SURVEY OF CHEMISTRY LABORATORY I CHEM 1151L REACTIONS OF COPPER

CAUTION!!! BE SURE TO WEAR SAFETY GLASSES AT ALL TIMES IN THE LABORATORY NO EXCEPTIONS TO THIS RULE!

REACTIONS OF COPPER - 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

USES 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

SAMPLES OF COPPER AND ZINC

PREPARATION OF COPPER(II) NITRATE - 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 3Cu + 8HNO3 → 3Cu(NO3)2 + 2NO + 4H2O - 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) NITRATE - 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) HYDROXIDE Cu(NO3)2 + 2NaOH → Cu(OH)2 + 2NaNO3 - 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) HYDROXIDE - 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) OXIDE Cu(OH)2 + heat → CuO + H2O - Add 50 mL of distilled water to the beaker containing Cu(OH)2

PREPARATION OF COPPER(II) OXIDE - 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) SULFATE CuO + H2SO4 → CuSO4 + H2O - 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) SULFATE - 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

END OF FIRST LAB PERIOD

PREPARATION OF COPPER CuSO4 + Zn → Cu + ZnSO4 - Solution should turn from blue to colorless after all copper has reacted

PREPARATION OF COPPER CuSO4 + 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 COPPER Zn + 2HCl → H2 + ZnCl2 - Work in the hood - Slowly add 5-10 mL of 12 M hydrochloric acid (HCl) to the solution

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

- Filter the solution through the 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

CLEAN UP - Dispose of copper into the appropriate waste container - Clean all glassware - Return all equipment to their proper places