10cm3 of a gaseous hydrocarbon, C2HX required 30cm3 of oxygen for complete

Question

combustion. If steam and 20cm3 of carbon (IV) oxide were produced, what is the value of
X?

Answer 1

First, we need to write the balanced chemical equation for the combustion of hydrocarbon C2HX:

C2HX + O2 -> CO2 + H2O

From the information provided, we can set up a mole ratio between the hydrocarbon and oxygen:

1 mole of C2HX requires 1 mole of O2

Next, we need to calculate the number of moles of oxygen required for complete combustion of 10cm3 of C2HX. To do this, we will use the ideal gas law:

PV = nRT

n = PV/RT

n(Oxygen) = (30/1000)L x 1 atm / (0.0821 L.atm/mol.K x 293 K) = 0.00127 moles

Since the mole ratio between C2HX and O2 is 1:1, 0.00127 moles of oxygen will react with 0.00127 moles of C2HX.

Now, let's calculate the number of moles of carbon (IV) oxide produced. We know that 20cm3 of CO2 are produced, so:

n(CO2) = 20/1000 L x 1 atm / (0.0821 L.atm/mol.K x 293 K) = 0.0008 moles

Since 2 moles of CO2 are produced from 1 mole of C2HX, the number of moles of C2HX is:

n(C2HX) = 0.0008/2 = 0.0004 moles

Now we can calculate the value of X by looking at the molecular formula of C2HX. Since we have found that 0.0004 moles of C2HX were reacted, we can conclude that X = 3.

Therefore, the value of X in the hydrocarbon C2HX is 3.