Question

if you started with 300 g of fe2o3 and 84 g of co which would be the limiting reactant

Answer 1

What is the reaction?

Answer 2

The general idea is to use stoichiometry for each compound to find the amount of product produced separately.

Answer 3

Which ever one produces the smallest amount of product is limiting.

Answer 4

soo how would i do that i dont get this problem

Answer 5

can u work it out for me pleaseee

Answer 6

You need a reaction. Are you given a reaction?

Answer 7

yea the reactant is Fe2O3+3CO _____ 2fe+3Co2

Answer 8

Ok, and it is already balanced. Great! :)

Answer 9

yea the only good thing abt the problem lol

Answer 10

haha

Answer 11

Do you know how to do stoichiometry?

Answer 12

yea thats what this chaper is about but im a lil shakey on it :(

Answer 13

Ok, so in this problem you will need to do 2 stoichiometry problems.

Answer 14

ok

Answer 15

Start with one of your reactants, convert the grams to moles, then the moles of the reactant to the moles of product using the mole ratio in the reaction.

Answer 16

Since you have 2 products you can pick either one to base your calculations on. Just be consistent.

Answer 17

ok so how would i set that up

Answer 18

200 g of Fe2O3 * (1 mol/ MM of Fe2O3) = ? moles of Fe2O3

Answer 19

can you find the molar mass (MM) of Fe2O3?

Answer 20

nope

Answer 21

do i have to find the atomic mass of them

Answer 22

Right. You get it from your periodic table. 2*atomic mass of Fe + 3*atomic mass of O

Answer 23

ok i understand that part

Answer 24

ok so when i add that up i get 159.7

Answer 25

Great! So, how many moles of Fe2O3 do we have?

Answer 26

so take 159.7x 200

Answer 27

i mean 300

Answer 28

or divide it

Answer 29

Not quite. So we had 300 g Fe2O3. We want moles and we have 159.7 grams/1 mol. So, to cancel out the grams and leave moles we do
300 g *(1 mol/159.7 g) = 1.879 moles Fe2O3

Answer 30

Make sense?

Answer 31

yes that makes scence but im saying like what do i do with that number whats the next step

Answer 32

i understand how u got 1.879 so what do i do now

Answer 33

We need to find how much product each reactant produces. So, we can use the coefficients in the reaction to convert from moles of a product to moles of a reactant.

Answer 34

We can find the moles of either product. We just need to compare at the end.

Answer 35

ok

Answer 36

So, 1.879 moles of Fe2O3 * 2 moles of Fe/1 mole of Fe2O3 = 3.758 moles of Fe

Answer 37

So, we figured out how many moles of Fe we can produce from the amount of Fe2O3 we had. Now we need to figure out how many moles of Fe we can produce from the amount of CO we have.

Answer 38

Whichever one produces less will run out first and will be the limiting reactant.

Answer 39

ok

Answer 40

Can you calculate the moles of Fe that can be produced from the 84g of CO?

Answer 41

so just do what we just did

Answer 42

Yup, using CO's molar mass and coefficient.

Answer 43

so find atomic mass for c and o and add them then divide it by 84

Answer 44

84 divided by what you said.

Answer 45

so 84 divided by 28.01

Answer 46

Yup

Answer 47

so it will cancel out the grams so it will b in moles n i get 2.998

Answer 48

so the fe203 is the limiting reaction

Answer 49

Sweet. :)

Answer 50

No wait.

Answer 51

You aren't done yet. You only found the moles of CO. You need to compare the moles of Fe.

Answer 52

how

Answer 53

Using the reaction coefficients. 3 moles of CO = 2 moles of Fe

Answer 54

like a ratio

Answer 55

Yup.

Answer 56

Thanks @wolfe8 :)

Answer 57

Convert to moles of Fe

Answer 58

omg ughhh i thought we were done

Answer 59

so what am i suppose to conver what numbers with what

Answer 60

Last step :) You can do it!

Answer 61

2.998 moles of CO * (2 moles of Fe/3 moles of CO) =

Answer 62

=1.998

Answer 63

Awesome! So, now we can compare moles of Fe

Answer 64

ok

Answer 65

Because we have calculated moles of Fe using each of our reactants.

Answer 66

oh

Answer 67

It was 1.998 moles of Fe, by the way.

Answer 68

so thats the final answer right

Answer 69

So, which reactant is the limiting reactant (runs out first)?

Answer 70

No, we need to compare the the moles of Fe produced from each reactant. The reactant that produces less product is the limiting reactant.

Answer 71

ok so Fe runs out first

Answer 72

Fe is a product. It can't run out. It is being produced.

Answer 73

Fe2O3 and CO are your reactants.

Answer 74

We calculated that we could produce 3.76 moles of Fe from the amount of Fe2O3 wee started with.

Answer 75

And 1.998 moles of Fe from the amount of CO we started with.

Answer 76

ok so if i cant say its the fe or co then what can it be then

Answer 77

Your options are Fe2O3 or CO.

Answer 78

CO is the reactant that produces less product, so it is limiting.

Answer 79

ohhhh ok

Answer 80

I would suggest doing some review questions on conversions and stoichiometry. They will help you in the future.

Answer 81

ok thx are u like a chemistry teacher or something

Answer 82

I am a tutor. :)

Answer 83

ohh ur not in school

Answer 84

I have a bachelors degree in Chemical Engineering.

Answer 85

Nope. Not in school right now.

Answer 86

ohhh thats kool

Answer 87

Keep studying! You'll get it if you work at it:)

Answer 88

ok thx!!

Answer 89

No worries.

Answer 90

Welcome to OpenStudy!

Answer 91

If your question has been sufficiently answered, please award the answerer with a medal and close the question. Also, take a look at the code of conduct. Happy studies. :)

Answer 92

lol i did u have 2 medals now :)

Answer 93

haha, thanks!

Answer 94

The more the merrier :)

Answer 95

no thank u for helping me :)

Answer 96

yw