How to Balance C8H18 + O2 = CO2 + H2O: Octane Combustion Reaction

In order to balance C8H18 + O2 = CO2 + H2O you'll need to watch out for two things. Visit www.Breslyn.org for video guides on balancing equations and more!
First, be sure to count all of C, H, and O atoms on each side of the chemical equation. Once you know how many of each type of atom you have you can only change the coefficients (the numbers in front of atoms or compounds) in order to balance the equation.
Be careful when counting the Oxygen atoms on the product side of the equation. Don't forget the O in H2O!
Drawing/writing done in Adobe Illustrator 6.0. Screen capture done with Camtasia Studio 4.0. Done on a Microsoft Surface Pro 3.

[@Carmenesquivi]

Thank you for this, I'm currently taking chem and couldn't understand balancing equations. You are awesome on explaining them. Thanks a lot for this video.

[@wbreslyn]

Glad I could help with balancing, it's used a lot in chemistry! --- Dr. B
Oh - and as you move on from balancing this site I created might be helpful...
www.breslyn.org/chemistry/stoich/

[@kaydencelai3597]

Thank you so much, this REALLY helped me on my homework

[@wbreslyn]

Good to hear! --- Dr. B

[@s.claire17]

Helped me with my test😂

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@@s.claire17 THIS IS MEE !!😭😭😂

[@tanushreehaveri9662]

Helpful to do my homework too....

[@kiransagoo4522]

Same

[@InflowInflowTopic]

you are a legend i literally learned this instantly when you explained this rather than my teacher

[@amberbenton7658]

Thank you Dr. B for making chemistry easier to learn with all your helpful tutorials. Greatly appreciated!!!

[@wbreslyn]

You're very welcome!

[@jilliangerig1035]

I spent so much time trying to figure this problem out and you explained everything in a very helpful and concise way that I actually understood! Thank you!

[@wbreslyn]

You're welcome!

[@kaenriyah]

thank you for this ! your video made it all so much clearer to me :)

[@notmerom9145]

This really helped me. Thanks.

[@Eccentric312]

Thanks so much. I didnt wanna watch a 10 min video, and this was sooo clear!! Been struggling with balancing this equation for the past, God knows how long.

[@wbreslyn]

Yeah, this one is sort of a pain! Glad I could help. --- Dr. B

[@Gob.]

The way you explain this and speak is so relaxing, thank you so much.

[@wbreslyn]

You're very welcome!

[@taengukim1295]

this channel is a life saver

[@dheerajreddy2987]

Thank you Mr B this helped me a lot

[@MsFrog-cm7pi]

Thank youu so muchh!! U explain better than everybody else

[@derinderin9200]

Dr. B the savior of my grades, thanks you so much

[@erinaqose5431]

This helped me so much. Thank you!

[@dylancanarvis]

i very glad that you make these videos, they have made the last two days easy haha

[@wbreslyn]

Glad you like them!

[@roohinkukreja1136]

Thank you, this was really helpful.

[@greyson870]

these videos are so helpful! Thank you dr B!

[@wbreslyn]

Glad you like them!

[@sunmaw108]

This was a tough one, thank you very much Mr. B!

[@wbreslyn]

You're very welcome!

[@chugs6817]

When you multiply the all coefficients by 2, is that changing 1 mole of octane to 2 moles?

[@epicsblue5445]

Thank you for posting so much videos!

[@wbreslyn]

No problem!!

[@5tarkay18]

Thank you so much this really helped with my work🙂

[@lourdesmartinez9319]

how can we know or see what kind of reaction it will have?

[@johnbrackston1203]

You are fantastic!

[@petergriffin5539]

Thanks you actually saved me in here because the word problem version of this looks so daunting to me

[@wbreslyn]

Glad I can help!

[@artifxcial6603]

this guy is a legend

[@tomassturla1183]

One question, to this balanced equation, what is the conservation of mass? I'm in class and I need the answer please, I'm from Argentina

[@yeyeyeueuwueyeyeue]

you saved me thank you so much!!

[@abritutterow3513]

thanks for helping me on my quiz

[@GabrielMatos-lz1xy]

god bless your soul Dr. B

[@wiseshadow8403]

Best teacher

[@haotianzhao9003]

very helpful！

[@rionm9111]

thanks man

[@jeremyc8372]

Why do you need to divide the 25 by 2 when balancing the oxygen?

[@pOptArtKittyyy]

Because the fraction is practically 12.5 and no whole numbers multiplied by 2 are 25

[@soniakom670]

Thank you so much, this really helpsd me in doing my home work and ur explaining is so good n, thanks for the video ❤❤❤❤

[@wbreslyn]

My pleasure 😊

[@sorupakagnaneshwar8205]

Thank you so much, this question is is so difficult , after watching ur video I really felt so easy, it really helped me a lot.

[@sorupakagnaneshwar8205]

Tq Dr. B

[@Pavi974]

Thank you so so so so much sir

[@eagleheart1634]

This man is saving my grade

[@zendykun1938]

How do I know what are going to be the products?

[@I_loveNoodles]

in some equations it's easy to predict the product like in single/double displacement the stronger and the most reactive replace the weaker and less reactive. also in combustion reactions the products will be H20+CO2. burning metal carbonate the products will be metal oxide + CO2. hope that helped :))

[@productivityqueen]

Can we write 12.5 O2 instead of 25/2

[@Lombreee]

THANK YOU

[@Paco-sg9je]

Hello Dr. B I was wondering if you could simply just simplify this and write it as C8H18 + 12.5O2 = 8CO2 + 9H2O and not haveing to double scale everything for example how you made 2C8H18 + 25O2 = 16CO2 + 18H2O

[@wbreslyn]

As a chemist I would probably go with the simplified version since I'm really only interested in the ratio of coefficients. So you are correct. But some teachers, and makers of multiple choice tests, really seem to like whole numbers. So I suppose it depends on why you are balancing in the first place.

[@leilonicmiranda7763]

Now I understand how to Balance! but what factors would increase the speed of this reaction? and how does this work with the law of conservation of matter? I'm so lost on that.

[@yahiralvarez9807]

You’re conserving matter on both sides by balancing

[@jeremiahjoe8283]

Great video

[@wbreslyn]

Thanks! --- Dr. B

[@saa-123]

Thank you

[@girlwithlove5827]

Are the subscripts not going to change since u put a two in front of it

[@wbreslyn]

Right, the subscripts don't change when you balance chemical equations. Very important and something people often confuse!
Take a look at this:
th-cam.com/video/wGNgY2XoYPs/w-d-xo.html
--- Dr B

[@sarahdadito]

you save my life thank you sir

[@wbreslyn]

Glad I could help with C8H18! --- Dr. B

[@aa_le_lo_la]

Thank you 😊😊

[@vivekgaming219]

Thank you so much sir.this video is really very helpful for me

[@wbreslyn]

Most welcome!

[@gauravchauhan199]

Thanks Sir 😀

[@Alfacartoonyt]

Thanks sir for help

[@shivgamers4246]

sir, where are you from

[@azalyeamitsuka7271]

thank you dis help meeeeee

[@delaunte7]

where did you get the 25/2 from

[@notmerom9145]

remember that in chemical equation, you just get any number for your chemical equation to be balanced.

[@13rahim77]

Since there are only 2 oxygens on the left side, if we multipy half of 25 by 2 we get 25

[@yixuan_aa]

tysm :)

[@pour9989]

thank you so much !

[@wbreslyn]

You are most welcome! -- Dr. B

[@enesozbek6236]

Thx man!

[@wbreslyn]

No problem! --- Dr. B

[@raiinbery1036]

You made it like pice of cake for me thank💜💜👌🏾

[@juliane7377]

How did you know the exact equation i needed

[@wbreslyn]

That is a good question!

[@grovelnd]

Thank you!!!

[@wbreslyn]

Glad I could help with the combustion of octane! --- Dr. B

[@joseemmanuelmontano7223]

Thank you!!!!!!!!!!

[@wbreslyn]

No problem, glad I could help! --- Dr. B

[@maazouzhocine4856]

Thank you so much❤️

[@wbreslyn]

You’re welcome 😊

[@musa4747]

Wish I had TH-cam when i was growing up. Would've been a master at maths.

[@wbreslyn]

Agreed!

[@shathaagoha5278]

Thank you so much this helped me on my homework

[@wbreslyn]

Excellent!

[@random_girl1249]

Thank you so much! This is really helpful, although I was wondering how this equation would be balanced if there was limited oxygen, I've been trying to work it out, but I just can't seem to get the numbers right (C8H18 + O2 -> CO + H2O)

[@wbreslyn]

A bit late here, but this is a technique you can use for challenging equations and then work backwards to understand:
www.webqc.org/balance.php?reaction=C8H18%2BO2%3DCO%2BH20

[@random_girl1249]

@@wbreslyn Thank you!!

[@IvanMTG1]

wonderful explanation of a non-whole number balancing!

[@pet.err42]

I did it ! I have the same answer but without multiplying hte whole by 2, idk i just used brain and did it, cuz i did not know that we can multiply all of it by 2 !!

[@BabaSphere]

Fantastic

[@wbreslyn]

Thanks! --- Dr. B

[@Zincat550]

I am doing my homework coaching center I understand that thanks for helping us

[@wbreslyn]

Happy to help!

[@Phoenix_BD]

Have done this more then 100 times, feel so stupid forgeting this simple technique hahahah.

[@regor_4683]

Thx

[@Cb54109]

which are the reactants in the equation

[@wbreslyn]

The ones you start with (C8H18 + O2). The products are the ones produced.

[@matthewso1315]

Thanks

[@wbreslyn]

No problem! --- Dr. B

[@tasingsingkom3775]

Nice video sir

[@wbreslyn]

Thanks! --- Dr. B

[@michaelsnideruruenarivera5714]

muchas gracias me sirvió de mucho soy de colombia :)

[@wbreslyn]

De nada!

[@phsyonixmadao2788]

saved my ass man. Thanks

[@FosterUN]

What type of reaction is this?

[@sanafuadd]

Combustion

[@wbreslyn]

Yep!

[@hanazedan6281]

I want to equalize the octane combustion when the air is less than the theoretical amount

[@wbreslyn]

Sounds like a limiting reagent problem. This page might help:
www.breslyn.org/chemistry/stoich/

[@ilovedonuts444]

Thank u

[@wbreslyn]

No problem

[@foreveralxndr]

thanks

[@wbreslyn]

No problem! --- Dr. B

[@Pavani_2579]

Why do we have to divide with 2!!!!!

[@hannahfeshoh9865]

ily dad

[@mrpleasewrok6255]

5 years later and this question came up on the GCSE chem paper 2 edexcel exam ahhhhh

[@wbreslyn]

I was a bit early with this video!

[@jonathanriosnavarro1899]

i love you

[@ibandr2749]

me 2

[@anolive7535]

Shouldn't it be 50 oxygen? Because with the doubled numbers the products have a total of 50 oxygen (16x2=32, 18x1=18, 32+18=50).

[@huizylove]

I thought the same thing but check that the O in the left has a under script of 2

[@pOptArtKittyyy]

THANK YOU-! I was confused cuz he used a fraction and we have to use a whole number

[@pOptArtKittyyy]

@@huizylove the total at the end is 50 but that subscripted O would be 25

[@oceansaraf]

I actually owe my life to you

[@wbreslyn]

Glad I could help! --- Dr. B

[@alexahenriquez1909]

I Love u

[@mohdjamal4857]

Multiply 25 ×2 ...its more than 25 in the right side🤔 balancing is really hard😫😣

[@wbreslyn]

This might help:
th-cam.com/video/PrWtXYK8tXM/w-d-xo.html
--- Dr. B

[@jakesimpson6365]

But there’s way more than 25 Oxygens on the right side wtf

[@wbreslyn]

Your are right! Remember that you have 25 O2 molecules. So that's a total of 50 Oxygen (O) atoms. --- Dr. B

[@theearnmoreyouagainmoreres8250]

Carbon copy nothing is what it seems

[@MamtaYadav-gc1nr]

This is so late

[@jyotigarg8034]

Is this question of class 10th???

[@jyotigarg8034]

Anyone pls tell

[@love2fur]

sorry i didn't watch the tutorial, i just skip to the answer. BUt thanks

[@wbreslyn]

No problem 👍

[@izybunny1999]

So.. I could do that

[@wbreslyn]

Excellent!

[@scarMinton]

H

[@mandlaklaas4103]

im hating on this because im a sore loser and i got this wrong yet the answer is simple

[@wbreslyn]

That has often been my experience with chemistry as well!

[@ryanlindahl1353]

wrong

[@wbreslyn]

Check this:
socratic.org/questions/c8h18-o2-co2-h20
--- Dr. B

[@Specticle_luchano]

Thank you sir 😊

[@wbreslyn]

You're welcome!

[@anshitagosain5103]

Thank you

[@wbreslyn]

You're welcome!