Water exists as a solid, liquid, and gas on Earth. It is the only substance that naturally exists in all three states within the relatively small range of air temperatures and pressures found at the Earth's surface. How is this property of water central to the planet's dynamics? 1.By changing states, water can evaporate and transpire into the atmosphere. 2.By changing states, water can condense and travel from the atmosphere to Earth's surface. 3.By changing states, water can fall as precipitation that and cause erosion and weathering of Earth's surface. A. 1 only B. 1 and 2 C. 2 and 3 D.1,2 and 3

All the elements are arranged by melting points on the periodic table. in row they go from metals to gasses. in the row from sodium to argon, sodium is more reactive than the one on its right, magnesium.

Answerthis solution will not form a precipitateexplanationsolubility equilbrium:         pbf₂(s)  ⇄ pb²⁺(aq) + 2 f⁻(aq)the solubility product expression is    (we exclude solids from the equilibrium expression).now suppose we have the trial ion product q, which we can define as    then, we can interpret  q as the product of the concentration of the ions that we have and ksp as the product of the ion concentrations that are needed to form a saturated solution.if q > ksp, then that implies that there will be a surplus of ions that exceed the amount that is required to form a saturated solution. a precipitate will then form (the precipitate continually  forms until the surplus ions are removed and q is decreased to ksp's value).if q = ksp, the saturated solution that forms is barely saturated and the precipitate will be minimal.if q < ksp, then the ion concentration will not be enough to form a saturated solution (so no precipitate).using our information, we calculate the trial ion product:     since q = 2.7  × 10⁻⁸ < ksp =  4  ×  10⁻⁸, a precipitate will not form.