Hi all,
The last question of a worksheet on the ideal gas equation is confusing me a bit. The question reads:
"20cm3 of a gaseous alkene is exploded with 150cm3 of oxygen. The gases produced in this reaction occupied 110cm3. When these gases were shaken with aqueous sodium hydroxide to remove any excess carbon dioxide remaining after the reaction, the final volume was 30cm3. (All volumes were measured at the same temperature and pressure, and all water produced in the reaction is assumed to be in the liquid phase)."
The first part of the question was to write an equation for the reaction of carbon dioxide with sodium hydroxide, which I believe is CO2 (g) + 2NaOH (aq) -> Na2CO3 (aq) + H2O (l).
However, the second part is where I have run into problems - it asks for the formula of the alkene. Since I know that an alkene burned in oxygen produces carbon dioxide and water, I worked out that the volume of water produced is 60cm3 (as 20+150 is 170, but only 110cm3 of gas was produced, and any water produced was liquid). I have also worked out that, since 110cm3 of gas was produced, and the final volume was 30cm3, 80cm3 CO2 was removed by the sodium hydroxide. Since the only gases (apart from the alkene) involved in the equation are carbon dioxide and oxygen, the 30cm3 remaining must be excess oxygen.
I'm not sure where to go from this information though? Any advice greatfully received!