Can anyone help me out here?

[palfreyman18]

I'm currently doing chemistry coursework and i need to know a few facts about the decomposition of Copper Carbonate. I need to collect a volume of gas, and, using mole calculations, find out which of 2 equations is correct. They are as follows:

2CuCO3 ----> Cu2O + CO2 + 1/2 O2

OR: CuCO3 -----> CuO + CO2

I think it's something to do with heating the CuCO3 in a crucible but as i need to measure a volume of gas i'm not sure. Can anyone help out here as this needs to be in by wednesday?

Thanks in advance

[jake-the-peg]

From what you are saying I imagine what they want you to do is to calculate the expected mass of residue based on the two equations.

[newtron]

http://www.chemistry-react.org/go/Tutorial/Tutorial_4642.html  This site shows what sounds like the exact problem that you are doing, and it asks some key questions.  I think the key is that the two different reactions form different amounts of gas.  For the first reaction, the decomposition 2 moles of CuCO3 forms a total 1.5 moles of gas (1 mole of CO2 and 1.2 mole of O2).  For the second reaction, the decomposition of 2 moles of CuCO3  forms 2 moles of gas (just CO2).  Based on the volume of gas that is formed, you can calculate how many moles of gas  you have using the ideal gas law (PV=nRt).  Solve for n.  I hope this helps.   

[newtron]

Sorry it was supposed to be 1/2 mole of O2.

[Gef]

The first equation is not balanced. However, in the first reaction took place the CuCO3 would lose about 42% of its mass and if the second took place (which is what actually happens) it would lose about 35% of its mass.

[palfreyman18]

Ah its ok now ive finished it now !! :D

thanks very much everyone for your help :)