answr. Magnesium and water...Formula= magnesium + water --> magnesium hydroxide + hydrogenThe magnesium floats on the surface, this is a slow reaction but … However, its reaction with cold water produces magnesium hydroxide and hydrogen gas. Magnesium is a very light metal that belongs to group two of the periodic table, and it has an atomic number of 12. An exothermic reaction is a term that describes a chemical reaction in which there is a net release of energy (heat). Similarly, calculating the enthalpy changes for the reactions between calcium, strontium or barium and cold water reveals that the amount of heat evolved in each case is almost exactly the same—about -430 kJ mol -1 . However, only the magnesium reaction actually happens. Burning magnesium ribbon is plunged into the steam above boiling water in a conical flask. In the first method, the hydrogen that is formed is allowed to burn at the mouth of the flask. It does however react with steam, forming magnesium oxide, MgO, or magnesium hydroxide, Mg(OH) 2, with excess steam, and hydrogen gas (H 2). And for hot water it is: Mg + 2H2O ->Mg(OH)2 + H2 But when steam is used, the magnesium burns to produce magnesium oxide and hydrogen. Upvote(3) How satisfied are you with the answer? The explanation for the different reactivities must lie somewhere else. toppr. Magnesium reacts with water to produce hydrogen and a lot of heat. Mg (s) + H 2 O (g) MgO (aq) + H 2 (g) Beryllium. Magnesium does not react with liquid water at room temperature. This will help us to improve better. Hence the explosion when water is added to burning magnesium. Answered By . A. Metallic magnesium reacts only slowly, but magnesium vapour, produced when Mg burns, reacts extremely quickly due to the high temperature and efficient mixing, and produces heat very rapidly. Reaction of magnesium with water. The reactions of magnesium are different in case of hot water and steam. It uses these reactions to explore the trend in reactivity in Group 2. For steam it is: Mg + H2O -> MgO + H2. ... M g + 2 H 2 O → M g (O H) 2 + H 2 Magnesium reacts with hot water to form magnesium hydroxide and hydrogen. Get Instant Solutions, 24x7. Hence, the reaction is vigorous in hot water and in steam.Another equally important reason for the vigorous reaction in hot water is that the produced hydrogen gas is more thoroughly expelled from the layer of magnesium than in cold water due to the prevailing turbulence and also as gases are generally less soluble under hot conditions in liquids. In the second method, the hydrogen is collected over water and tested with a lighted spill. Magnesium is a relatively reactive metal. The reaction with cold water is very slow; in real life it would take days to collect and test the gas released. The Facts. This page looks at the reactions of the Group 2 elements - beryllium, magnesium, calcium, strontium and barium - with water (or steam). Magnesium also reacts with many other substances and elements, such as acids, bases, nitrogen, halogens and oxygen. Write the balanced chemical reaction for the reaction of magnesium with hot water.