The Fe 2 + ( 55.845 g/mol) content of a 2.349 g steel sample dissolved in 50.00 mL of an acidic solution was determined by tiration with a standardized 0.100 M potassium permanganate ( KMnO 4 , 158.034 g/mol) solution. The titration required 43.16 mL to reach the end point. What is the concentration of iron in the steel sample? Express your answer as grams of Fe per gram of steel. MnO − 4 + 8 H + + 5 Fe 2 + − ⇀ ↽ − Mn 2 + + 5 Fe 3 + + 4 H 2 O

0.513 iron per gram of steel is the concentration of iron in the steel sample.

Explanation:

Molarity of solution = 0.100 M

Volume of solution = 43.16 mL = 0.04316 L( 1mL=0.001 L)

Moles of = n

1 mole of gives 1 mole of potassium ion and manganate ions.

Moles of

According to reaction, 1 mole of manganate ion reacts with 5 moles of ferrous ions.Then 0.004316 mole of manganate ion will react with L:

of ferrous ions

Mass of 0.02158 moles of ferrous ion:

0.02158 mol × 55.845 g/mol = 1.2051 g

Mass of steel sample = 2.349 g

Concentration on iron in sample :

iron per gram of steel

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-