I'm using the equation c3H8 + 5O2 yields 3 CO2 + 4H2O + 2220 kJ to figure out how many moles of O2 will be needed to produce 3450 kJ of the above reaction. I know this involves a proportion, but I have no idea what to write. Can you show me this proportion and I'll figure it out? Thanks for your explanation.
Is the answer 7.7 moles then?
I get 7.770 mols O2 and since you are allowed 4 significant figures I would use all of them.
Certainly! In order to find out how many moles of O2 are needed to produce 3450 kJ of the reaction, you can set up a proportion between the energy produced (kJ) and the number of moles of O2.
Let's start by setting up the proportion using the given equation:
c3H8 + 5O2 ⟶ 3CO2 + 4H2O + 2220 kJ
From the balanced equation, we can see that for every 5 moles of O2, 2220 kJ of energy is produced. This gives us the first part of the proportion: 5 moles of O2 = 2220 kJ.
Now, we can write the second part of the proportion using the unknown number of moles of O2 (let's call it x) and the desired energy of 3450 kJ: x moles of O2 = 3450 kJ.
Combining both parts, we get the proportion:
5 moles of O2 / 2220 kJ = x moles of O2 / 3450 kJ
To solve for x, we can cross-multiply and solve for x:
5 moles of O2 * 3450 kJ = x moles of O2 * 2220 kJ
Then, divide both sides by 2220 kJ:
(5 moles of O2 * 3450 kJ) / 2220 kJ = x moles of O2
Simplifying the equation further:
17250 kJ / 2220 kJ = x moles of O2
x moles of O2 ≈ 7.77 moles
Therefore, approximately 7.77 moles of O2 will be needed to produce 3450 kJ of energy in the given reaction.
3450/2220=Moles/5
solve for moles O2. Study the proportion, and make certain you know why it is correct.