[aaronmar]

In lab I am given a series of 5 chemical reactions.  I am having trouble answering some of the questions involving results based on laboratory error.  Here are the reactions sequentially..

1.  8 mol Nitric Acid (aq) + 3 mol elemental copper (s) + 1 mol oxygen gas --> 3 mol Copper (II) Nitrate (aq) + 4 mol water + 2 mol nitrogen dioxide (g)

2. 1 mol Copper (II) Nitrate (aq) + 2 mol Sodium Hydroxide (aq) --> 1 mol Copper (II) Hydroxide (s) + 2 mol Sodium Nitrate (aq)

3. 1 mol Copper (II) Hydroxide (s) --> 1 mol Copper (II) Oxide (s) + 1 mol water

4. 1 mol Copper Oxide (s) + 1 mol sulfuric acid (aq) --> 1 mol Copper (II) Sulfate (aq) + 1 mol water

5. 1 mol Copper (II) Sulfate (aq) + 1 mol Elemental Zinc (s) --> 1 mol zinc (II) sulfate (aq) + 1 mol elemental copper (s)

The questions I have not answered are as follows:

Describe whether the error introduced would result in a high or low value for the Cu recovery, or would not affect the results.

1.  Insufficient NaOH added in step 2.

2. The washings in Step 5 are insufficient to remove all of the solution residues from the copper.

3. The copper is not completely dry in step 1

[Borek]

Please read forum rules. You must have some thoughts?

[aaronmar]

My mistake.. well I think that the copper recovery cannot become high, I'm just having problems determining whether it has no effect or reduces copper recovery.  Does it have to do with limiting reactants or is there some logic I'm missing?

[Borek]

Limiting reactant is a key word for step 2. Otherwise you must just think about what happens. For example, which precipitate - wet or dry - is heavier?