• Consider the reaction:

Fe₃O₄ + 4 C 3 Fe + 4 CO

What is the maximum mass of Fe which could be made from 115.0 g Fe₃O₄ of and 24.00 g C?

 

 

 

 

 

 

 

 

 

 

 

 

 

The trick here is to find the maximum amount of iron which could be made from each reactant. The lesser amount will then be the max possible:

C: (3 mol Fe/ 4 mol C)(24.00 g C/ 12.01 g C/mol C) = 1.499 mole

 

 

 

 

Fe₃O₄: (3 mol Fe/ mol Fe₃O₄)(115.0 gFe₃O₄/231.6 g Fe₃O₄/mol Fe₃O₄) = 1.490 mole

 

 

 

 

 

 

C: (3 mol Fe/ 4 mol C)(24.00 g C/ 12.01 g C/mol C) = 1.499 mole

Fe₃O₄: (3 mol Fe/ mol Fe₃O₄)(115.0 gFe₃O₄/231.6 g Fe₃O₄/mol Fe₃O₄) = 1.490 mole

\ Fe₃O₄ limits, can only make 1.490- moles.

 

 

 

 

 

 

 

So mass is then= (1.490 moles) (55.85 g/mole) = 83.22 g Fe

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Solubility Rules It is useful to remember some simple "rules" (really more like guidelines) to help in predicting reactions. For common compounds such as we see in general chemistry we can use the following rules: Nitrates (NO3-) are all soluble. Alkali metal (Li+, Na+, K+, Cs+, and Rb+) and ammonium (NH4+) salts are all soluble, with the exception of a few Lithium salts. Chloride, bromide, and iodide (Cl-, Br-, and I-) salts are generally soluble, except for the salts of silver, lead(II) and mercury(I) (Ag+, Pb2+ and Hg22+). Sulfates are soluble, except for the salts of barium {BaSO4}, lead(II) {PbSO4}, mercury(II) {HgSO4}, and calcium {CaSO4}. Most hydroxides are only slightly soluble (but see rule 2). Sulfides (S2-), carbonates (CO32-), phosphates (PO43-), and chromates (CrO42-) are only slightly soluble (but see rule 2). Examples using these rules may be found in the Module

© R A Paselk

Last modified 24 September 2009