Chemistry 9701 · AS & A Level · An introduction to A Level organic chemistry
An introduction to A Level organic chemistry — practice question
Hydrogen is one possible energy source for future road vehicles. A difficulty that still needs solving is how to keep the hydrogen in the vehicle. A standard tank containing liquid hydrogen would need to be both pressurised and refrigerated. If such a tank were damaged in a collision, it could rupture, causing hydrogen to escape very quickly and explode.
Another option is a fuel tank filled with carbon nanotubes. Inside the tank, the hydrogen would be adsorbed onto the nanotube surface at a pressure of only a few atmospheres.
(a(i))
About how wide is a carbon nanotube?
(a(ii))
What structural arrangement does the carbon in a nanotube have?
(a(iii))[4]
Which forces might hold the hydrogen on the surface of the nanotubes? Explain your answer.
(b)[1]
The hydrogen atoms in a fuel tank packed with nanotubes are closer together than they are in liquid hydrogen. Suggest one benefit of this.
(c)[4]
When a nanotube-packed fuel tank contains hydrogen, the hydrogen pressure in the tank is steady. As hydrogen gas is taken out of the tank to power the car, the pressure falls only slightly for a period of time. State Le Chatelier’s principle, and suggest how it explains this observation.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “It is a few nanometres wide (accept $0.5$-$10\,\mathrm{nm}$)” …