The molecules of one reactant are combined with those of another reactant to form a new substance during a chemical reaction. As the chemical bonds are broken, the positions of electrons change, resulting in a product with properties that are different from the properties of the reactants. Various temperatures and catalysts are needed for different chemical reactions to occur.Know More
In a chemical reaction, there is a change of electrons, but there is no change of nuclei. Therefore, the elements present in the product of the reaction are still the same as the elements in its original reactants. There are chemical reactions that take place spontaneously without the input of extra energy, while others need the addition of heat, light or electricity.
A basic example of a chemical reaction is the combustion of a candle, in which oxygen combines with molecules of the wax to melt it into a new product. Similarly, the process of fermentation and the reduction of mineral ores into metals are well-known chemical reactions. A chemical reaction can easily be perceived through the senses because it involves emission of considerable heat, light and gas. In addition, the process forms a precipitate, which features a color that is different from the reactants. Basic chemical reactions involve the combination of harmless elements, while major chemical reactions involve reactants that are often violent and destructive.Learn more in Chemistry
The chemical reaction for fermentation is expressed as the chemical equation: C6H12O6 ? 2 C2H5OH + 2 CO2. Showing the alcoholic fermentation of glucose as chemical formula C6H12O6, this one glucose molecule is converted into two ethanol molecules expressed as 2C2H5OH and two carbon dioxide molecules expressed as 2CO2.Full Answer >
A chemical reaction can be shown to be endothermic if it absorbs heat and causes a decrease in the temperature of its surroundings. Illustrative lab experiments performed in schools to demonstrate endothermic reactions often use the reaction occurring between vinegar and baking soda or the reaction between barium hydroxide and ammonium nitrate. The latter reaction, if taking place in a flask resting in a small amount of water, will absorb enough heat from the water to cause it to freeze.Full Answer >
The chemical reaction between aluminum and bromine is an exothermic one that produces aluminum bromide. The equation of the chemical reaction is 2 Al + 3 Br2 ? 2 AlBr3. It indicates that two molecules of aluminum combine with three molecules of bromine to produce two molecules of aluminum bromide.Full Answer >
There are a few telltale signs that can help indicate that a chemical reaction has taken place; these include the creation of one or more new substances and a noticeable energy change from the reaction site. However, telling whether a chemical reaction has actually taken place is not always very easy to observe.Full Answer >