Chemistry · Reactivity 1: What drives chemical reactions?. The idea in plain words, the rules to remember, the mistake to avoid and a worked example, written and checked by Mega Lecture.
In complete combustion there is plenty of oxygen. Hydrocarbons and alcohols give carbon dioxide and water; metals and non-metals give their oxides. With too little oxygen, combustion is incomplete and gives carbon monoxide or carbon (soot) with water. Carbon monoxide is toxic and soot damages the lungs.
Fossil fuels store a lot of energy and are easy to transport, but they are non-renewable and release carbon dioxide, a greenhouse gas. Biofuels come from plants that took in carbon dioxide by photosynthesis only recently, so they are renewable and closer to carbon neutral.
A fuel cell turns the chemical energy of a fuel directly into electrical energy, with less waste heat than burning.
When balancing the combustion of an alcohol, students forget the oxygen atom already inside the alcohol and use too much O2. Count the O atoms on the right, subtract those in the fuel, then halve to get O2.
Answer: 2C6H14 + 19O2 → 12CO2 + 14H2O
Type what you are stuck on. The helper finds the explanation, worked examples and the notes to read, free and instant.
← Energy cycles in reactionsHow much? The amount of chemical change →Take a Chemistry test