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# Thermal Decomposition

Calculate the following:
(a) Moles of malachite in 1g: Cu2CO3(OH)2
Cu= 63.55 x 2=127.1 C= 12.01 O= 16 x 5= 80 H=1.008 x 2= 2.016

(b) Moles of CuO produced:
.72 g CuO produced

(c) Ratio of moles of CuO produced per moles of malachite decomposed

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.

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.

6. Suggest a way to demonstrate that CO2 is a product of the reaction.

#### Solution Preview

(a) moles of malachite in 1g: Cu2CO3(OH)2
First we calculate the molar mass of Cu2CO3(OH)2. You started out okay by finding the masses of all the atoms. Now, just add them together. It is 221.13 g. This is the mass of one mol.
Therefore, all we do now is:
(1 mol/221.13 g)(1 g) = 0.00452 mol

b) moles of CuO produced:
We determine the molar mass of CuO and then do the same thing we did above: Molar mass of CuO is 79.55 g. This is the mass of one mol.
Therefore,
(1 mol/79.55 g)(0.72 g) = 0.00905 mol

(c) ratio of moles of CuO produced per moles of malachite ...

#### Solution Summary

This solution provides calculations for finding moles and mole ratios of products.

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