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

in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.