Experimenting with copper

Date: 07/08/13
Aim: To observe and measure the percentage recovery of copper and recognise the chemical changes
Hypothesis: It is expected that 25-30% of the copper will recover after the series of experiments.
Material:
Beaker
Copper
Watch Glass
Vial
Weighing scale
Measuring cylinder
Nitric acid solution
Fume hood
Sodium hydroxide solution
Glass stirring rod
Distilled water
Bunsen Burner
Wash bottle
Sulphuric acid
Zinc metal
Evaporating Dish
Stage 1
Method:
1. A vial was given containing approximately 1.5g of copper. The vial containing the copper was weighed and the mass was recorded
2. The copper was tipped into a 250ml beaker. The empty vial was weighed and the mass was recorded
3. 15ml of nitric acid solution was measured out in a measuring cylinder. In the fume hood, the acid solution was poured into the beaker containing copper
4. A watch glass was put on top of the beaker
5. The reaction continued until all the copper metal was disappeared. The product was kept in the beaker for stage 2 of the experiment.

Stage 2
Method:
1. 40 ml of sodium hydroxide was slowly added to the solution in the beaker, while stirring with the glass rod
2. The product was kept in the beaker for stage 3 of the experiment
Stage 3
Method:
1. 100ml of distilled water was added to the beaker
2. The beaker was heated and its contents, while stirring constantly
3. The solution was stirred until it boils and no changes can be seen
4. The stirring rod was lifted out of the solution. A wash bottle was used to wash any particles on the stirring rod into the beaker, then the stirring rod was removed
5. The beaker and its contents were allowed to cool down for 5 minutes
6. Without losing any solid, the clear liquid solution was poured into another beaker
7. The solid in the beaker was washed by adding 100ml of distilled water while stirring. Leftover particles from the stirring rod were washed away into the beaker. The solid was left to settle and decant the clear liquid
8. The washing procedure was repeated using a further 100ml of distilled water. The solid was left to settle and decant the clear liquid.
9. The product was kept in the beaker for stage 4 of the experiment
Stage 4
Method:
1. 50ml of the sulphuric acid solution was added to the beaker and stirred until no further changes took place.
2. The product was kept in the beaker for stage 5 of the experiment
Stage 5
Method:
1. 5g of zinc metal was added to the product in the beaker. A watch glass was put on top of the beaker
2. The beaker was swirled occasionally. Observations was recorded.
3. The reaction continued until all the zinc had disappeared and any other forms of reaction (bubbling) were complete
4. The product was kept in the beaker for stage 6 of the experiment

Stage 6
Method:
1. The clear liquid was decanted from the solid in the beaker. The product was washed with 50ml of distilled water. It was stirred and settled, then decanted again. This procedure of washing and decanting was repeated two more times.
2. A clean, dry evaporating dish was weighed
3. Most the solid was poured into the evaporating dish from the beaker
4. A wash bottle was used to transfer the remaining solids in the beaker
5. The product was dried by heating the evaporating dish over a Bunsen burner/steam bath
6. The dish was left to cool and dry
7. The evaporating dish containing the dry product was weighed
Results
The starting mass of copper was 3.11g
Stage one

Observations:
Steam/gassy substance
Nitric acid, mixed with copper turns green
Gassy substance coming out of the beaker is orange/brown
Green substance starts bubbling at the bottom of the beaker
Turns into a darker colour (black)
After the beaker is kept to rest, the substance inside turns a turquoise colour
Stage two
Double Displacement reaction
Observations:
Formed blue cloudy mixture
Sticky blue residue
Change of temperature – warm