to each atom. (Use back if necessary) cyanate:
[
..
..
0
]
-
[
..
0 ..
..
]
-
[
..
0 ..
..
]
fulminate:
[
..
..
+1
]
-
[
..
+1 ..
..
]
-
[
..
+1 ..
..
]
b) On the basis of formal charge and electronegativity circle the resonance structure which is the most reasonable.
2) Some new elements have been discovered in my laboratory so I am naming them after one of my favorite singers. Here are the names and some properties of the elements:
New Element
El = Elvisium
An = Aaronium
Py = Presleyium
Number of valence electrons Element always obeys
octet rule
4
5
7
Yes
No
Yes
We have also discovered some new molecules. It is your job to determine the Lewis dot structures and geometric structures of these new molecules using the information in the table.
..
..
.. ..
4
Py
.. ..
..
Hybridization around central atom: __sp
3
__ Shape: tetrahedral
SN = 4
LP = 0 b) AnPy
3
Hybridization around central atom: __sp
3
__Shape: trigonal pyramidal
..
..
..
.. ..
..
SN = 4
LP = 1 c) [AnPy
4
]
-
..
..
..
..
[ ]
-
SN = 5
LP = 1
Hybridization around central atom: __dsp
3
__ Shape: sawhorse
3) Given the bond energy data on the board, calculate the
∆
H o rxn
for the following reaction.
CH
4
(g) + 2H
2
O(g)
!
CO
2
(g) + 4H
2
(g)
∆
H o rxn
= 4(D of C-H) + 4(D of O-H) – 2(D of C=O) - 4(D of H-H)
= 4(413 kJ) + 4(467 kJ) - 2(799 kJ) - 4(432 kJ) = 194 kJ