Question 1

Which of the following best describes a condensed formula for an organic compound?

Accepted Answer

It groups carbon and hydrogen atoms together, omitting most bonds.

Question 2

Given the molecular formula $C_4H_{10}$, which of the following is a correct condensed formula for a straight-chain structure?

Accepted Answer

$CH_3CH_2CH_2CH_3$

Question 3

In a condensed formula, what do parentheses with subscript numbers indicate?

Accepted Answer

Repeating units of a group attached to the main chain.

Question 4

Which condensed formula represents a molecule with a methyl branch on the second carbon of a propane chain?

Accepted Answer

$CH_3CH(CH_3)CH_3$

Question 5

Convert the condensed formula $CH_3(CH_2)_4CH_3$ into its structural formula. How many carbon atoms are present in the longest chain?

Accepted Answer

6

Question 6

Which of the following condensed formulas contains a branch?

Accepted Answer

$CH_3CH(CH_3)CH_2CH_3$

Question 7

A compound has the condensed formula $CH_3CH_2CH_2CH_2CH_3$. What is the molecular formula?

Accepted Answer

$C_5H_{12}$

Question 8

Which structural feature is indicated by parentheses in a condensed formula such as $CH_3(CH_2)_3CH_3$?

Accepted Answer

A repeating methylene group ($CH_2$) three times.

Question 9

Given the condensed formula $CH_3CH_2CH(CH_3)CH_3$, which carbon is branched?

Accepted Answer

The third carbon

Question 10

Which of the following is the correct condensed formula for the structure shown below?

$\begin{array}{cccccc}
H & H & H & H & H & H \
| & | & | & | & | & |
C & C & C & C & C & C \
| & | & | & | & | & |
H & H & H & H & H & H 
\end{array}$

Accepted Answer

$CH_3CH_2CH_2CH_2CH_2CH_3$

Question 11

If a compound is represented by $CH_3CH_2CH_2CH_2CH_2CH_3$, how many hydrogen atoms are present?

Accepted Answer

14

Question 12

Which condensed formula represents a molecule with two methyl branches on the second carbon of a butane chain?

Accepted Answer

$CH_3C(CH_3)_2CH_2CH_3$

Question 13

What is the condensed formula for a compound with the following structure?

$\begin{array}{cccc}
H & H & H & H \
| & | & | & |
C & C & C & C \
| & | & | & |
H & H & H & H 
\end{array}$

Accepted Answer

$CH_3CH_2CH_2CH_3$

Question 14

Which of the following condensed formulas represents a molecule with a repeating ethylene unit three times?

Accepted Answer

$CH_3(CH_2)_3CH_3$

Question 15

A compound has the condensed formula $CH_3CH_2CH_2CH_2CH_2CH_2CH_3$. What is the molecular formula?

Accepted Answer

$C_7H_{16}$

Question 16

Which condensed formula represents a molecule with a propyl branch on the second carbon of a pentane chain?

Accepted Answer

$CH_3CH(C_3H_7)CH_2CH_3$

Question 17

Which of the following is the correct structural formula for $CH_3CH_2CH_2CH_2CH_3$?

Accepted Answer

A chain of five carbon atoms with single bonds, each end carbon bonded to three hydrogens, and each middle carbon bonded to two hydrogens.

Question 18

If a condensed formula is written as $CH_3CH_2CH_2CH_2CH_2CH_2CH_2CH_3$, how many carbon atoms are present?

Accepted Answer

8

Question 19

Which of the following condensed formulas represents a molecule with a butyl branch on the third carbon of a hexane chain?

Accepted Answer

$CH_3CH_2CH(C_4H_9)CH_2CH_2CH_3$

Structural and Condensed Formulas in Organic Chemistry

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