consider the following equilibrum reaction:
2NO yield N2 + O2.
Take:delta H=-18.0KJ/M
To determine the heat of reaction using the given enthalpy change, we can start by understanding the basics of an equilibrium reaction and how to calculate the heat of reaction.
In this reaction, 2 moles of nitric oxide (NO) react to form 1 mole of molecular nitrogen (N2) and 1 mole of molecular oxygen (O2). The reaction is said to be at equilibrium.
The enthalpy change, ΔH, is given as -18.0 kJ/mol. It represents the heat released or absorbed during the reaction per mole of the reactants or products.
To calculate the heat of reaction, we need to determine the number of moles involved in the reaction.
In this case, we have 2 moles of NO reacting to produce 1 mole each of N2 and O2. Therefore, the heat of reaction, ΔH, will also be in terms of moles of the reactants and products.
Given that the ΔH is -18.0 kJ/mol, it means that for every 1 mole of NO that reacts, 18.0 kJ of heat is released.
If you want to determine the heat released or absorbed for a certain quantity of reactants, you can use the stoichiometry of the reaction. The stoichiometry tells us the ratio of reactants and products in the balanced equation.
For example, if we have 4 moles of NO, we can calculate the heat released using the following steps:
1. Determine the moles of NO:
Moles of NO = 4 moles
2. Calculate the expected moles of N2 and O2 produced:
Moles of N2 = (4 moles NO) / (2 moles NO) = 2 moles
Moles of O2 = (4 moles NO) / (2 moles NO) = 2 moles
3. Calculate the heat released or absorbed:
Heat released = (Moles of NO) x (ΔH)
Heat released = (4 moles) x (-18.0 kJ/mol) = -72.0 kJ
Therefore, if you have 4 moles of NO, the heat released or absorbed will be -72.0 kJ.
Remember to adjust the signs (+/-) of the heat based on whether the reaction is exothermic (releases heat) or endothermic (absorbs heat), as indicated by the given ΔH value. In this case, the negative sign (-) indicates that the reaction is exothermic, and heat is released.