3. Use the mole ratio of CuO produced per mole of malachite to write a balanced equation for the malachite decomposition reaction. Assume that CO₂ is also a product of the decomposition.
CuCo3*Cu9OH)2 -----> 2Cuo+Co2+H2O
0.004522431 moles of malachite
0.01257071 moles of CuO
4. Predict the mass of CuO expected to result from the decomposition of the malachite, based on the balanced equation. 1g of Malachite was given. The mass of CuO produced (g): 0.72g
5. Compare the mass obtained from the mass predicted, and discuss reasons for any discrepancy.
It appears t me that 0.00452 moles malachite should have produced 2x that for CuO. Is that 0.0126 mols your experimental value? If so it is too high. I have no idea what may have gone wrong. You have provided no details for the experiment.
(a) Mass of an empty Erlenmeyer flask (g): 91.780g
(b) Mass of the Erlenmeyer flask with malachite(g): 92.780g
(c) Subtract (a) from (b) to obtain the mass of malachite (g): 1g
(c) Mass of Erlenmeyer flask with CuO(g): 92.500g
(d) Subtract (a) from (c) to obtain the mass of CuO produced (g): 0.72g
2. Calculate the following:
(a) moles of malachite in 1g: 222.1mw
0.004522431 moles of malachite
(b) moles of CuO produced: 79.55 mw
0.01257071 moles of CuO
If I read this right,
moles malachite in 1 g i 1/221.12 = 0.0452 (we have a slight difference in molar mass malachite--based on CuCO3.Cu(OH)2 I found 221.12) but that changes your value insignificantly.
Next. 0.72 looks ok BUT moles from that does not. If I divide 0.72/79.55 I get 0.00905 and not the 0.0126 you have.
Based on the 0.00452 moles of malachite you took you should have obtained 0.00452 x 2 = 0.00904 and that is just about as good as it gets in lab work.You don't have an error to explain. :-).
To predict the mass of CuO expected from the decomposition of malachite, we first need to calculate the molar mass of CuO.
The molar mass of CuO is calculated by finding the sum of the atomic masses of copper (Cu) and oxygen (O). The atomic mass of Cu is 63.55 g/mol, and the atomic mass of O is 16.00 g/mol.
So, the molar mass of CuO = (1 * atomic mass of Cu) + (1 * atomic mass of O) = 63.55 g/mol + 16.00 g/mol = 79.55 g/mol
Now, to calculate the mass of CuO produced, we can use the following steps:
1. Calculate the number of moles of CuO produced:
Given that the moles of CuO produced are 0.01257071 moles.
2. Use the molar mass of CuO to convert moles into grams:
Mass (g) = Moles * Molar mass
Mass (g) = 0.01257071 moles * 79.55 g/mol = 1.000 g
So, based on the balanced equation, the mass of CuO expected to result from the decomposition of 1 g of malachite is 1.000 g.
Now, let's compare the mass obtained from the mass predicted and discuss reasons for any discrepancy.
The mass obtained from the experiment is given as 0.72 g, while the predicted mass is 1.000 g. The reason for the discrepancy could be due to experimental errors, such as incomplete decomposition, loss of product during handling, or impurities in the malachite sample.
To minimize such discrepancies in future experiments, it is important to ensure complete and accurate decomposition of malachite, handle the products carefully to avoid any loss, and use pure malachite samples for accurate measurements. It is also advisable to repeat the experiment multiple times to obtain more reliable data and calculate averages for better accuracy.