Problem 23 - Chemistry The Central Science

Question

Give the molecular formula of a hydrocarbon containing five carbon atoms that is (a) an alkane, (b) a cycloalkane, (c) an alkene, (d) an alkyne.

Step-by-Step Solution

Answer

The molecular formulas for hydrocarbons containing five carbon atoms are as follows: (a) Alkane: \(C_5H_{12}\) (b) Cycloalkane: \(C_5H_{10}\) (c) Alkene: \(C_5H_{10}\) (d) Alkyne: \(C_5H_8\)

Step 1: (a) Alkane formula

For an alkane with five carbon atoms, we apply the general formula of an alkane, CnH(2n+2), where 'n' equals 5. Plugging the value of n into the formula, we get: C5H[2(5)+2] = C5H12 Hence, the molecular formula of an alkane containing five carbon atoms is C5H12.

Step 2: (b) Cycloalkane formula

For a cycloalkane with five carbon atoms, we apply the general formula of a cycloalkane, CnH2n, where 'n' equals 5. Plugging the value of n into the formula, we get: C5H(2 * 5) = C5H10 Hence, the molecular formula of a cycloalkane containing five carbon atoms is C5H10.

Step 3: (c) Alkene formula

For an alkene with five carbon atoms, we apply the general formula of an alkene, CnH2n, where 'n' equals 5. Plugging the value of n into the formula, we get: C5H(2 * 5) = C5H10 Hence, the molecular formula of an alkene containing five carbon atoms is C5H10.

Step 4: (d) Alkyne formula

For an alkyne with five carbon atoms, we apply the general formula of an alkyne, CnH(2n-2), where 'n' equals 5. Plugging the value of n into the formula, we get: C5H[2(5) - 2] = C5H8 Hence, the molecular formula of an alkyne containing five carbon atoms is C5H8.