Question

How many liters of water vapor can be produced if 8.9 liters of methane gas (CH4) are combusted, if all measurements are taken at the same temperature and pressure? Show all of the work used to solve this problem.

CH4 (g) + 2 O2 (g) ---> CO2 (g) + 2 H2O (g)

Answer 1

So, this one is a little different but it is still similar.

Answer 2

Still the same formula right?

Answer 3

Yup, but this time you have to use it twice :)

Answer 4

Can you help me get started?

Answer 5

Sure. First we need to use the 8.9 L of methane in the ideal gas formula to find moles of methane.

Answer 6

Since it says same temp and pressure we can use any temp and pressure as long as we are consistent.

Answer 7

Ok so P=1 V=8.9 T=273

Answer 8

Right. And R?

Answer 9

R=0.0821

Answer 10

Lookin good :)

Answer 11

1*8.9=n*.0821*273

Answer 12

N=2.52

Answer 13

That's not what I get...

Answer 14

8.9/(.082*273)=n

Answer 15

N=.397

Answer 16

That's what I get :)

Answer 17

so we do it once more?

Answer 18

Not yet. What is the unit of .397?

Answer 19

CH4?

Answer 20

Right. 0.397 mol CH4

Answer 21

ok

Answer 22

Can you use that to get the moles of water?

Answer 23

Im lost here

Answer 24

You can use the molar ratio of the reaction to convert from one type of mole to another,

Answer 25

0.397 mol CH4 (2 mol H2O/1 mol CH4) = ?

Answer 26

.1985

Answer 27

How did you get that?

Answer 28

divided .397 by two

Answer 29

But the 2 is in the numerator.

Answer 30

When the 2 is in the numerator you multiply.

Answer 31

When the 2 is in the denominator, you divide.

Answer 32

ohh ok so if it would be 1/2 you would divide ok i got it sorry

Answer 33

You got it! :)

Answer 34

No worries

Answer 35

.794

Answer 36

Sweet

Answer 37

so this would be our new n

Answer 38

Right!

Answer 39

P=1 n=794 R=0.0821 T=273 and we have to find V

Answer 40

Yup, but don't forget the decimal again :)

Answer 41

.794

Answer 42

there you go :)

Answer 43

17.796L of H20

Answer 44

Good job!

Answer 45

Ok i just need one more

Answer 46

I can try :)