Which half-reaction correctly describes an oxidation?
Upper C a (s) plus 2 e superscript minus right arrow upper C a superscript 2 plus (a q).
Upper B r subscript 2 plus 2 e superscript minus right arrow 2 upper B r superscript minus.
Upper N a superscript plus (a q) right arrow upper N a (s) plus e superscript minus.
Upper C r (s) right arrow upper C r superscript 3 plus (a q) plus 3 e superscript minus.

d. temperate deciduous forest

why is arctic sea ice important? arctic sea ice keeps the polar regions cool and moderate global climate. sea ice has a bright surface; 80 percent of the sunlight that strikes it is reflected back into space. as sea ice melts in the summer, it exposes the dark ocean surface.

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%