Respuesta :
Answer : The correct option is, (b) [tex]-1.41\times 10^3kJ/mol[/tex]
Explanation :
First we have to calculate the heat produced.
[tex]q=c\times \Delta T[/tex]
where,
q = heat produced = ?
c = specific heat capacity = [tex]2.47kJ/K[/tex]
[tex]\Delta T[/tex] = Change in temperature = 2.26 K
Now put all the given values in the above formula, we get:
[tex]q=2.47kJ/K\times 2.26K[/tex]
[tex]q=5.5822kJ[/tex]
Now we have to calculate the energy of combustion for one mole of ethylene.
[tex]\Delta H=\frac{q}{n}[/tex]
where,
[tex]\Delta H[/tex] = energy of combustion for one mole of ethylene = ?
q = heat released = 5.5822 kJ
m = mass of [tex]C_2H_4[/tex] = 0.111 g
Molar mass of [tex]C_2H_4[/tex] = 28 g/mol
[tex]\text{Moles of }C_2H_4=\frac{\text{Mass of }C_2H_4}{\text{Molar mass of }C_2H_4}=\frac{0.111g}{28g/mole}=0.00396mole[/tex]
Now put all the given values in the above formula, we get:
[tex]\Delta H=\frac{5.5822kJ}{0.0396mole}[/tex]
[tex]\Delta H=1409.6kJ/mol=1.41\times 10^3kJ/mol[/tex]
Negative sign indicate the energy is released.
Therefore, the energy of combustion for one mole of ethylene is, [tex]-1.41\times 10^3kJ/mol[/tex]
