/sci/ - Science & Math

Total mass won't change. Bitches don't know 'bout Lavoisier.

don't you need the relative atomic masses to work this out?

Dunno. 4 grams of methane?

Maybe I'm wrong, but the matter used to make the CO2 and water should still have the same mass after being turned into the CO2 and water.

Of course, I'm probably incredibly wrong.

>>1029283
incorrect; mass is turned into energy because E = MC^2

Holy shit, are you 14?!

ok this is what i got so far

CH4 + O ---> CO2 + H20

Solution map:

step 1:
find molar mass of H20 to find mass produced in 9 grams of water.

step 2:
find molar mass of oxygen to find 16 grams of oxygen

>>1029278

No.
Lavoisier put a closed container on a scale. In the closed container was some sort of combustible and air. He managed to light it. The combustible burnt in the air contained in the closed container. The scale didn't move.

Hence his quote "Nothing is lost, nothing is created, everything is transforming".

http://en.wikipedia.org/wiki/Antoine_Lavoisier

4.00804661g

>>1029287
>incorrect; mass is turned into energy because E = MC^2
It's negligible in chemical reactions. It would be somewhere around 1% of mass is converted to energy for the most energetic chemical reactions.

>>1029287

We're speaking about a chemical reaction, in grams.

>>1029324
>The Tourist
What in the name of fuck....

>>1029339

>>1029328

I think 1% is way, way more than the actual value.

how did you find it out tourist?

I balanced my equation to
CH4 + 2O ---> CO2 + 2H2O

after that I am stuck I know i ned something like

Moles of CH4 to moles of Oxygen using my mole ratio but the problem is setting it up i always fail at that

>>1029371
First of all, fix your oxygen. It's diatomic.

>>1029386
Forgot to balance. Doesn't matter anyway.

>>1029386
Forgot to balance. Doesn't mater anyway. Needs more sage though. .

thanks for helping a lil girl out guys i am working on it now

Really, just use conservation of mass. It's as simple as that.

>>1029419
OMG LIL GIRL LMAO OMG xDDDD

8 GRAMS

If you get 0.25 mol of CO2, then you have used 0.25 mol of CH4.
0.25 * (12+4) = 8grams

Balance equation, convert mass to moles, use stoichiometric coefficients. Fucking simple.

It's actually 8 grams. Fuck. Doing chemistry high on coke isn't the best idea.

CH4 + O2 ---> CO2 + 2H20

ok guys i attempted to set it up this is how my teacher taught me

(9gH2O ) (1 mole of 2H2O) ( 11 grams of CO2)
--------------------- -------------------------
19.0153 g/mol 44.0096 g/mol

am i doing it right? i think something is missing sorry i am not so smart :(

>>1029546
1) Your equation still isn't balanced correctly.
2) The molar mass of water is 18.02

CH4 + O > CO2 + H20

1C 1C
4H 3O
1O 2H

balancing equation
CH4 + 3O > CO2 + 2H2O
1C 1C
4H 3O
3O 4H from ( 2H2 = 2x2)

is it balanced now? and I got 19.02 because of the 2HO2, am not supposed to do this? if so whats the point of balancing the equation? sorry :(

lol the tourist browses /sci/ too

>>1029650

You can't just put "O" like this. Oxygen is found in the form of dioxygen, a molecule with two oxygen atoms, hence the O2.

CH4 + 2O2 -> CO2 + 2H2O

ITT: high school kids who have passed chem 1 showing off to kids still in chem 1

>>1029807

>Has never taken chem in uni

ahh i see now thank you guys i am starting to get the hang of it, yes i am that slow :)

Then again, the not-fucking-with-equations way (also, the "I understood how the world works way") is :
9+11 = 20g of matter before
20-16 = 4g of methan missing to make 20g of matter before.

>>1029900

One of those "before" in actually an "after". True story.

YOU FUCKING HOMOS
YOU CANNOT USE MASS IN CHEMISTRY, CONVERT TO MOLES

IT IS 8 GRAMS

YES I STUDY CHEMISTRY IN UNIVERSITY

THIS

>>1029493
>>1029493
>>1029493
>>1029493
>>1029493
>>1029493
>>1029493
>>1029493

>>1029290
im 15, and im not OP

CH4 + 2O2 -> CO2 + 2H2O

H2O = 18g/mol
CO2 = 44g/mol
CH4 = 16g/mol
O2 = 32g/mol

You have 11g of CO2 in the end. That's 0.25mol.
The equation says you have as much moles of CO2 in the end than you had moles of CH4 before.
So you had 0.25mol of CH4.
0.25*16 = 4 grams.
You can verify this in different ways.

Also, the mass thing is the simpler way.
Don't listen to people that say anything else.

thank you so much guys i finally understand i wouldn't have done it without you and yes i am 14, sorry for being slow :) lov you all <3

How many /sci/entists does it take to solve a 9th grade chemistry problem? Too many.

Also, needs more sage.

i am 14 i tried to put my email there but it showed it haha not that i care but i am scared too lol i am 14 and been to /b/ that thing corrupted me :(

thanks >>1030061 your answer did make sence

this is how i did it

Total mass before and after the reaction should be nearly the same. Different bonds will lead to a difference in mass, but this change is far too small to be measurable on the weight-scale used in the question.
The products weigh 9+11 grams, and the oxygen weighs 16 grams. So the methane must weigh 4 grams.

>>1029278
That depends on how accurate you want it. If we're talking grams it doesn't matter. But on a smaller scale (or with greater accuracy) you would need to take into account the mass lost when making different, stronger bonds.

>>1029301
Oxygen is a BrINClHOF element (diatomic molecule)
so... it's O2 in the equation. not O.

>>1031144

yes i seem to have a trouble with that like
lets say why you read H2O as 2H and 1 O
but sometimes you have 2O when you balance the equation lets say, and this confuse me haha guess i am not that smart

>>1031757
That is correct; you are not.
Can we start saging this now?

>>1031772 I am sorry I don't know how, I input my name there and if i put my email, it shows it, how do i prevent this. sorry i am only 14 =/

im 12 and what is this?