Question

Last study guide question! I have sorted worked through some it but want to make sure...

How many grams of C2H5OH are used up when 6.25 grams of O2 react according to the same equation?

C2H5OH + 3O2 = 2CO2+ 3H2O

Answer 1

I know the weight is 276.408

Answer 2

and the molar mass is 46.068

Answer 3

the moles are 6. If you could just share the equation, I want to work through it by myself.

Answer 4

Convert 6.25 gram O2 to moles, check the mole ratio
calculate the amount of moles C2H5OH that is needed to react
convert that to gram :)

Answer 5

i multiply 6.25 by 6.023x10^23 to get moles correct?

Answer 6

Mass to mole

Answer 7

You got the amount of moles \(\sf\large O_2\)?

Answer 8

0.39064941558847 i dont think thats right lol

Answer 9

because the molar mass of oxygen is 15.999

Answer 10

the molecular mass of \(\sf O_2\) is 31.998 g/mol (15.999*2)

So \(\sf\large\dfrac{6.25}{31.998}=0.1953 ~mol\)

Answer 11

oh because you have 02 so 15.999x2=31.998

Answer 12

Yes :)
Now we have to calculate how many moles of ethanol is used.

Answer 13

ahhh the cross table :) 0.1953x1/3= 0.0651

Answer 14

calculating those moles to weight we get =2.999055444

Answer 15

then subtracting 6.25-2.999055444= 3.25094456?

Answer 16

yea 0.0651*46.07 =2.999 :) great job

Answer 17

gram sorry

Answer 18

oh 2.999 is my answer?

Answer 19

yes :)

Answer 20

2.999 gram ethanol reacts with 6.25 gram oxygen

Answer 21

why do i always think these problems are much harder then they really are hahaha

Answer 22

Yea when you practice some of these questions, you'll realize that it's actually very easy :)
Save the mol conversions diagram, it can be very helpful for these questions.

Answer 23

i saved it to my desktop. it really clears it up. Thanks a lot once again!