Malachite Data and Results PDF

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Malachite...

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DATA AND RESULTS Duy Vu 073 06/06/2020 Record the following masses:

1 2 3

4 5

Empty Crucible Crucible plus malachite Malachite (Entry 2 – Entry 1) Crucible plus CuO (trial 1) Crucible plus CuO (trial 2) Crucible plus CuO (trial 3 if necessary) Crucible plus CuO at constant weight Copper oxide (Entry 4 – Entry 1)

Mass (g) 10.68 13.77 3.09 12.86 12.83 12.82 12.84 2.16

DATA AND RESULTS Calculation of Reaction Stoichiometry First calculate the molar masses of malachite and copper oxide from their molecular formulas. The moles of malachite reactant and CuO product can the be calculated by dividing their respective masses by the corresponding molar masses. Based upon these calculations, determine the number of moles of CuO produced per mole of malachite decomposed.

Molar mass of malachite, CuCO3Cu(OH)2 (g/mol) Mass of malachite (g) (See entry 3 in data table) Moles of malachite reactant Molar mass of CuO (g/mol) Mass of CuO (g) (See Entry 5 in data table) Moles of CuO produced Moles of CuO product/Moles of malachite reactant

Amoun t 222 3.09 0.0139 80 2.16 0.027 1.942

Questions: 1. If the mass of copper oxide product that remained in the crucible after heating is less than that of malachite which was originally added to the crucible, where did the missing mass go? (Hint: The molecular formula for malachite could also be written as (CuO)2(CO2)(H2O)). The missing mass in the reaction transfers to carbon dioxide in gases and water in liquid, since mass reactants = mass products (mmalachite – mCuO = mCO2 + mH2O)

2. Write a balanced chemical equation for the decomposition of malachite including the physical states of the reactant and products. CuCO3Cu(OH)2 (s) -> 2CuO (s) + CO2 (g) + H2O (l) That’s why the ratio of moles of CuO product/Moles of malachite reactant is almost two in reality, the loss in decomposition process....