Iron oxide and hydrogen react to form iron and water in the following chemical equation:
Fe2O3 + 3H2 2Fe + 3H20
How many grams of iron oxide ( Fe2O3) are needed to create 172 grams of iron (Fe)?
245.9 g Fe2O3
86g Fe2O3
30.07g Fe203
55.85g Fe2O3

The answer to your question is 245.9 g of Fe₂O₃

Explanation:

Data

grams of Fe₂O₃ = ?

grams of Fe = 172 g

Balanced chemical reaction

                Fe₂O₃  +  3H₂   ⇒   2Fe  +  3H₂O

Process

1.- Calculate the molar mass of of Iron Oxide and Iron

Fe₂O₃ = (2 x 56) + (3 x 16) = 112 + 48 = 160 g

2Fe = 2 x 56 = 112 g

2.- Use proportions and cross multiplication to solve this problem

                  160 g of Fe₂O₃ 112 g of Fe

                      x                   172 g of Fe

                      x = (172 x 160)/112

                      x = 27520/112

                     x = 245.9 g of Fe₂O₃

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.