a) moles of malachite in 1g:
1g / (221.12g/mol) = .004522 mol
(b) moles of CuO produced:
.72g / (79.55g/mol) = .009051 mol
(c) ratio of moles of CuO produced per moles of malachite decomposed:
2CuO/CuCO3(OH)2 2*79.5/221.1 = 0.719
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
4. Predict the mass of CuO expected to result from the decomposition of the malachite, based on the balanced equation.
5. Compare the mass obtained from the mass predicted, and discuss reasons for any discrepancy.
I THINK I've taken care of this at the original post.
To predict the mass of CuO expected to result from the decomposition of malachite, we need to use stoichiometry. From the balanced equation:
CuCO3*Cu9OH)2 -----> 2CuO + CO2 + H2O
we can see that the mole ratio between CuO and malachite is 2:1.
Given that we have already calculated the moles of malachite in part (a) as 0.004522 mol, we can use this value to calculate the moles of CuO produced:
Moles of CuO = (0.004522 mol malachite) * (2 mol CuO / 1 mol malachite) = 0.009044 mol CuO
Now, we can calculate the mass of CuO using the molar mass of CuO:
Mass of CuO = (0.009044 mol CuO) * (79.55 g/mol CuO) = 0.719 g CuO
Therefore, the mass of CuO expected to result from the decomposition of malachite is 0.719 grams.
To compare the mass obtained from the mass predicted, we need the actual measured mass of CuO obtained from the experiment. If the actual mass obtained is different from the predicted mass, there could be several reasons for the discrepancy:
1. Incomplete reaction: The reaction may not have gone to completion, resulting in a lower mass of CuO obtained.
2. Side reactions: Other reactions may have occurred during the decomposition process, leading to the formation of different products and influencing the mass obtained.
3. Impurities: The starting material, malachite, could have contained impurities that affected the reaction and the resulting mass of CuO.
4. Experimental errors: Errors in measurements, calculations, or procedural steps could also contribute to the discrepancy between the predicted and obtained mass.
It is important to compare the experimental and predicted results to identify any discrepancies and analyze the possible causes to improve future experiments and obtain more accurate results.
To predict the mass of CuO expected to result from the decomposition of malachite, you can use stoichiometry.
First, calculate the moles of malachite decomposed, which you've already calculated in part (a) as 0.004522 mol.
Since the balanced equation you wrote in part (c) shows that 2 moles of CuO are produced per mole of malachite decomposed, you can now use this mole ratio to convert moles of malachite to moles of CuO.
Moles of CuO produced = moles of malachite decomposed * (2 moles of CuO / 1 mole of malachite)
= 0.004522 mol * 2
= 0.009044 mol
Next, to calculate the mass of CuO, you need to multiply the number of moles of CuO by its molar mass, which is 79.55 g/mol.
Mass of CuO = moles of CuO produced * molar mass of CuO
= 0.009044 mol * 79.55 g/mol
= 0.7191 g
So, based on the balanced equation, you would expect to obtain approximately 0.7191 grams of CuO from the decomposition of the malachite.
Finally, you can compare the mass obtained from the predicted mass and discuss reasons for any discrepancy. If the mass obtained experimentally differs from the predicted mass, it could be due to factors like incomplete reaction, presence of impurities, measurement errors, or other experimental limitations. It's important to consider the experimental conditions and any possible sources of error that could affect the accuracy of the result.