Each substance is characterized by a number of physical and chemical properties on which it can easily be distinguished. At first sight, this knowledge gained within a school course is far from real life. However, we perceive a set of products and materials just on their distinctive properties: to taste, color, smell, density, solubility, hardness. For an example we will consider such recognizable substances as glucose and citric acid.
Let's dwell upon each of these chemical compounds. Glucose – a monosaccharide of natural origin. Meets in fruit, honey, in organisms of animals, plants and the person. Especially there is a lot of glucose in grapes why its second name – glucose. Glucose plays an important role in a metabolism, at hit in an organism stocks up in the form of a glycogen, at plants – in the form of starch. If necessary again breaks up to glucose, participating in power processes of living cells (breath, fermentation, glycolysis). Externally represents crystals of colourless substance, has sweet taste, it is well dissolved in water. Glucose has no expressed smell.
Glucose finds industrial application in the food industry. Its sweet is less, than at sucrose that favorably affects tastes of products. Glucose is added to baby food, confectionery, wine drinks. In the medical purposes it is used for removal of intoxication by means of intravenous administration. Glucose is quickly acquired and restores strength of the person. In endocrinology it is applied to diagnosis of diabetes.
Citric acid – the organic compound which is a part of citrus fruits (lemon, a lime, orange), coniferous plants, tobacco cultures, sour berries. In the environment participates in biochemical reactions of living organisms. In life it is used for strengthening of tastes of ready dishes and fight against a limy raid in a teapot, the iron, the washing machine. At misuse inside can damage tooth enamel, cause allergies, irritation mucous a stomach.
Citric acid finds application as the regulator of acidity and preservative in the food industry. It is used by production of cheeses, carbonated drinks, it is a part of a baking powder. Citric acid is added in medicinal also by cosmetics. On appearance – it is white or slightly yellowish crystal powder. It is distinguished by the expressed sour taste. The smell at citric acid is absent.
As we see, having similar external characteristics, it is easy to distinguish these two substances to taste. Means, even one pronounced sign or property forms a clear picture of what we deal with. Let unconsciously, us regularly use this approach in everyday life: we inhale smells, we taste, we estimate appearance, we heat, we dissolve in water.