Question

1. Name three observations/signs that might indicate that a chemical reaction has occurred.

2. Write a balanced chemical equation for the reaction of iron with oxygen to form iron oxide (Fe₂O₃). Then write a description of what you would observe as a piece of iron rusts. What was the sign of the chemical reaction in which iron rusts into iron(III) oxide?

3. Define the following terms:

     oxidation-

    reduction-

4. For the reaction in question 2, which reactant is oxidized and which is reduced?

5. In the first reaction in this lab you dissolve the copper metal in nitric acid. Why must this reaction be performed in the hood until the reaction is complete?

Answer 1

Q1.

color change, solid formation, bubble/gas formation

Q2

equation for:

Fe(s) + O2(g) = Fe2O3(s)

balance

2Fe(s) + 3/2O2(g) = Fe2O3(s)

sign of iron to rust will be appearance of "rusty" color or "redish" colored material, which is Fe2O3, Fe(s) is greayblack

Q3

in REDOX equations:

Reduction = species that GAINS electrons

Oxidation = process in which a specie will LOSS electrons

Reducing agent = The species that favors reduction, i.e. it will oxidize in order to reduce another species

Oxidizing agent = The species that favors oxidation, i.e. it will reduce in order to oxidise another species

Q4

Fe goes from 0 in Fe(s) to Fe+3 in Fe2O3, it loses 3 electrons, so it is oxidized

O goes from 0 in O2(g) to O-2 in Fe2O3, it loses 2 electrons, so it is reduced

Q5

Cu(s) + 2HNO3(aq) --> H2(g) ´+ Cu+2 + 2NO3-

H2(g) is produced, we need the fume hood for this

Also note that HNO3 may cause fumes which are very irritating