Chapter 21, Problem 79A

Interpretation Introduction

Interpretation:

The number of hydrogen atoms in an alkane having nine carbon atoms and in an alkene with nine carbon atoms and one double bond needs to be determined.

Concept introduction:

Compounds that contains only carbon and hydrogen atoms are said to be hydrocarbons. The hydrocarbons can be saturated or unsaturated classified on the basis of the type of bond present in the compound.

Answer to Problem 79A

The number of hydrogen atoms in an alkane having nine carbon atoms is 20 and the number of hydrogen atoms in an alkene with nine carbon atoms and one double bond is 18.

Explanation of Solution

The hydrocarbon compounds that contains single bond(s) between carbon atom(s) are said to be saturated hydrocarbon whereashydrocarbon compounds that contains multiple bond(s) between carbon atom(s) are said to be unsaturated hydrocarbon. Compounds containing single bonds are said to be alkane and compounds containing double bonds are said to be alkene.

The general formula of alkane is The number of carbon atoms given are 9 so, the value of n is 9 for the general formula. Now, finding the number of hydrogen atoms in the molecule by substituting the value of n in general formula as:

So, a straight chain of 9 carbon and 20 hydrogen atoms is:

The general formula of alkene is The number of carbon atoms given are 9 so, the value of n is 9 for the general formula. Now, finding the number of hydrogen atoms in the molecule by substituting the value of n in general formula as:

So, a straight chain of 9 carbon, 18 hydrogen atoms with one double bond is: