Prop Manganese and compounds

Manganese is chemical element or on the periodic table it is symbol is Mn. It wwas or protons. It mass number is 54,94. Manganese is a silvery -gray metal and is part of the group known as the transition metals. It is similar to iron. It is hard to mere but easy to oxidite Manganese formy chemical compound in several oxidation stoles: +2,+4 and +7 are the most commin Manganese compounds can be black, brown, pink, red, blue.

Compounds:Manganese(II) chloride,Manganese (IV) oxide, potassium permanganate wswss.

10. Bases -are substances that, in aqueous solution, are slippery to the touch, taste astringent, change the color of indicators (e.g., turn red litmus paper blue), react with acids to form salts, promote certain chemical reactions (base catalysis), accept protons from any proton donor, and/or contain completely or partially displaceable OH⁻ ions. Examples of bases are the hydroxides of the alkali metals and alkaline earth metals (NaOH, Ca(OH)₂, etc.).

An acid is a molecule or ion capable of donating a hydron (proton or hydrogen ion H⁺), or, alternatively, capable of forming a covalent bond with an electron pair (a Lewis acid).^[1]

The first category of acids is the proton donors or Brønsted acids. In the special case of aqueous solutions, proton donors form the hydronium ion H₃O⁺ and are known as Arrhenius acids. Brønsted and Lowry generalized the Arrhenius theory to include non-aqueous solvents. A Brønsted or Arrhenius acid usually contains a hydrogen atom bonded to a chemical structure that is still energetically favorable after loss of H⁺

 

11. An oxide /ˈɒksaɪd/ is a chemical compound that contains at least one oxygen atom and one other element^[1] in its chemical formula. Metal oxides typically contain an anion of oxygen in the oxidation state of −2. Most of the Earth's crust consists of solid oxides, the result of elements being oxidized by the oxygen in air or in water. Hydrocarbon combustion affords the two principal carbon oxides: carbon monoxide and carbon dioxide. Even materials considered pure elements often develop an oxide coating. For example, aluminium foil develops a thin skin of Al₂O₃ (called a passivation layer) that protects the foil from further corrosion.^[2] Individual elements can often form multiple oxides, each containing different amounts of the element and oxygen. In some cases these are distinguished by specifying the number of atoms as in carbon monoxide and carbon dioxide, and in other cases by specifying the element's oxidation number, as in iron(II) oxide and iron(III) oxide. Certain elements can form many different oxides, such those of nitrogen.

 

12. Hydrogen (H) (relative atomic mass: 1.00794) has three naturally occurring isotopes, sometimes denoted ¹H, ²H, and ³H. The first two of these are stable while ³H has a half-life of 12.32 years. All heavier isotopes are synthetic and have a half-life less than one zeptosecond (10⁻²¹ second). Of these, ⁵H is the most stable, and ⁷H is the least.

Hydrogen is the only element whose isotopes have different names that are in common use today. The ²H (or hydrogen-2) isotope is usually called deuterium, while the ³H (or hydrogen-3) isotope is usually called tritium. The symbols D and T (instead of ²H and ³H) are sometimes used for deuterium and tritium. The IUPAC states in the 2005 Red Book that while the use of D and T is common, it is not preferred because it can cause problems in the alphabetic sorting of chemical formulae. The ordinary isotope of hydrogen, with no neutrons, is sometimes called "protium". (During the early study of radioactivity, some other heavy radioactive isotopes were given names, but such names are rarely used today.)

 

22. The water cycle, also known as the hydrological cycle or the H₂O cycle, describes the continuous movement of water on, above and below the surface of the Earth. The mass of water on Earth remains fairly constant over time but the partitioning of the water into the major reservoirs of ice, fresh water, saline water and atmospheric water is variable depending on a wide range of climatic variables. The water moves from one reservoir to another, such as from river to ocean, or from the ocean to the atmosphere, by the physical processes of evaporation, condensation, precipitation, infiltration, surface runoff, and subsurface flow. In doing so, the water goes through different phases: liquid, solid (ice) and vapor.

The water cycle involves the exchange of energy, which leads to temperature changes. For instance, when water evaporates, it takes up energy from its surroundings and cools the environment. When it condenses, it releases energy and warms the environment. These heat exchanges influence climate.

The evaporative phase of the cycle purifies water which then replenishes the land with freshwater. The flow of liquid water and ice transports minerals across the globe. It is also involved in reshaping the geological features of the Earth, through processes including erosion and sedimentation. The water cycle is also essential for the maintenance of most life and ecosystems on the planet.

 

 

32. Phosphorus is a chemical element with symbol P and atomic number 15. As an element, phosphorus exists in two major forms—white phosphorus and red phosphorus—but because it is highly reactive, phosphorus is never found as a free element on Earth. At 0.099%, phosphorus is the most abundant pnictogen in the Earth's crust. With few exceptions, minerals containing phosphorus are in the maximally oxidised state as inorganic phosphate rocks.

Phosphorus is essential for life. Phosphates (compounds containing the phosphate ion, PO₄³⁻) are a component of DNA, RNA, ATP, and the phospholipids, which form all cell membranes. Demonstrating the link between phosphorus and life, elemental phosphorus was first isolated from human urine, and bone ash was an important early phosphate source. Phosphate mines contain fossils, especially marine fossils, because phosphate is formed from the deposits of animal remains and excreta. Low phosphate levels are an important limit to growth in some aquatic systems. The vast majority of phosphorus compounds produced are consumed as fertilisers. Phosphate is needed to replace the phosphorus that plants remove from the soil, and its annual demand is rising nearly twice as fast as the growth of the human population. Other applications include the role of organophosphorus compounds in detergents, pesticides, and nerve agents.

 

14. Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table and is a highly reactive nonmetal and oxidizing agent that readily forms oxides with most elements as well as other compounds. By mass, oxygen is the third-most abundant element in the universe, after hydrogen and helium. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula O
2. This is an important part of the atmosphere and diatomic oxygen gas constitutes 20.8% of the Earth's atmosphere. Additionally, as oxides the element makes up almost half of the Earth's crust.

Oxygen occurs as an elementary substance in two allotropic varieties: the natural oxygen (second constituent of the air) and the ozone. It also forms a great variety of compounds and, in the combined state, it is the most abundant element of the terrestrial crust (in the silica and silicates form) and of the oceans (in water).

Oxygen reacts with some complex transition metals which act as transporters of the substance, i.e., they capture and give O2 in a reversible way. Some of these complex metals constitute prosthetic groups of indispensable proteins to the metabolic process of breathing. That is the case of the hemoglobin and of certain hemocyamines that are natural carriers of oxygen.

15. Oxygen is what is known as a highly reducing gas: it likes to combine with other molecules like atmospheric gases or surface rocks. It is the second-most electronegative atom in the periodic table after flourine; this means that oxygen has a strong tendency to rip electrons from other atoms. As a consequence, any given oxygen molecule has a relatively short lifetime in the atmosphere. Before the rise of photosynthesis, a process which produces oxygen and continues to this day to replenish our supply, Earth's atmosphere had no appreciable quantity of oxygen whatsoever.