CEM 141 Exam 3 2025/2026 Exam
Questions and Verified Answers |
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Covalent Bonds - 🧠 ANSWER ✔✔-Valence electrons of one atom attracted to
nucleus of other atom
-Electrons are located between nuclei
-Bond formation lowers the PE of the system and stabilizes the system.
Why is carbon so important? - 🧠 ANSWER ✔✔-Forms four bonds.
-Can bond with C,H,O,N,S,P
-Properties of these compounds are emergent.
Valence Bond Theory - 🧠 ANSWER ✔✔-The idea that covalent bonds are formed
when orbitals of different atoms overlap
,CH4 forms ____________ orbitals - 🧠 ANSWER ✔✔hybridized; sp3 hybridization
on the carbon atom
Draw CH4 - 🧠 ANSWER ✔✔
Drawing Lewis Structures (rules) - 🧠 ANSWER ✔✔1. Sum of valence electrons.
2. draw skeleton structure.
3. Use 2 e- for each bond.
4. Make sure each atom (except H) has 8 electrons by adding lone pairs.
5. If there are not enough electrons form multiple bonds.
What is an isomer? - 🧠 ANSWER ✔✔molecules that have the same type and
number of atoms but are bonded together in a different arrangement.
Generic hydrocarbon formula - 🧠 ANSWER ✔✔C(n)H(2n+2)
Sigma bonds allow ___________ __________ of the bonded atoms - 🧠 ANSWER
✔✔free rotation
Sigma bond - 🧠 ANSWER ✔✔
Pi bond - 🧠 ANSWER ✔✔Whenever pi bond is present, then so is sigma bond.
, Alkenes - 🧠 ANSWER ✔✔-Hydrocarbons with one or more carbon-carbon double
bonds.
-One sigma bond, one pi bond.
- Restricted rotation around the double bond.
-C is sp2 hybridized.
Triple Bonds - 🧠 ANSWER ✔✔-C - sp hybridized
-One sigma bond
-Two pi bonds
-High electron density between atoms.
Formal Charge - 🧠 ANSWER ✔✔Formal charge = (# electrons the atom can use
for bonding) - (# electrons the atom "owns" when bonded)
FC on O = 6 (# valence electrons) - (1/2 x 6) (bonding electrons) - 2 (lone pair
electrons)
= 6 -5 = +1
VSEPR - 🧠 ANSWER ✔✔Valence Shell Electron Pair Repulsion.
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Questions and Verified Answers |
Already Graded A+
Covalent Bonds - 🧠 ANSWER ✔✔-Valence electrons of one atom attracted to
nucleus of other atom
-Electrons are located between nuclei
-Bond formation lowers the PE of the system and stabilizes the system.
Why is carbon so important? - 🧠 ANSWER ✔✔-Forms four bonds.
-Can bond with C,H,O,N,S,P
-Properties of these compounds are emergent.
Valence Bond Theory - 🧠 ANSWER ✔✔-The idea that covalent bonds are formed
when orbitals of different atoms overlap
,CH4 forms ____________ orbitals - 🧠 ANSWER ✔✔hybridized; sp3 hybridization
on the carbon atom
Draw CH4 - 🧠 ANSWER ✔✔
Drawing Lewis Structures (rules) - 🧠 ANSWER ✔✔1. Sum of valence electrons.
2. draw skeleton structure.
3. Use 2 e- for each bond.
4. Make sure each atom (except H) has 8 electrons by adding lone pairs.
5. If there are not enough electrons form multiple bonds.
What is an isomer? - 🧠 ANSWER ✔✔molecules that have the same type and
number of atoms but are bonded together in a different arrangement.
Generic hydrocarbon formula - 🧠 ANSWER ✔✔C(n)H(2n+2)
Sigma bonds allow ___________ __________ of the bonded atoms - 🧠 ANSWER
✔✔free rotation
Sigma bond - 🧠 ANSWER ✔✔
Pi bond - 🧠 ANSWER ✔✔Whenever pi bond is present, then so is sigma bond.
, Alkenes - 🧠 ANSWER ✔✔-Hydrocarbons with one or more carbon-carbon double
bonds.
-One sigma bond, one pi bond.
- Restricted rotation around the double bond.
-C is sp2 hybridized.
Triple Bonds - 🧠 ANSWER ✔✔-C - sp hybridized
-One sigma bond
-Two pi bonds
-High electron density between atoms.
Formal Charge - 🧠 ANSWER ✔✔Formal charge = (# electrons the atom can use
for bonding) - (# electrons the atom "owns" when bonded)
FC on O = 6 (# valence electrons) - (1/2 x 6) (bonding electrons) - 2 (lone pair
electrons)
= 6 -5 = +1
VSEPR - 🧠 ANSWER ✔✔Valence Shell Electron Pair Repulsion.
COPYRIGHT©NINJANERD 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE.
PRIVACY STATEMENT. ALL RIGHTS RESERVED
3
