Answer:
15.362g of O2
Explanation:
2C2H2 + 5O2 -> 4CO2 + 2H2O
(when you have a hydrocarbon mixing with oxygen, just think that it always makes co2 and H2o, the rest you balance)
so basic stochiometry rule, start with given, end with finding
given: 5g C2H2
finding: x g of O2
when doing dimensional analysis and multiplying fractions, its all in a specific order, what is in the denominator of the next fraction has to have the same unit of the previous numerator, such as 1g/1mol x 2mol/1g, fraction 1 has g on top where as fraction 2 has g on bottom, to cancel out. The last fraction with the unit on the numerator is the only unit that has to remain. So lets start
5g C2H2 x (1mol C2H2 / 26.038g C2H2) x (5mol O2 / 2 mol C2H2) x (32.0g O2 / 1mol O2)
You see how if you cancel out the units correctly, all you have left is g O2, which means you did it right.
Now simplifying it should give you 15.362g of O2
Hope that answers your question
