Because nuclear energy (stored among particles inside atoms) is millions of times more dense than chemical energy (stored among atoms in molecules), nuclear reactors belong high on our long list of energy alternatives.
Butanol, however, has four carbon atoms in its molecules, whereas ethanol has two.
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It has more carbon atoms in its molecules (four, instead of two), which means more energy per litre though it is still only 85% as rich as petrol.
Ionizing radiation can bring this about by breaking chemical bonds in atoms and molecules.
The purpose was to determine not only what was in the samples in terms of atoms and molecules, but also the precise structures in the interface layer between the original paint and the varnish.
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The primary difference between bitumen and ordinary crude is the size of the hydrocarbon molecules: in liquid oil, these molecules contain between five and twenty carbon atoms, while in bitumen they contain more than twenty. (At room temperature, pure bitumen is so viscous that it will not flow.) The main job of the upgrader is to break down the oversized hydrocarbons into smaller units.
This would involve slipping a few radioactive carbon atoms into molecules of the drugs in question.
Knowing the weights of different sorts of atoms (and of groups of atoms that show up regularly in larger molecules, such as the 20 different amino acids from which proteins are assembled) it is usually possible to piece together fragments to form the profile of an entire protein.
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In the past year, for example, Dr Seddon and Tom Welton, a chemist at Imperial College London, have shown that one of the most important and difficult processes in industrial organic chemistry, the Diels-Alder reaction (which links carbon atoms together and thus allows big molecules to be assembled) can work better in ionic than in conventional solvents.
These free radicals are oxygen-rich molecules in which one of the oxygen atoms is particularly likely to react with other chemicals.
In the end, words and sentences aren't atoms and molecules, even if they can be fodder for the same formulas.
In conventional crystals, such as salt and sugar, these elements are atoms or molecules.
The water molecules' two hydrogen atoms, which are split from oxygen by electrolysis, go in different directions.
The next trick, which Exxon's money will help pay for, is to tweak the biochemical pathway that makes the algal oil (which is known, technically, as a triglyceride, and has oxygen atoms in it as well as carbon and hydrogen) so that the oxygen-containing parts of the molecules are snipped off and a pure hydrocarbon is left.
Like alcohols, fatty acids are molecules that have lots of hydrogen and carbon atoms, and a small amount of oxygen (in their case two oxygen atoms, rather than one).
Between them, they have developed computational methods to crunch the numbers involved in quantum theory in ways that allow chemists to make sense of the behaviour of atoms as they bond together to form molecules.
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