Chapter 10, Problem 10.18QP

(a)

Interpretation Introduction

Interpretation:

Line formula for given alkanes has to be drawn.

Explanation of Solution

Line formula for 2-methylheptadecane:

From the given name, the parent alkane is found to be heptadecane.  Substituent that is present is a methyl group on carbon-2.  Line formula for 2-methylheptadecane can be drawn as,

Line formula for 17,21-dimethylheptatriacontane:

From the given name, the parent alkane is found to be heptatriacontane.  Substituent that is present are two methyl groups on carbon-17 and carbon-21.  Line formula for 17,21-dimethylheptatriacontane can be drawn as,

Line formula for 15,19-dimethylheptatriacontane:

From the given name, the parent alkane is found to be heptatriacontane.  Substituent that is present are two methyl groups on carbon-15 and carbon-19.  Line formula for 15,19-dimethylheptatriacontane can be drawn as,

Line formula for 15,19,23-trimethylheptatriacontane:

From the given name, the parent alkane is found to be heptatriacontane.  Substituent that is present are three methyl groups on carbon-15, carbon-19 and carbon-23.  Line formula for 15,19,23-trimethylheptatriacontane can be drawn as,

(c)

Interpretation Introduction

Interpretation:

Molar mass of given alkanes has to be calculated..

Explanation of Solution

Molar mass of 2-methylheptadecane:

Molecular formula of 2-methylheptadecane is given as ${\text{C}}_{\text{18}}{\text{H}}_{\text{38}}$.

Molar mass of 2-methylheptadecane is calculated as shown below,

    $\begin{array}{l}\text{Molar}\text{mass}\text{=}\text{18(C)}\text{+}\text{38(H)}\\ \text{=}\text{18(12}\text{.01)}+38(1.008)\\ =216.18+38.304\\ =254.484\text{g/mol}\end{array}$

Therefore, molar mass of 2-methylheptadecane is $\text{254}\text{.484}\text{g/mol}$.

Molar mass of 17,21-dimethylheptatriacontane:

Molecular formula of 17,21-dimethylheptatriacontane is given as ${\text{C}}_{\text{39}}{\text{H}}_{\text{80}}$.

Molar mass of 17,21-dimethylheptatriacontane is calculated as shown below,

    $\begin{array}{l}\text{Molar}\text{mass}\text{=}\text{39(C)}\text{+}\text{80(H)}\\ \text{=}\text{39(12}\text{.01)}+80(1.008)\\ =468.39+80.64\\ =549.03\text{g/mol}\end{array}$

Therefore, molar mass of 17,21-dimethylheptatriacontane is $\text{549}\text{.03}\text{g/mol}$.

Molar mass of 15,19-dimethylheptatriacontane:

Molecular formula of 15,19-dimethylheptatriacontane is given as ${\text{C}}_{\text{39}}{\text{H}}_{\text{80}}$.

Molar mass of 15,19-dimethylheptatriacontane is calculated as shown below,

    $\begin{array}{l}\text{Molar}\text{mass}\text{=}\text{39(C)}\text{+}\text{80(H)}\\ \text{=}\text{39(12}\text{.01)}+80(1.008)\\ =468.39+80.64\\ =549.03\text{g/mol}\end{array}$

Therefore, molar mass of 15,19-dimethylheptatriacontane is $\text{549}\text{.03}\text{g/mol}$.

Molar mass of 15,19,23-trimethylheptatriacontane:

Molecular formula of 15,19,23-trimethylheptatriacontane is given as ${\text{C}}_{\text{40}}{\text{H}}_{\text{82}}$.

Molar mass of 15,19,23-trimethylheptatriacontane is calculated as shown below,

    $\begin{array}{l}\text{Molar}\text{mass}\text{=}\text{40(C)}\text{+}\text{82(H)}\\ \text{=}\text{40(12}\text{.01)}+82(1.008)\\ =480.4+82.656\\ =563.056\text{g/mol}\end{array}$

Therefore, molar mass of 15,19,23-dimethylheptatriacontane is $\text{563}\text{.056}\text{g/mol}$.