Chemistry question...number of moles and mass etc...?

Question

A pure sample of iron (III) sulfide, Fe2S3, has a mass of 8.160g
a) How many moles of Fe2S3 are in the sample?

b) What number of moles of iron (III) ions are present?

c) What number of moles of sulfide ions are present?

d) What maximum mass of iron could be obtained from the sample?

Please help me! I have been working on these questions for about 2 and a half hours. I have been going through my chemistry textbook and booklets. I think I have the answer to a but I have no idea how to find the number of moles of iron (III) ions. I need to know that to answer c. In part d, how do I find the answer? Please help me and show me the correct processes (clear working) involved before the answers. Thankyou chemistry wizzes.

Answer 1

a) iron (III) sulfide has a molar mass of 207.892g/mole
The number of moles of iron (III) sulfide = 8.160/207.892g = 0.0393 moles.

b) there are 2*0.0393=0.0786 moles of iron (III) ions present.

c) There are 3* 0.0393= 0.1179 moles of sulfide ions present.

d) This is simply the number of moles of iron present in the sample. There are 2*0.0393 = 0.0786 moles of iron present. The molar mass of iron is 55.847g/mole. The mass of iron present is 55.847* 0.0786 = 4.384g

Answer 2

a) The number of moles of Fe2S3 = 8.160/207.9 = 0.0392mol

b) The moles of iron III present is 0.03925 x 2 = 0.07849mol

c) The moles of sulfide ions present is 0.03925 x 3 =0.1177mol

d) Mass of iron III = 0.07849mol x 55.85g/mol = 4.384g
Using 4 sig figs.

Answer 3

basically evaluate each thing as a ratio, look at what the instruments of your undemanding is, and look on the instruments of what you want to understand. Now all it truly is necessary a set of ratios that cancel out and artwork like a street map for your answer. I wont do it out for you, yet listed decrease than are some ratios i'd discover effective: -avogadro's huge form: a million mole in line with 6.022x10^23 atoms -molecular weight of water (16+2(a million)) = 18grams of water in line with mole of water -a million oxygen in line with water -2 hydrogen in line with water