SURVEY OF CHEMISTRY LABORATORY I

CHEM 1151L

REACTIONS OF COPPER

CAUTION!!!CAUTION!!!BE SURE TO WEAR SAFETY GLASSES AT

ALLTIMES IN THE LABORATORY

NO EXCEPTIONS TO THIS RULE!

- To demonstrate chemical changes

- To investigate the reactions of copper and its compounds

- Students will make a series of compounds with metallic copper and regenerate the elemental copper at the end

Cu → Cu(NO3)2 → Cu(OH)2 → CuO → CuSO4 → Cu

REACTIONS OF COPPER

Copper metal is used for- Water pipes

- Electrical wiring- Cookware

- Coins- Etc

There are extensive uses of the compounds of copper

- Widely used as pigments- Copper sulfate (CuSO4) is a fungicide

USES OF COPPER

SAMPLES OF COPPER AND ZINC

- Weigh about 1 gram of copper metal

- Cut with scissors

- Roll into a ball

- Record your observation of the copper metal

PREPARATION OF COPPER(II) NITRATE

- Work in the hood

- Add 10 mL of 16 M nitric acid (HNO3) into a clean 250mL

beaker

- Place the metal copper into the beaker of acid

PREPARATION OF COPPER(II) NITRATE3Cu + 8HNO3 → 3Cu(NO3)2 + 2NO + 4H2O

- Allow the copper to completely dissolve

PREPARATION OF COPPER(II) NITRATE

- Warm the solution gently to remove excess nitric acid

(brownish-red gas)

- Stop warming after all traces of brownish-red gas are gone

- Avoid excessive boiling

PREPARATION OF COPPER(II) NITRATE

- Observe and record the properties of copper(II)

nitrate

- Use litmus paper to test acidity of solution

- Blue litmus paper will turn red if solution is acidic

PREPARATION OF COPPER(II) NITRATE

- Allow the beaker to cool

- Place the beaker in an ice bath

- Add 15 mL of 6 M sodium hydroxide (NaOH) dropwise

with stirring

PREPARATION OF COPPER(II) HYDROXIDECu(NO3)2 + 2NaOH → Cu(OH)2 + 2NaNO3

- Use litmus paper to test if solution is basic

- Add a drop of the mixture to a strip of red litmus paper

- Blue color indicates the solution is basic

- The solution itself is blue so watch the “bleeding” portion

PREPARATION OF COPPER(II) HYDROXIDE

- Add more NaOH as necessary (drop by drop) until the solution is basic

- Rinse stirring rod into the solution when being removed from the solution

- Rinse the sides of the beaker into the solution

- Record all observations

PREPARATION OF COPPER(II) HYDROXIDE

- Add 50 mL of distilled water to the beaker containing Cu(OH)2

PREPARATION OF COPPER(II) OXIDECu(OH)2 + heat → CuO + H2O

- Gently boil the solution while stirring continuously

- Boil for an additional minute after a distinct color change

is observed

- Record all observations

PREPARATION OF COPPER(II) OXIDE

- Allow CuO to settle

- Pour off the clear liquid into another beaker

- Be careful not to lose any of the solid material (CuO)

- Add 50mL of distilled water and stir

- Pour off the water once settled

- Repeat the process twice

PREPARATION OF COPPER(II) SULFATECuO + H2SO4 → CuSO4 + H2O

- Stir the mixture

- Add concentrated sulfuric acid (H2SO4) dropwise until all of

the CuO dissolves

- A distinct color change will be observed

- Record all observations

PREPARATION OF COPPER(II) SULFATE

- Add about 3 grams of zinc to the CuSO4 solution

- Cover the solution with Parafilm

- Store it in a cabinet

PREPARATION OF COPPER(II) SULFATE

END OF FIRST LAB PERIOD

- Solution should turn from blue to colorless after all copper has

reacted

PREPARATION OF COPPERCuSO4 + Zn → Cu + ZnSO4

- Stir for solution to become colorless if the solution is still

blue

- Consult instructor before advancing to the next step

PREPARATION OF COPPERCuSO4 + Zn → Cu + ZnSO4

- Work in the hood

- Slowly add 5-10 mL of 12 M hydrochloric acid (HCl) to the

solution

Zn + 2HCl → H2 + ZnCl2

PREPARATION OF COPPER

- Remove excess pieces of zinc with forceps

- Use a wash bottle of distilled water to rinse the copper off the pieces of zinc as they are removed

- Mass and record a piece of filter paper and Petri dish together

PREPARATION OF COPPER

- Allow the copper to settle

- Place the filter paper in a Buchner funnel

PREPARATION OF COPPER

- Filter the solution through the Buchner funnel

PREPARATION OF COPPER

- Allow the funnel to drain completely

- Wash the copper with distilled water followed by acetone

- Use small amounts

PREPARATION OF COPPER

- Place the filter paper and copper on the massed Petri dish

- Dry it in the oven for a few minutes

- Make sure the filter paper does not burn

- Remove immediately when filter paper starts to turn brown

PREPARATION OF COPPER

- Remove sample from oven and allow to cool

- Mass copper together with filter paper and Petri dish

- Determine the mass of the copper recovered in your experiment

- Calculate percent recovery

PREPARATION OF COPPER

- Dispose of copper into the appropriate waste container

- Clean all glassware

- Return all equipment to their proper places

CLEAN UP