CHEM_120L_Notes - Experiment1 Sunday,November27,2005 3:59PM...

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Experiment 1 Sunday, November 27, 2005 3:59 PM Need to Know Know the reaction equations, how the reactions occur (ex. spontaneously, by heating, etc.) and the physical  descriptions and color of both the reactants and products o Ex. CuO (s) (black solid) + H2SO4 (aq) + H2O --> Cu(SO)4 (aq) (blue solution) + H2O Know how to calculate percent yield (i.e. CuSO4 was obtained from the reaction of CuO with sulfuric acid.  If 2.5  g of CuSO4 was obtained from 5.0 g of CuO, what is the percent yield?)   Purpose To synthesize different copper compounds   Theory  Many organic and inorganic compounds are synthesized by the chemical industry even though they can be  found in nature, because a limited natural supply or expensive extraction process may make synthesis more  economical Things we have to take into consideration when synthesizing: o Availability of equipment o Percentage yield o Value of by-products   This experiment illustrates the synthesis of several copper compounds from metallic copper: o Cu -> Cu(NO3)2 -> Cu(OH)2 -> CuO -> CuSO4--5H2O -> Cu We expect to get the same mass of copper at the end than what we started with…in order to do so, we must  prevent loss by: o Avoiding spattering while boiling o Not leaving product on the sides of beakers o Not spilling the product o Purifying precipitates by washing efficiently then drying completely before weighing   Procedure Part 1: Synthesis of Copper(II) Nitrate and Copper(II) Hydroxide o Cu + 4HNO3 -> Cu(NO3)2 + 2NO2 + 2H2O Reaction notes: It is SPONTANEOUS We carry this out in the fume hood and swirl the reaction mixture to remove any  gases trapped in the solution o Cu(NO3)2 + 2NaOH -> Cu(OH)2 + 2NaNO3  Reaction notes: It is SPONTANEOUS The solution should be basic (alkaline) after the addition Cu(OH)2, the product, is a gelatinous precipitate Cu(OH)2, the product, is  BLUE Part 2: Synthesis of Copper(II) Oxide o Cu(OH)2 –Δ-> CuO + H2O  Reaction notes: It is BY HEATING We want to convert Cu(OH)2 to CuO because it is a LESS GELATINOUS  precipitate than Cu(OH)2 is, and thus easier to isolate
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The  BLUE  Cu(OH)2 becomes  BLACK  CuO If heating doesn't do the trick we add MORE NaOH o Filtration Filter with a suction filter flask and a Buchner funnel Wash the CuO with water both to get it out of the beaker and because it is wet with a  solution which contains NaNO3 and NaOH, and we want to get rid of it Part 3: Synthesis of Copper(II) Sulfate o CuO + H2SO4 –Δ-> CuSO4 + H2O Reaction notes: It is BY HEATING As the CuSO
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This note was uploaded on 04/18/2011 for the course SCIENCE 120L taught by Professor D during the Spring '10 term at Waterloo.

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CHEM_120L_Notes - Experiment1 Sunday,November27,2005 3:59PM...

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