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  2. Water-reactive substances - Wikipedia

    en.wikipedia.org/wiki/Water-reactive_substances

    Water-reactive substances [1] are those that spontaneously undergo a chemical reaction with water, often noted as generating flammable gas. [2] Some are highly reducing in nature. [ 3 ] Notable examples include alkali metals , lithium through caesium , and alkaline earth metals , magnesium through barium .

  3. Water cycle - Wikipedia

    en.wikipedia.org/wiki/Water_cycle

    The ocean plays a key role in the water cycle as it is the source of 86% of global evaporation. [2] The water cycle involves the exchange of energy, which leads to temperature changes. When water evaporates, it takes up energy from its surroundings and cools the environment. When it condenses, it releases energy and warms the environment.

  4. Barium - Wikipedia

    en.wikipedia.org/wiki/Barium

    [9]: 2–3 Reactions with water and alcohols are also exothermic and release hydrogen gas: [9]: 3 Ba + 2 ROH → Ba(OR) 2 + H 2 ↑ (R is an alkyl group or a hydrogen atom) Barium reacts with ammonia to form the electride [Ba(NH 3) 6](e −) 2, which near room temperature gives the amide Ba(NH 2) 2. [11] The metal is readily attacked by acids.

  5. Marine biogeochemical cycles - Wikipedia

    en.wikipedia.org/wiki/Marine_biogeochemical_cycles

    Water can be broken down into its constituent hydrogen and oxygen by metabolic or abiotic processes, and later recombined to become water again. While the water cycle is itself a biogeochemical cycle, flow of water over and beneath the Earth is a key component of the cycling of other biogeochemicals. [8]

  6. Thermochemical cycle - Wikipedia

    en.wikipedia.org/wiki/Thermochemical_cycle

    Consequently, a thermochemical cycle with i steps can be defined as sequence of i reactions equivalent to water-splitting and satisfying equations (4), (5) and (10). The key point to remember in that case is that the process temperature T H can theoretically be arbitrary chosen (1000K as a reference in most of the past studies, for high ...

  7. Reactivity series - Wikipedia

    en.wikipedia.org/wiki/Reactivity_series

    Even with this proviso, the electrode potentials of lithium and sodium – and hence their positions in the electrochemical series – appear anomalous. The order of reactivity, as shown by the vigour of the reaction with water or the speed at which the metal surface tarnishes in air, appears to be Cs > K > Na > Li > alkaline earth metals,

  8. Barium hydroxide - Wikipedia

    en.wikipedia.org/wiki/Barium_hydroxide

    Reactions of barium hydroxide with ammonium salts are strongly endothermic. The reaction of barium hydroxide octahydrate with ammonium chloride [18] [19] or [20] ammonium thiocyanate [20] [21] is often used as a classroom chemistry demonstration, producing temperatures cold enough to freeze water and enough water to dissolve the resulting mixture.

  9. Barium carbonate - Wikipedia

    en.wikipedia.org/wiki/Barium_carbonate

    Barium carbonate is the inorganic compound with the formula BaCO 3. Like most alkaline earth metal carbonates, it is a white salt that is poorly soluble in water. It occurs as the mineral known as witherite. In a commercial sense, it is one of the most important barium compounds. [5]