Question

How would your results for this experiment have been affected if you had removed the crucible from the Bunsen burner too soon?

PART 1: EXPERIMENTAL DATA
mass of empty crucible 88.000g
mass of crucible + Cu2CO3(OH)2 98.000g
mass of Cu2CO3(OH)2 added to crucible 10.000g
mass of crucible + CuO after heating 95.195g
mass of CuO remaining in crucible 7.195g

PART 2: CALCULATIONS
What is the balanced chemical equation for the reaction that takes place during this experiment? Hint: In addition to the CuO, both CO2 and H2O are produced.

Cu2CO3(OH)2=2CuO +H2O + CO2

Based on the amount of Cu2CO3(OH)2 you added to the crucible, what is the theoretical yield (in grams) of CuO for this experiment? Show your work.
10.00g Cu2CO3(OH)2 (1mole Cu2CO3(OH)2/221.1156g Cu2CO3(OH)2)
(2mol CuO/1 mol Cu2CO3(OH)2)
(79.546g CuO/1 mol CuO) = 7.195g CuO

What is the percent yield for this experiment? Show your work.

Percent Yield=(Actual Yield)/(Theoretical Yield)×100
2.805/7.195X100= 38.9%

Answer 1

Incorrect results from a lack of decomposition of the starting material and/or drying of the final product. The calculated product mass would be too large.

Explanation:

One of the slowest lessons in gravimetric analysis is the necessity of very thorough drying of samples. This is more important when the desired transformation is heat dependent, as this one is.