Within marine continental slopes and permafrost regions, immense quantities of methane are trapped within water-ice cages as 'methane hydrate', CH4⋅xH2O\text{CH}_4 \cdot x\text{H}_2\text{O}CH4⋅xH2O. Methane makes up about 13.4%13.4\%13.4% of the mass of 'methane hydrate'.
Scientists and climatologists are concerned that rising ocean temperatures or tectonic shifts will destabilise these hydrate deposits, releasing massive volumes of gas into the oceans and atmosphere.
The H-O-H\text{H-O-H}H-O-H bond angle in the ice lattice of the clathrate cage is approximately 109∘109^\circ109∘, whereas in free gaseous H2O\text{H}_2\text{O}H2O molecules it is about 104.5∘104.5^\circ104.5∘. Explain why there is this difference.
Why are scientists and climatologists highly concerned about the release of methane gas into the atmosphere?
Determine the formula of 'methane hydrate', CH4⋅xH2O\text{CH}_4 \cdot x\text{H}_2\text{O}CH4⋅xH2O. In the formula, show the value of xxx to two decimal places.
Calculate the volume of methane gas, in dm3\text{dm}^3dm3, that would be released from the melting of each 2.20 kg2.20\text{ kg}2.20 kg of 'methane hydrate' at a temperature of 15∘C15^\circ\text{C}15∘C and a pressure of 101 kPa101\text{ kPa}101 kPa. Give your answer to three significant figures.
Suggest why some energy and environmental engineering companies are highly interested in these deep-ocean methane hydrate deposits.
199 exam-style questions on OCR A A Level Chemistry Atoms and reactions, covering Atomic structure and isotopes, Compounds, formulae and equations, Amount of substance, Acids, and Redox. Each one has a worked solution and a mark scheme showing where the marks go.