Question

Question #34be2

Answer 1

Gravimetric stoichiometry is the branch of stoichiometry that deals with using the mass of one substance to calculate the mass of another substance in a chemical reaction.

Explanation:

For example, in the reaction

`"A → B"`

gravimetric stoichiometry asks the questions, "What mass of `"B"` can be formed from `x` g of `"A"`?" and "What mass of `"A"` is required to form `x` g of `"B"`?"

You always use the same type of steps.

• Write the balanced chemical equation.
• Convert `"mass of A" → "moles of A" → "moles of B" → "mass of B"`.

EXAMPLE

Calculate the mass of iron(III) oxide that can be produced by the reaction of 500 g of iron with excess oxygen.

Solution

Step 1. Write the balanced chemical equation.

`"4Fe" + "3O"_2 → "2Fe"_2"O"_3`

Step 2. Do the conversions.

`500 color(red)(cancel(color(black)("g Fe"))) × (1color(red)(cancel(color(black)("mol Fe"))))/(55.84 color(red)(cancel(color(black)("g Fe")))) × (2 color(red)(cancel(color(black)("mol Fe"_2"O"_3))))/(4 color(red)(cancel(color(black)("mol Fe")))) × ("159.7 g Fe"_2"O"_3)/(1 color(red)(cancel(color(black)("mol Fe"_2"O"_3)))) = "715 g Fe"_2"O"_3`