Calculate the standard cahnge in enthalpy for the combusation of coal/ Show the balnaced reaction. How does one get the balanced reaction of coal? Coal has many substances that make up its compsistion
You are quite right. The heating value of coal varies with type, from 15,000 to 27,000 kJ/kg for soft coals, reaching 31,000 for coke and 34,000 for anthracite. They may want you to use the heat of formation of Carbon (graphite). It is a poorly constructed question.
The balanced reaction is
C + O2 -> CO2
To determine the balanced reaction for the combustion of coal, we need to consider the general equation for the combustion of any hydrocarbon fuel. Coal is predominantly carbon (C) with small amounts of hydrogen (H) and other impurities. Let's assume our coal sample consists only of carbon (C).
The balanced equation for the combustion of carbon can be written as:
C(s) + O₂(g) → CO₂(g)
This equation indicates that carbon (in the solid state, denoted as C(s)) reacts with oxygen (in the gaseous state, denoted as O₂(g)) to produce carbon dioxide (CO₂) as the only combustion product.
To balance this equation, we need to ensure that the number of atoms of each element is the same on both sides of the equation. In this case, we have one carbon atom on the reactant side and one on the product side. However, there are two oxygen atoms in the oxygen molecule (O₂), so we need to balance the equation by placing a coefficient of 2 in front of CO₂:
C(s) + 2O₂(g) → 2CO₂(g)
This is the balanced equation for the combustion of carbon (or coal, assuming it only consists of carbon).
It's important to note that the composition of coal can vary, and it may contain other substances like hydrogen, sulfur, nitrogen, etc. To obtain a more accurate balanced equation, the composition of the specific coal sample needs to be known.
To determine the standard change in enthalpy for the combustion of coal, you would typically require the enthalpy values of the reactants and products involved, as well as any heat of formation values for the compounds. These values can be found in reference data like handbooks or online databases. Then, you can calculate the enthalpy change using the difference between the sum of the product enthalpies and the sum of the reactant enthalpies using the balanced equation.