a mixture is a physical combination of two or more subtances : heterogeneous mixture we see the various because not combined evenly and homogeneous mixture that cannot see the subtans . .Magnetic separation is a physical method of separating mixtures, which uses the magnetic susceptibility of some of its components. To do this, he resorts to exposing the mixture to a magnet (or a sufficiently strong magnetic field) for a period of time. Decantation is a physical method used for the separation of heterogeneous mixtures, which is used to separate a solid from one or two liquids of different density. It is an important process in wastewater treatment.A chemical reaction is the change of a substance into a new one that has a different chemical identity. The properties of the substance will change.
These changes are produced by an agent such as heat or oxygen.
In this chemical reaction energy is produced in the form of light or heat.
The oxygen from the air reacts with a fuel (wood, petrol or natural gas). Some waste products are produced . Air produces a reaction when the object (normally metals) are in contact with oxygen. They get brown and the surface is covered with rust.
Some foods contain antioxidants
These are substances that prevent oxidation from taking place (antioxidant)
Oxidation is bad for our bodies, because it destroys our cells.This chemical reaction is produced by fungi (yeast) and bacterias. These organisms changes sugar into alcohol or an acid and produce new substances. It is normally used with food to preserve it and stored longer.
Simply put, fermentation is the anaerobic metabolic process that converts sugar into acids, gases, or alcohols. This metabolic process is used in oxygen-deficient environments. Yeast and many other microbes commonly use this process to change their respiration to anaerobic to survive.