You have 72 g of the compound C2Hx, where x is the maximum number of hydrogens that can fit around two carbon atoms and still create a stable lewis dot structure.

Question

If you allow all of this sample to react with excess oxygen, and then allow the products to cool to room temperature, how many moles of liquid product will you have?

Answer 1

The maximum number of hydrogens in a 2 carbon molecule is 6 (2n + 2). Thus, the compound would be C₂H₆.

Combustion of C₂H₆:

2C₂H₆(g) + 7O₂(g) ===> 4CO₂(g) + 6H₂O(l)

moles of C₂H₆ = 72 g x 1 mol/30 g = 2.4 moles

moles of liquid water produced = 2.4 moles C₂H₆ x 6 moles H₂O/2 moles C₂H₆ = 7.2 moles H₂O(l)