stoichiometry question..?

Question

how do you convert moles to grams . and grams to moles??
whats the formula??


i have a problem how do i solve it??

iron(IV) sulfide is burned in pure oxygen to yield iron(III) oxide and sulfur dioxide. if 0.012mol iron(III) oxide was produced, calculate the number of grams of iron (IV) sulfide used in the reaction.




little help please.. thanks..

Answer 1

One mole = the atomic weight of an element or compound in grams.

One mole of carbon = 12 grams, the atomic weight of carbon is twelve.

The atomic weight of oxygen is 16, one mole of oxygen = 16 grams.

So you need to know the atomic weight of the elements and compounds you are working with. Always try to look up atomic weights in a table or a reference.

iron (iv) sulfide is FeS2, pyrite (fool's gold), the molecular weight = 119.98

iron (iii) oxide is Fe2O3, the molecular weight = 159.69

sulfur dioxide is SO2

pure oxygen is O2

The overall reaction is:

FeS2 + O2 ---> Fe2O3 + SO2

This reaction is not "balanced", because you need the same number of atoms for each element on the left as on the right.

It does show, however, that to make one molecule of Fe2O3 requires two molecules of FeS2. And that is all we need to know to solve the problem.

To form 0.012 moles of Fe2O3, you need 2 x 0.012 = 0.024
moles of FeS2.

0.024 moles of FeS2 x 119.98 grams/mole = 2.88 grams of iron (iv) sulfide.

Answer 2

First of all, you need to write down the formulas of the compounds that have a role in the reaction.

iron(IV) sulfide = FeS2
pure oxygen = O2
iron(III) oxide = Fe
sulfur dioxide = SO2

This is the reaction balanced:

4 FeS2(s) + 11 O2 (g) ====> 2 Fe2O3(s) + 8 SO2(g)

if 0.012mol iron(III) oxide was produced, calculate the number of grams of iron (IV) sulfide used in the reaction.

From the balanced formula, N number of moles of Fe2O3 derive from 2N moles of FeS2, therefore you need 0.024 moles of iron (IV) sulfide.

Now you need to convert number of moles into grams. You need the molecular weight:
MW (FeS2) = 120 g/mol
Therefore 0.024 moles correspond to :
0.024 x 120 = 2.88 grams

Answer 3

The molecular weight (MW) of any element or compound is given in grams per mole (g/mole).

If you have grams, divide by the MW to get moles.
If you have moles, multiply by the MW to get grams.

To answer your question, 1) balance the equation, 2) determine the moles of Iron sulfide used to get the moles of iron oxide 3) convert the moles to grams.

Answer 4

On the periodic table, there is a # in grams on each element (for Hydrogen, it's the 1.008). If it is not 1 of these diatomics:
Hydrogen
Oxygen
Nitrogen
Chlorine
Bromine
Iodine
Fluorine
That number will be the grams per mole. For the 7 diatomic I've included above, multipaly that number by 2 (if it's alone and not in a compound - if it is in a compound, it's just x1). For compounds, just add each element's mass together - carry the subscripts out too.

Answer 5

First you need to write a balanced equation.

FeS2 + O2 --> Fe2O3 + SO2

Balanced, this becomes

4FeS2 + 11O2 --> 2Fe2O3 + 8SO2

Since the ratio of Fe2O3 to FeS2 is 1:2, 0.012 mol Fe2O3 is produced from 0.024 mol FeS2.

1 mol of mol FeS2 has a mass of 56 + 64 grams = 120 grams.

0.024 mol is 2.88 grams.

Answer 6

Look up (or calculate) the molecular mass; note the units are g/mole. If you know the moles, multiply by the molecular mass to get grams. If you know the grams, divide to get moles.

Answer 7

what number moles of nitrogen and hydrogen are required to make one mole of ammonia, NH3? equation N2 + 3H2 = 2NH3 so dividing by using 2 to get one mole of NH3 supplies a million/2 mole of N2 and 3/2 mole of H2