Mini Chemistry Fossil fuels are unpopular as a source of fuel as large amounts of carbon dioxide and other greenhouse gases are produced during combustion. In order to combat global warming (and reduce the emission of greenhouse gases), it is important to look for alternative fuels. Using Hydrogen as Fuel Hydrogen can be burned in air. Combustion …
Fossil fuels, also known as hydrocarbons, are substances that contain carbon and hydrogen. Examples of fossil fuels: Coal, crude oil (petroleum) and natural gas. Natural gas consists mainly of methane ($\text{CH}_{4}$). Complete combustion of fossil fuels (aka burning of fossil fuels) produces carbon dioxide and water. It is an exothermic reaction. A large amount of heat …
Bond breaking and bond forming occurs during a chemical reaction. The energy changes in chemical reactions are caused by bond breaking and bond forming. Breaking a bond is endothermic. Energy is taken in to break a chemical bond. E.g. $\text{H}-\text{H} \left( \text{g} \right) \rightarrow \text{H}\left( \text{g} \right) + \text{H} \left( \text{g}\right)$, whereby $\Delta \text{H} =+436 …
A chemical reaction that involves a gain of heat energy from the surroundings, resulting in a drop in the temperature of the surroundings is called an endothermic reaction. Summarised version: A reaction that takes in heat from the surroundings. The temperature of the surroundings decreases. (The reaction container becomes colder.) The energy content of the …
A chemical reaction that involves a loss of heat energy to the surroundings, resulting in a rise in the temperature of the surroundings is called an exothermic reaction. Summarised version: A reaction that gives out heat to the surroundings. The surroundings consist of the reaction container, the laboratory room and anything else other than the reactants …