The balanced chemical equation for the complete combustion of c2h2 is: 2c2h2 + 5o2 → 4co2 + 2 h2o how many grams of o2 are required to react with exactly 0.500 mol of c2h2? 1.25 g 20.0 g 40.0 g 25.0 g

Option C

Explanation:

This is a problem of Stechiometry, so, to do this, let's write the equation again:

2C2H2 + 5O2 → 4CO2 + 2 H2O

According to the reaction, we can see that 2 moles of C2H" reacts with 5 moles of O2. So if we have 0.5 moles of C2H2, we only need to calculate the moles of O2 according to the above relation.

If:  moles C2H2/moles O2 = 2/5

Then: 0.5 / moles O2 = 2/5

Solving for moles O2:

2 moles O2 =  5 * 0.5

moles O2 = 5 * 0.5 / 2

moles O2 = 1.25 moles

Now that we have the moles, we can calculate the grams, using the molecular weight of O2, which is 32 g/mol, then the mass:

m = moles O2 * MM

Replacing we have:

m = 1.25 * 32

m = 40 g O2

And this is the mass required to react exactly with the 0.5 moles of C2H2.

im pretty sure its b