Is combining hydrogen and oxygen an exothermic reaction and what type of reaction has one element and one compound as reactants?
The reaction between hydrogen and oxygen is exothermic- it releases energy to the surroundings: hydrogen + oxygen → water 2H2 + O2 → 2H2O Fuel cells use the reaction between a fuel and oxygen to produce electrical energy. The reaction of hydrogen with oxygen to form water is an exothermic reaction. In the reaction, the hydrogen molecules are oxidized and the oxygen atoms are reduced. Hydrogen and oxygen are at a higher energy level than the products of the reaction. This results in the net release of energy from the reaction, and this is known as an exothermic reaction. When molecular hydrogen (H2) and oxygen (O2) are combined and allowed to react together, energy is released and the molecules of hydrogen and oxygen can combine to form either water or hydrogen peroxide. Chemical reactions: combination. In a combination reaction the atoms and/or molecules do what the name implies: they combine to form the product. Combination reactions are always exothermic. (a) Combination reactions occur when two or more substances combine to producece a single substance or product, or when two reactants combine to form a single product. (b) Burning of carbon in presence of oxygen to produce carbon dioxide is an example of a combination reaction which is also an exothermic reaction. A single replacement reaction, sometimes called a single displacement reaction, is a reaction in which one element is substituted for another element in a compound. The starting materials are always pure elements, such as a pure zinc metal or hydrogen gas, plus an aqueous compound. A synthesis reaction occurs when two or more reactants combine to form a single product. In a decomposition reaction, one reactant breaks down into two or more products. This is the reverse of a synthesis reaction. Replacement reactions occur when elements switch places in compounds. One combination reaction is two elements combining to form a compound. Solid sodium metal reacts with chlorine gas to produce solid sodium chloride. If a chemical reaction occurs with two elements as reactants a synthesis reaction could occur. A synthesis reaction occurs when two molecules share or exchange electrons to form one new molecule.