Explanation:
The 'ozone hole' is most prominent over Antarctica during spring due to unique polar stratospheric clouds and CFC accumulation. Arctic ozone depletion also occurs but is less severe.
Explanation:
Froth flotation is used to concentrate sulfide ores. Galena (PbS) is a sulfide ore; it is wetted by oil (pine oil) and comes to the surface with froth, while gangue particles wetted by water settle down. Bauxite (Al₂O₃·2H₂O) is an oxide ore concentrated by leaching (Bayer's process). Magnetite (Fe₃O₄) is magnetic ore separated by magnetic separation. Carnallite (KCl·MgCl₂·6H₂O) is a halide ore.
Explanation:
Dalton's atomic theory (1808) provided a framework for the laws of chemical combination—conservation of mass, constant composition, and multiple proportions. The law of multiple proportions states that when two elements form more than one compound, masses of one that combine with fixed mass of the other are in small whole number ratios. Dalton proposed atoms combine in simple whole number ratios to form compounds.
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