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In page Gunpowder:

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Gunpowder made with less-expensive and more plentiful sodium nitrate instead of potassium nitrate (in appropriate proportions) works just as well. Gunpowder releases 3 megajoules per kilogram and contains its own oxidant.[citation needed] This is less than TNT (4.7 megajoules per kilogram), or gasoline (47.2 megajoules per kilogram in combustion, but gasoline requires an oxidant; for instance, an optimized gasoline and O2 mixture releases 10.4 megajoules per kilogram, taking into account the mass of the oxygen).