Chem 219 Module 2 Exam Questions And
Correct Answers
What are hydrocarbons? -Answer Molecules composed of only the elements carbon and
hydrogen
What are the two major classes of hydrocarbons? -Answer Aromatic (benzene) and
aliphatic (alkanes, alkenes, alkynes)
What is the main source of hydrocarbons? -Answer Fossil fuels such as coal, petroleum,
and natural gas obtained by mining and drilling.
What are Alkanes? -Answer They are said to be saturated hydrocarbons because their
skeleton is composed of only C-C single bonds.
How can alkanes exist? - Answer They can be linear, branched or exist in ring
formations called cycloalkanes.
Describe a higher/more complex alkane structure: - Answer They will have more
carbons and/or increased structural diversity.
What is the general formula of Alkanes? - Answer CnH2n+2
The names of the alkanes reflect? - Answer The number of carbons present.
How many isomers does each alkane have from 1-10 - Answer 1,1,1,2,3,5,9,18,35,75
,Give the names of the first ten prefix of alkanes: - Answers Methane, ethane, propane,
butane, pentane, hexane, heptane, octane, nonane, decane.
With increasing molecular weight: - Answers The number of isomers increase.
What does the suffix -ane signify? - Answers Denotes a saturated hydrocarbon. It is used
for all acyclic saturated alkanes
what is nomenclature? -Answer Naming of a molecular structure. Originally they were
named after their source, now they are systemic.
why is nomenclature important? -Answer Because we can't memorize all the prefixes
since a MF composed of carbons can have several different patterns of connectivity.
What do you understand by the term systemic approach? - Answer There are now ways
of naming molecules such that all names given are unique. You can then work out the
structure from just a name and vice-versa.
IUPAC rules for naming branched alkanes: - Answer 1. Location of parent name by
identifying the longest continuous chain of carbons.
2. Number the parent chain. start at end of chain closest to first branch
3. If two continuous chains of equal length are present, choose chain with most
branches
4. If first branch point is equidistant, choose one that results in lowest substituents
5. If substituents are both equidistant then select the numbering so the substituent goes
with higher alphabetic priority.
How are linear alkanes named? - Answer By adding together the prefix indicating the
number to the suffix -ane.
What is a substituent? - Answer Any group attached to the parent chain.
, What are alkyl groups? - Answer Saturated hydrocarbon substituents. You drop the -yl
for -ane.
A one carbon substituent is a methyl group, four carbon is butyl.
What is a locant? - Answer A number used to determine the suffix.
Tells about location of substituants.
If there is more than one of the same substituent on the parent chain? Such as 3 methyl
groups - Answer Additional prefixes with number are added
How would you name 2,3 dimethylpentane? - Answer It is a 5 carbon chain, then it has
substituants on numbers 2, 3 and those are methyl groups.
How are IUPAC systematic names put together? - Answer Locant-(prefix)
substituentparent
If two or more different substituents are present on the parent chain then what
happens? - Answer They are listed alphabetically. Ethyl before methyl
How are halogen atoms as substituents named? - Answer Change the -ine to -o,
chlorine=chloro, bromine=bromo.
propyl or n-propyl - Answer CH3CH2CH2
isopropyl - Answer CH3CHCH3
What does the squiggle bond mean? - Answer Point of attachment to the parent chain.
Butyl or n-butyl - Answer -CH2CH2CH2CH3
sec-butyl - Answer CH3CHCH2CH3
isobutyl - Answer
tert-butyl - Answer
Isobutyl would be alphabetized as? While sec-butyl would be alphabetized as? - Answer
I, B
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Easton. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $11.99. You're not tied to anything after your purchase.