Using the equation:
2C2H6 + 7O2--> 4CO2 + 6H20
How may moles of 02 are needed to react with 4.0 mol of C2H6?
I think the answer is 14, because if you double the C2H6 to make 4.0 mol, then in the equation you will need to double the O2 to 14.
Is this correct?
That is absolutely correct and your reasoning is sound. But if the numbers didn't come out so even could you do it? Here is the way itis done for ALL problems. You use the coefficients.
4.0 mols C2H6 x (7 mols O2/2 mols C2H6) = 4.0 x (7/2) = 28/2 = 14 mols O2.
How do you know which numbers goes on top and which on the bottom? Look at the units. By placing O2 on the top and C2H6 on the bottom, the mols C2H6 cancel to leave mols O2 as the unit and that's what you want. If you put mols C2H6 on top and mols O2 on the bottom, the units for the answer will be (mols C2H6)^2/mols O2 and that isn't what you want. You want the final unit to be mols O2.
From the same equation as above, how many moles of CO2 are produced by the reaction of 21.0 mole of O2?
21 moles of O2 means that you would need to multiply 7O2 in the quay ion by 3, so 3 x 4CO2= 12CO2?
That is correct but check my response to this question posted separately. I would strongly suggest you do it through the coefficient process so you can do it easily if the numbers are not even multiples as they were in the previous problem or in this new one.
Well, you're certainly on the right track, but you might be multiplying a bit too much. Let's take a closer look at the balanced equation:
2C2H6 + 7O2 --> 4CO2 + 6H2O
The ratio in the equation tells us that for every 2 moles of C2H6, we need 7 moles of O2. So, since we have 4.0 moles of C2H6, we can set up a simple proportion to find the number of moles of O2 needed:
(4.0 mol C2H6 / 2 mol C2H6) = (x mol O2 / 7 mol O2)
Cross-multiplying and solving for x, we get:
x = (4.0 mol C2H6 * 7 mol O2) / 2 mol C2H6
Doing the math gives us x = 14 moles of O2. So, good job! Your answer of 14 moles is correct. Keep up the good work!
No, your answer is not correct. To determine the correct number of moles of O2 needed to react with 4.0 mol of C2H6, we can refer to the balanced chemical equation:
2C2H6 + 7O2 → 4CO2 + 6H2O
According to the balanced equation, we need 7 moles of O2 to react with 2 moles of C2H6. So, the ratio of O2 to C2H6 is 7:2.
To find the moles of O2 needed to react with 4.0 mol of C2H6, we can set up a proportion:
(7 mol O2 / 2 mol C2H6) = (x mol O2 / 4.0 mol C2H6)
Cross-multiplying and solving for x, we have:
2 * (x mol O2) = 7 * 4.0 mol O2
2x = 28.0
x = 28.0 / 2
x = 14.0 mol O2
So, you were correct in recognizing that the amount of C2H6 doubles, but the correct answer is 14.0 mol O2, not 14.