Why does ca react with water

Contrary to magnesium placed directly above calcium in the periodic chart, elementary calcium reacts with water at room temperature, according to the following reaction mechanism:. Other important calcium reaction mechanisms are erosion reactions. These usually occur when carbon dioxide is present. Under normal conditions calcium carbonate is water insoluble. When carbon dioxide is present carbonic acid is formed, affecting calcium compounds.

Solubility of calcium and calcium compounds Elementary calcium reacts with water. Calcium compounds are more or less water soluble. Why is calcium present in water?

Calcium is naturally present in water. It may dissolve from rocks such as limestone, marble, calcite, dolomite, gypsum, fluorite and apatite. Magnesium is the other hardness determinant. Calcium is present in various construction materials, such as cement, brick lime and concrete. It is present in batteries, and is applied in plaster as calcium sulphate.

The metal is applies for zirconium and thorium production. In steal industries calcium is applied as a blotter, and is added to aluminium , copper and lead alloys.

Calcium can extract sulphur dioxide from industrial exhaust, and neutralize sulphuric acids before discharge. Other examples of calcium applications are calcium hypo chloride as bleach and for disinfection, calcium phosphate in glass and porcelain industries, calcium polysulphide and hydroxide as flocculants in wastewater treatment, and calcium fluoride as turbidity agent in enamel industries, in UV-spectroscopy, and as a raw material for fluid acid production.

Calcium may also be applied for removal of carbon and sulphur from iron and iron alloys, and for dewatering oil. Limestone is applied as a paper filler, causing paper to colour whiter, and in plastics to improve stability. Calcium often positively affects soil quality and various compounds are applied as a fertilizer. Calcium oxide is a dehydrating molluscicide. Calcium is a dietary requirement for all organisms apart from some insects and bacteria.

Calcium carbonate is a building stone of skeletons of most marine organisms, and eye lenses. Calcium phosphate is required for bone structure and teeth structure of terrestrial organisms. Plants mainly contain calcium oxalate. Calcium is largely responsible for water hardness, and may negatively influence toxicity of other compounds.

Elements such as copper, lead and zinc are much more toxic in soft water. Calcium starts floating because the bubbles of hydrogen gas which are formed during the reaction stick to the surface of the metal and hence calcium floats on water. Answer: This reaction is a combination reaction as calcium oxide and water combines to form a single product that is calcium hydroxide. Calcium floats on water because the bubbles of hydrogen gas formed by the reaction of calcium with water stick to the surface of metal.

But all metals do not react with water. Magnesium does not react with cold water. It reacts with hot water to form magnesium hydroxide and hydrogen. Sodium also floats on the surface, but enough heat is given off to melt the sodium sodium has a lower melting point than lithium and the reaction produces heat faster and it melts almost at once to form a small silvery ball that dashes around the surface…. Calcium, for example, reacts fairly vigorously with cold water in an exothermic reaction.

Bubbles of hydrogen gas are given off, and a white precipitate of calcium hydroxide is formed, together with an alkaline solution also of calcium hydroxide — calcium hydroxide is slightly soluble. The bubbles formed stick to the surface of calcium metal and make it lighter. Therefore, Calcium floats on water.

Calcium is a silvery-white metal; it is relatively soft, but much harder than sodium metal. Calcium is a member of the alkaline-earth metals Group II on the periodic table ; these metals react vigorously with water, although not as violently as the Group I metals such as sodium or potassium:.

In the following demonstration, a chunk of calcium metal is dropped into a beaker of distilled water. After a second or so, the calcium metal begins to bubble vigorously as it reacts with the water, producing hydrogen gas, and a cloudy white precipitate of calcium hydroxide. The presence of the hydroxide is demonstrated by the addition of a few drops of phenolphthalein indicator, which turns the solution pink, indicating that the solution is basic.