Question

name
che 151
homework: module 10 - organic compounds

1. what is the chemical formula for the following molecules

a. an alkane with 9 carbons:
____
b. an alkene with 5 carbons (assume 1 double bond):
____
c. an alkyne with 8 carbons (assume 1 triple bond):
____

Explanation:

Step1: Recall the general formula for alkanes

The general formula for alkanes is \(C_nH_{2n + 2}\). For \(n=9\) (9 carbons), substitute \(n\) into the formula.

$$H=2\times9 + 2=20$$

So the formula is \(C_9H_{20}\)

Step2: Recall the general formula for alkenes

The general formula for alkenes with one double - bond is \(C_nH_{2n}\). For \(n = 5\) (5 carbons), substitute \(n\) into the formula.

$$H=2\times5=10$$

So the formula is \(C_5H_{10}\)

Step3: Recall the general formula for alkynes

The general formula for alkynes with one triple - bond is \(C_nH_{2n-2}\). For \(n = 8\) (8 carbons), substitute \(n\) into the formula.

$$H=2\times8-2 = 14$$

So the formula is \(C_8H_{14}\)

Answer:

a. \(C_9H_{20}\)
b. \(C_5H_{10}\)
c. \(C_8H_{14}\)