Cyclohexane [tex] \left( C_6H_{12} \right) [/tex] is one of the components of crude oil. Which shows the balanced combustion reaction for cyclohexane?

A. [tex] C_6H_{12} + O_2 \rightarrow 6 CO_2 + H_2O + \text{heat} [/tex]

B. [tex] C_6H_{12} + O_2 \rightarrow CO_2 + 6 H_2O + \text{heat} [/tex]

C. [tex] C_6H_{12} + 9 O_2 \rightarrow 6 CO_2 + 6 H_2O + \text{heat} [/tex]

D. [tex] C_6H_{12} + 6.5 O_2 \rightarrow 6 CO_2 + H_2O + \text{heat} [/tex]



Answer :

To determine the balanced combustion reaction for cyclohexane ([tex]$\text{C}_6\text{H}_{12}$[/tex]), we need to ensure that the number of atoms of each element (carbon, hydrogen, and oxygen) is the same on both the reactant and product sides of the equation.

### Step-by-Step Solution:

1. Write the general formula for combustion:
Combustion of an organic compound typically involves the compound reacting with oxygen ([tex]$\text{O}_2$[/tex]), resulting in the formation of carbon dioxide ([tex]$\text{CO}_2$[/tex]) and water ([tex]$\text{H}_2\text{O}$[/tex]), along with the release of heat.

[tex]\[ \text{C}_6\text{H}_{12} + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O} + \text{heat} \][/tex]

2. Balance the carbon atoms:
Cyclohexane has 6 carbon atoms. Therefore, we need 6 molecules of [tex]$\text{CO}_2$[/tex] to balance the carbon atoms:

[tex]\[ \text{C}_6\text{H}_{12} + \text{O}_2 \rightarrow 6 \text{CO}_2 + \text{H}_2\text{O} + \text{heat} \][/tex]

3. Balance the hydrogen atoms:
Cyclohexane has 12 hydrogen atoms. Therefore, we need 6 molecules of [tex]$\text{H}_2\text{O}$[/tex] to balance the hydrogen atoms (since each [tex]$\text{H}_2\text{O}$[/tex] molecule has 2 hydrogen atoms):

[tex]\[ \text{C}_6\text{H}_{12} + \text{O}_2 \rightarrow 6 \text{CO}_2 + 6 \text{H}_2\text{O} + \text{heat} \][/tex]

4. Balance the oxygen atoms:
- On the product side, there are 6 molecules of [tex]$\text{CO}_2$[/tex] and 6 molecules of [tex]$\text{H}_2\text{O}$[/tex].
- Each [tex]$\text{CO}_2$[/tex] molecule has 2 oxygen atoms, so 6 [tex]$\text{CO}_2$[/tex] molecules have [tex]\(6 \times 2 = 12\)[/tex] oxygen atoms.
- Each [tex]$\text{H}_2\text{O}$[/tex] molecule has 1 oxygen atom, so 6 [tex]$\text{H}_2\text{O}$[/tex] molecules have 6 oxygen atoms.
- In total, we need [tex]\(12 + 6 = 18\)[/tex] oxygen atoms on the product side.

Since each [tex]$\text{O}_2$[/tex] molecule has 2 oxygen atoms, we need [tex]\(18 \div 2 = 9\)[/tex] [tex]$\text{O}_2$[/tex] molecules:

[tex]\[ \text{C}_6\text{H}_{12} + 9 \text{O}_2 \rightarrow 6 \text{CO}_2 + 6 \text{H}_2\text{O} + \text{heat} \][/tex]

Thus, the balanced combustion reaction for cyclohexane is:

[tex]\[ \text{C}_6\text{H}_{12} + 9 \text{O}_2 \rightarrow 6 \text{CO}_2 + 6 \text{H}_2\text{O} + \text{heat} \][/tex]

Therefore, the correct answer is:

C. [tex]$\text{C}_6\text{H}_{12} + 9 \text{O}_2 \rightarrow 6 \text{CO}_2 + 6 \text{H}_2\text{O} + \text{heat}$[/tex]