I need to write a balanced equation for this problem and am having difficulty doing so.
The question is this: 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.
Here are my numbers
moles of CuO produced 141.57
moles of malachite in 1g 221.12
Predict the mass of CuO expected to result from the decomposition of the malachite, based on the balanced equation.
Compare the mass obtained from the mass predicted, and give reasons for discrepancy.
Suggest a way to demonstrate that CO2 is a product of the reaction.
responded below but not answered.
900
To write a balanced equation for the malachite decomposition reaction, you first need to understand the mole ratio between CuO and malachite. The mole ratio is the ratio of the number of moles of each substance involved in the reaction.
In this case, the problem provides the number of moles of CuO produced (141.57 moles) and the number of moles of malachite (221.12 moles).
To find the mole ratio between CuO and malachite, divide the number of moles of CuO by the number of moles of malachite:
Mole ratio = Moles of CuO / Moles of malachite
Mole ratio = 141.57 / 221.12
This gives you the mole ratio, which can be represented as a whole number ratio in the balanced equation.
Next, you need to write the balanced equation using this mole ratio. Assuming CO2 is also a product of the reaction, the balanced equation can be written as follows:
2CuCO3(s) -> 2CuO(s) + CO2(g)
In this equation, malachite (CuCO3) decomposes to form CuO and CO2. The coefficients indicate the mole ratio: for every 2 moles of malachite, 2 moles of CuO and 1 mole of CO2 are produced.
Now, to predict the mass of CuO expected from the decomposition of the malachite, you need to use stoichiometry. Stoichiometry allows you to calculate the mass of one substance based on the mass of another substance and the mole ratio from the balanced equation.
The given number of moles of malachite (221.12 moles) can be converted to grams using its molar mass. Given that the molar mass of malachite (CuCO3) is 221.12 g/mol, this means that 1 mole of malachite weighs 221.12 grams.
To calculate the mass of CuO produced, multiply the moles of malachite by the mole ratio of CuO to malachite:
Mass of CuO produced = Moles of malachite x Molar mass of CuO
Mass of CuO produced = 221.12 x (Molar mass of CuO)
For the discrepancy between the predicted and obtained masses of CuO, several factors could contribute. These include experimental errors, the purity of the malachite sample, incomplete reactions, or losses during handling or filtration.
To demonstrate that CO2 is a product of the reaction, several methods can be used. Here are a couple of suggestions:
1. Gas collection: Collect the gas generated during the reaction in a gas collection apparatus, such as a gas syringe or a gas measuring tube. The volume of gas collected can be measured, and it can be identified as CO2 by performing a test with lime water. CO2 gas reacts with lime water and forms a white precipitate of calcium carbonate.
2. pH change: Since CO2 is acidic, you can observe the pH change in a solution as CO2 is produced. Collect the gas in a container filled with a solution sensitive to pH, such as a universal indicator solution. CO2 dissolves in water and forms carbonic acid, which would cause a decrease in pH, resulting in a color change in the indicator solution.
Remember, when performing experiments, always prioritize safety precautions and follow appropriate guidelines and protocols.