What's the difference between water, pure water, fresh water and pure water?

The difference and connection between the four lies in:

Water (chemical formula: H2O) is an inorganic substance composed of hydrogen and oxygen, and it is a colorless and odorless transparent liquid at normal temperature and pressure. It means pure water or pure water, which means the same thing.

However, in our language habits in China, what we usually call water sometimes refers to pure water, and sometimes refers to water with impurities stored in rivers, lakes or oceans, that is, natural water (rivers, lakes, atmospheric water, seawater, groundwater, etc.). ) mentioned upstairs, or other water containing impurities. No matter what kind of water it is, its main body or most of it should be water, followed by other impurities.

Fresh water refers to water with a salt content of less than 0.5 g/L. Generally, all water in rivers and lakes is fresh water. However, seawater or salt lake water is not fresh water because of its high salt content. But modern technology can extract fresh water from seawater through purification.

Supplementary information: Water includes natural water (rivers, lakes, atmospheric water, seawater, groundwater, etc. ) and artificial water (water is a combination of hydrogen atoms and oxygen atoms through chemical reactions). Water (chemical formula: H2O) is an inorganic substance composed of two elements, hydrogen and oxygen, which exists in three aggregation states in nature: solid, liquid and gas. It is a colorless and odorless transparent liquid at normal temperature and pressure. Water is one of the most common substances on the earth, an important resource for all life, including human beings, and the most important component of organisms. Water plays an important role in the evolution of life. People's understanding of aquatic products has a long history. In China's ancient and western simple material views, water was regarded as the basic component, and water was one of the five elements in ancient China. There was also water in the four-element theory of ancient western countries.

Pure water refers to H2O without impurities. Academically speaking, pure water is also called high purity water and deionized water. Refers to water with high chemical purity, which is mainly used in biology, chemistry, metallurgy, aerospace, electric power and other fields, but it requires high purity of water quality, so it is most commonly used in electronics industry. The national standards for high purity water are GB1146.1-89 to GB1146.1-89 [168]. ASTM At present, China's high-purity water standard divides electronic-grade moisture into five grades:

Fresh water is water with a salt content of less than 0.5g/L.. Water with salinity less than or equal to 1000 mg/L.

Pure water refers to drinking water treated by reverse osmosis and deionized water, and its conductivity is (25 1℃) μ s/cm ≤ 10.

Simply put, water is the liquid of water, and pure water is water without impurities, which is generally used in laboratories and precision industrial production. Fresh water is water without salty taste, and pure water is the purest water in drinking water.

Water includes natural water (rivers, lakes, atmospheric water, seawater, groundwater, etc.). ) and artificial water (water is a combination of hydrogen atoms and oxygen atoms through chemical reactions). Water (chemical formula: H2O) is an inorganic substance composed of hydrogen and oxygen, and it is a colorless and odorless transparent liquid at normal temperature and pressure. Water is one of the most common substances on the earth, an important resource for all life, including human beings, and the most important component of organisms.

Pure water, also known as pure water and deionized water, refers to the water that meets the hygienic standard for drinking water, is sealed in a container, contains no additives, is colorless and transparent, and can be directly drunk by appropriate treatment methods such as electrodialysis, ion exchange, reverse osmosis and distillation. It can also be called pure substance (chemically), which is widely used in experiments. Because it is made by distillation, it is also called distilled water. Space water and distilled water sold in the market are pure water; But it is better to drink less pure water, because the human body needs few minerals. Pure water is not easy to conduct electricity and is an insulator. Pure water should be used when replenishing water for lead-acid batteries.

Fresh water is water with salt content less than 0.5 g/L, and the total amount of water on the earth is 65.438+0.4 billion cubic kilometers. There is a lot of water on the earth, and the fresh water reserves only account for 2.53% of the world's total water, of which 68.7% belong to solid glaciers, which are distributed in mountainous areas and the hard-to-use north and south poles. Some fresh water is buried deep underground and it is difficult to exploit.

Pure water refers to H2O without impurities. Academically speaking, pure water is also called high purity water, which refers to water with high chemical purity. It is mainly used in biology, chemistry, metallurgy, aerospace, electric power and other fields, but it requires high purity of water, so it is most commonly used in electronics industry.