The reaction, 4fe (s) + 3o2 (g) à 2 fe2o3 (s), is the rusting of iron. what occurs as the reaction proceeds? a precipitate is formed the color of the solid will change a new odor is given off the solution bubbles

the color of the solid will change

Explanation:

A chemical reaction is defined as the reaction in which a change in chemical composition takes place. A new substance is formed in these reactions.

Example: Oxidation of iron to ferric oxide is a chemical change.

Here iron which is grey in color changes first to green and then turns brownish red.

Characteristics of a chemical reaction:

1. change in color

2. heat is gained or lost

3. evolution of gas

4. formation of precipitate

first, consult an activity series chart to determine if al is more reactive than fe. it is, so it will replace the fe. now, one can continue with the problem.

next, make sure you have a correctly balanced equation.

3feo + 2al ==> 3fe + al2o3

now, determine which reactant (feo or al) is in limiting supply.

moles feo present = 125 g x 1 mole/71.8 g = 1.74 moles

moles al present = 25.0 g x 1 mole/26.98 g = 0.927 moles

since from the balanced equation, it take 3 mol feo for every 2 mol al, al will be limiting.

you can determine this simply by dividing moles of each by their coefficient in the balanced equation. for example: 1.74/3 = 0.58 and 0.927/2 = 0.464. al is less, so it is limiting.

finally, using the stoichiometry in the balanced eq. determine mass of fe that can be produced from 0.927 moles of al.

0.927 moles al x 3 moles fe/2 moles al x 55.8 g/mole = 77.6 g