Use Quantitative Analysis and Chemical Function to Calculate the Mass Percentage of Cuco3 in the Mixture of Cuo and Cuco3

Chemistry 1A                                                                                                                

Experiment 2

Tittle: quantitative analysis of a mixture (%CuCO3)

Propose: Use quantitative analysis and chemical function to calculate the mass percentage of CuCO3 in the mixture of CuO and CuCO3.

Introduction:

 Quantitative analysis is concerned with the determination of the amounts of one particular substance in a mixture. Quantitative analysis is to produce results that are as precise and accurate as possible. The analysis is performed more than once, usually a minimum of three times. The results of all the experimental trials are combined to give one single answer, usually the average value of all the trials.

 In this experiment, we will identify the percentage of CuCO3 in the mixture of CuO and CuCO3.  Heat the sample to decompose the CuCO3. The loss of mass upon heating will allow you to calculate the amount of CO2 produce, which will allow you to use stoichiometry and calculate the original mass of CuCO3 present.

Equipment: Crucible, Bunsen burner, analytical balance, ring stand, clay triangle, wire gauze, clamp, crucible tongs.

Procedure:

1. Get the unknown example from teacher, and divide the mixture in three separate samples.
2. Weigh three clean and dry crucibles separately on the analytical balance, and record mass of empty crucible
3. Put 3 mixture samples to three crucibles, and weigh the mass of crucibles and mixture, and record data
4. Mound clay triangle on a ring stand to hold crucibles and heat each of crucibles with a Bunsen burner (top of outer flame) for 5 minutes
5. After heating, put the crucible on the wire gauze to cool down the crucible to room temperature and weigh the crucible, and record data
6. Repeat heating and weighing crucible 3 times, and record weight of crucible after each weigh
7. Calculate the percentage mass of CuCO3 of each sample, and get the average value

Data & calculation:

 Unknown number: 572

  Chemical equation: copper(II) carbonate + heat → copper(II) oxide + carbon dioxide

  Molar mass of CO2: 44.01g/mol

  Molar mass of CuCO3: 123.56g/mol