Respuesta :
Explanation:
(a) Â Here, the assumption is that complete combustion of carbon is taking place. This means that there is no CO formation
Reaction equation when carbon is burning is as follows.
       [tex]C + O_{2} \rightarrow CO_{2}[/tex]
Molar mass of C = 12 kg/kmol
Molar mass of [tex]CO_{2}[/tex] = 44 kg/kmol
Hence, according to the stoichiometry,
1 Kmol of C reacted = 1 kmol of [tex]CO_{2}[/tex] produced
Therefore, 12 kg of C reacted = 44 kg [tex]CO_{2}[/tex] produced
It is given that coal contains 50 mass % Carbon
So, 1 kg of coal contains (0.50 × 1)kg Carbon
      Carbon in 1 kg Coal = 1 × 0.5 = 0.5 kg
As per the stoichiometry,
12 kg of C reacted = 44 kg [tex]CO_{2}[/tex] produced
0.5 kg of C reacted = x kg [tex]CO_{2}[/tex] produced
Therefore, value of x can be calculated as follows.
          x = [tex]\frac{\text{44 kg of CO_{2} produced} \times \text{0.5 kg of C reacted}}{\text{12 kg of C reacted}}[/tex]
            = 1.83 kg
This means that amount of [tex]CO_{2}[/tex] released is 1.83 kg.
(b) Â It is assumed that coal contains 50 mass % carbon and 1 kg of coal burnt.
Since, it is given that energy density of coal is 24 Mj and efficiency of the power plant is 30%.
After burning 1 kg of coal amount of energy released = 24 Mj
Amount of energy converted to electricity = [tex]24 Mj \times 0.3[/tex] = 7.2 Mj
It is calculated that amount of [tex]CO_{2}[/tex] released per 1 kg of coal = 1.83 kg
Therefore, calculate the amount of [tex]CO_{2}[/tex] released in kg/Mj as follows.
    amount of [tex]CO_{2}[/tex] released in kg/Mj = [tex]\frac{\text{Amount of CO_{2} released in kg}}{\text{amount of energy converted to electricity}}[/tex]    Â
            = [tex]\frac{1.83 kg}{7.2 mJ}[/tex]
            = 0.2541 kg/Mj
Hence, the production of [tex]CO_{2}[/tex] in kg/MJ is 0.2541 kg/Mj.
