A sample of hexane [tex]\((C_6H_{14})\)[/tex] has a mass of 0.580 g. The sample is burned in a bomb calorimeter with a mass of 1.900 kg and a specific heat of 3.21 J/g/K. What amount of heat is produced during the combustion of hexane if the temperature of the calorimeter increases by 4.542 K?

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

A. 8.46 kJ
B. 16.1 kJ
C. 27.7 kJ
D. 47.8 kJ



Answer :

Sure, let's analyze the given problem step by step:

1. Determine the Mass of the Calorimeter in Grams:

The mass of the calorimeter is given as [tex]\(1.900 \, \text{kg}\)[/tex]. We need to convert this mass into grams for consistency in the units.

[tex]\[ 1.900 \, \text{kg} = 1.900 \times 1000 \, \text{g} = 1900 \, \text{g} \][/tex]

2. Identify the Specific Heat of the Calorimeter:

The specific heat capacity ([tex]\(C_p\)[/tex]) of the calorimeter is given as [tex]\(3.21 \, \text{J/g/K}\)[/tex].

3. Determine the Temperature Increase:

The temperature increase [tex]\(\Delta T\)[/tex] during the combustion is given as [tex]\(4.542 \, \text{K}\)[/tex].

4. Use the Formula to Calculate the Heat Produced ([tex]\(q\)[/tex]):

Using the formula provided [tex]\( q = m C_p \Delta T \)[/tex]:

- [tex]\(m\)[/tex] is the mass of the calorimeter. We already converted this to grams:
[tex]\[ m = 1900 \, \text{g} \][/tex]
- [tex]\(C_p\)[/tex] is the specific heat capacity:
[tex]\[ C_p = 3.21 \, \text{J/g/K} \][/tex]
- [tex]\(\Delta T\)[/tex] is the change in temperature:
[tex]\[ \Delta T = 4.542 \, \text{K} \][/tex]

Plugging these values into the formula:

[tex]\[ q = 1900 \, \text{g} \times 3.21 \, \text{J/g/K} \times 4.542 \, \text{K} \][/tex]

5. Calculate [tex]\(q\)[/tex] (the Heat Produced in Joules):

Performing the multiplication gives:
[tex]\[ q = 1900 \times 3.21 \times 4.542 \approx 27701.658 \, \text{J} \][/tex]

6. Convert the Heat from Joules to Kilojoules:

Since there are [tex]\(1000 \, \text{J}\)[/tex] in [tex]\(1 \, \text{kJ}\)[/tex]:

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

7. Select the Closest Numerical Option:

Among the given options, the closest value to our calculated result [tex]\(27.701658 \, \text{kJ}\)[/tex] is:
[tex]\[ 27.7 \, \text{kJ} \][/tex]

Therefore, the amount of heat produced during the combustion of hexane is 27.7 kJ.

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