Carbon monoxide reacts with oxygen to form carbon dioxide by the following reaction:
2CO2 + O2 yields 2CO2
Delta H for this reaction is -566 kJ/mol run. What is the delta H for CO?
1). +270 kJ/mol
2). -110 kJ/mol
3). +65 kJ/mol
4). -405 kJ/mol
5). -65 kJ/mol
6). -182 kJ/mol
7). +135 kJ/mol
there's no right ansswer
To find the delta H for CO in the given reaction, we can use the fact that the delta H value is additive.
The balanced equation for the reaction is:
2CO + O2 → 2CO2
Based on this equation, for every 2 moles of CO that react, 2 moles of CO2 are formed. Therefore, the delta H for this part of the reaction is also -566 kJ/mol.
Now, let's consider the balanced equation for the formation of CO:
C + 0.5O2 → CO
Based on this equation, 1 mole of CO is formed from 1 mole of O2. Since the delta H for the formation of CO2 is -566 kJ/mol, the delta H for the formation of CO will be the same but with opposite sign.
Therefore, the delta H for CO is +566 kJ/mol.
However, none of the given answer choices match this value. So, based on the given options, we cannot determine the correct delta H for CO.
To find the ΔH for CO, we can use the fact that the reaction we are given is the reverse of the reaction we need to find ΔH for.
The given reaction is:
2CO2 + O2 → 2CO
Since ΔH for the given reaction is -566 kJ/mol, it means that the ΔH for the reverse reaction (CO → CO2) is +566 kJ/mol.
Now, we need to find the ΔH for CO. To do this, we can multiply the ΔH for the reverse reaction by -1. This is because reversing a reaction reverses the sign of ΔH.
Therefore, the ΔH for CO is -(+566 kJ/mol) = -566 kJ/mol.
From the options provided:
1) +270 kJ/mol
2) -110 kJ/mol
3) +65 kJ/mol
4) -405 kJ/mol
5) -65 kJ/mol
6) -182 kJ/mol
7) +135 kJ/mol
The correct answer is option 4) -405 kJ/mol, as it matches the ΔH for CO.
dHrxn = (n*dHf products) - (n*dHf reactants)
dHrxn = (2*dHf CO2) - (2*dHf CO)
-566 = 2*-393.5)-(2x)
Solve for x. I picked up the = -393.5 kJ/mol from tables in my text.