This leads on directly from the previous position molar volume .
The video works through a problem to find the formula of a hydrocarbon if we know the volume of oxygen used and the volume of carbon dioxide produced in combustion of the hydrocarbon.
Watch out for the last practice question, it’s a horror 😱!
Practice questions
4. 10 cm3 of a hydrocarbon reacts completely with 40 cm3 of oxygen to produce 30 cm3 of carbon dioxide at room temperature and pressure. What is the formula of the hydrocarbon?
5. When 15 cm3 of a hydrocarbon was reacted with 60 cm3 of oxygen (an excess), the final volume was found to be 45 cm3 at room temperature and pressure. The resulting mixture was then bubbled through sodium hydroxide solution to remove the carbon dioxide and the volume decreased to 15 cm3. Find the formula of the hydrocarbon.
6. 10 cm3 of a hydrocarbon, C3Hx, was exploded in excess oxygen at 105°C. The volume expanded by 5 cm3. Find the formula of the hydrocarbon and the volume of oxygen used in this reaction.
