Acetylene c2h2 burns according to the following reaction: c2h2+5o2+2h2o.?

Question

Suppose 1.20g of c2h2 is mixed with 3.50g of o2 in a closed, steel container, and the mixture is ignited. What substances will be foundd in the mixture left when the burning is complete? I have no clue how to approach this...

Answer 1

First, your reaction is all screwed up. It should be
2C2H2 + 5 O2 -> 4CO2 + 2 H2O.
So after you ignite the acetylene/oxygen mix, you will have water and CO2 left, plus any of the reagents if their initial concentrations were not in accord with the reaction.

Here, the mole weight of C2H2 is 26 and of O2 is 32. So you can divide each gas by its mol-weight to see what the moles of each are. Here you have about 0.04 moles of acetylne and about 0.12 moles of oxygen. To burn all the acetylene, we would need about 0.10 moles of oxygen (two moles acetylene to 5 moles oxygen). So we should also see some oxygen in the product mix.

Answer 2

First of all, write out the rest out the reaction, and balance it.

Then calculate for the L.R. (Limiting reagent). This is the agent that will get used up, and you will be left with the other. You use the L.R. to calculate the yields of the products, which should be CO2 and H2O (I believe). You also add into the mix the left over of the XS Reagent, and booyah - and explanation without the answers!