A sample of hexane [tex]$\left( C_6 H_{14} \right)$[/tex] has a mass of [tex]$0.580 \, \text{g}$[/tex]. The sample is burned in a bomb calorimeter that has a mass of [tex]$1.900 \, \text{kg}$[/tex] and a specific heat of [tex]$3.21 \, \text{J/g} \cdot \text{K}$[/tex].

What amount of heat is produced during the combustion of hexane if the temperature of the calorimeter increases by [tex]$4.542 \, \text{K}$[/tex]?

Use [tex]$q = m C_p \Delta T$[/tex].

A. [tex]$8.46 \, \text{kJ}$[/tex]
B. [tex]$16.1 \, \text{kJ}$[/tex]
C. [tex]$27.7 \, \text{kJ}$[/tex]
D. [tex]$47.8 \, \text{kJ}$[/tex]



Answer :

To determine the amount of heat produced during the combustion of the hexane sample, follow these steps:

1. Understanding the variables in the problem:
- Mass of the calorimeter, \( m \): 1.900 kg (which is equivalent to 1900 g)
- Specific heat capacity of the calorimeter, \( C_p \): 3.21 J/gK
- Temperature change, \( \Delta T \): 4.542 K

2. Applying the formula for heat:
The formula to calculate the amount of heat (\( q \)) absorbed or released is:

[tex]\[ q = m \cdot C_p \cdot \Delta T \][/tex]

3. Substituting the given values into the formula:
[tex]\[ q = 1900 \, \text{g} \cdot 3.21 \, \text{J/gK} \cdot 4.542 \, \text{K} \][/tex]

4. Calculating the heat produced:
[tex]\[ q = 1900 \times 3.21 \times 4.542 \][/tex]
[tex]\[ q = 27701.658 \, \text{J} \][/tex]

5. Converting the heat produced from Joules to kilojoules:
Since \(1 \, \text{kJ} = 1000 \, \text{J}\),

[tex]\[ q = \frac{27701.658 \, \text{J}}{1000} \][/tex]
[tex]\[ q = 27.701658 \, \text{kJ} \][/tex]

Therefore, the amount of heat produced during the combustion of hexane is approximately \(27.7 \, \text{kJ}\).

So, the correct answer is:
[tex]\[ 27.7 \, \text{kJ} \][/tex]

This matches the third option from the provided choices:
- \( 8.46 \, \text{kJ} \)
- \( 16.1 \, \text{kJ} \)
- \( 27.7 \, \text{kJ} \)
- \( 47.8 \, \text{kJ} \)

Thus, the correct answer is [tex]\(27.7 \, \text{kJ}\)[/tex].