Oxyacetylene torches produce such high temperature that they are often used to weld and cut metal. When 1.53 g of acetylene (C2H2) is burned in a bomb calorimeter with a heat capacity of 10.69 kJ/K, the temperature increases from 20.486°C to 44.688°C. What is ΔE (in kJ/mol) for this combustion reaction? Enter to 0 decimal places.

Respuesta :

Answer: [tex]4403kJ/mole[/tex]

Explanation:

First we have to calculate the heat absorbed by bomb calorimeter  

Formula used :

[tex]q_b=c_b\times (T_{final}-T_{initial})[/tex]

[tex]q_b[/tex] = heat absorbed by calorimeter = ?

[tex]c_b[/tex] = specific heat of = 10.69 kJ/K

[tex]T_{final}[/tex] = final temperature = [tex]44.688^oC=(273+44.688)K=317.688K[/tex]

[tex]T_{initial}[/tex] = initial temperature = [tex]20.486^oC=(273+20.486)K=293.486K[/tex]

[tex]q_b=10.69kJ/K\times (317.688-293.486)=258.7kJ[/tex]

As heat absorbed by calorimeter is equal to the heat released by acetylene during combustion.

Thus 1.53 gram of acetylene releases heat of combustion = 258.7kJ

So, 26.04 g/mole of acetylene releases heat of combustion [tex]\frac{258.7}{1.53}\times 26.04=4403kJ/mole[/tex]

Therefore, the heat of combustion of acetylene is, [tex]4403kJ/mole[/tex]

The ΔE (in kJ/mol) for this combustion reaction is 4385 kJ/mol

We know that the number of moles = mass/molar mass

where;

  • molar mass of acetylene = 26.04 g/mol

From the given information, the number of moles of acetylene used:

= 1.53 g/26.04 g/mol

= 0.059 mol

When a given mass of fuel is burned in a bomb calorimeter with a known heat capacity, we can estimate the heat evolved during combustion by measuring the temperature change.

Heat evolved = heat capacity × change in temperature

Heat evolved = 10.69 kJ/K × (44.688 - 20.486)K    

Heat evolved = 10.69 kJ/K ×  24.202K

Heat evolved = 258.719 kJ

We know that the heat of combustion ΔE is the amount of heat evolved by the complete combustion of 1 mole of a gas.

[tex]\mathbf{\Delta E = \dfrac{heat \ evolved}{n}}[/tex]

[tex]\mathbf{\Delta E = \dfrac{258.719 \ kJ}{0.059 mol}}[/tex]

[tex]\mathbf{\Delta E = 4385 \ kJ/mol}[/tex]

Learn more about the heat of combustion here:

https://brainly.com/question/10093007?referrer=searchResults