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) MW Fe2S3 is 2*55.847 + 3*32.066 or 207.89 g/mol, so there are 8.160g/207.89g/mol or 0.0392 moles.
b) There are 2 moles of Fe3+ for every mole of Fe2S3, or 0.0784 moles.
c) There are 3 moles of S2- for every mole of Fe2S3, or 0.118 moles.
d) The mass percentage of iron in the compound is 2*55.847/207.89 or 53.73%. So, of the 8.160g, 4.384 g of iron can be obtained.

Answer 2

Divide 8.16 grams by the molecular weight of Fe2S3(find the weight of Fe on the periodic table, multiply is by 2 and find S on the periodic table and multiply by 3) to get moles. For every 1 mole of Fe2S3, there are 2 moles of Fe and 3 moles of S. So, whatever the answer is for part a, use it for part b and c. So if there are .05 moles of Fe2S3, then there is .1 moles of Fe. Maximum mass of iron can be found by finding part b, and mulitplying that number by the molecular weight of iron

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