How many grams of water react to form 4.50 moles of Mg(OH)2?
MgO(s) + H20(1)
Mg(OH)2(s)

mass of water is 81.1 g

Explanation: from reaction eguation you see there are equal amounts of water and Mg(OH)2. Then amount of water is 4.50 mol. Molar mass of water is 18.016 g/mol.

Mass m= n·M= 4.50 mol· 18.016 g/mol = 81.1 g

the cold front replaces the warmer air at the ground level changing the wind to be breezy and denser.there is also an immediate drop in the temperature.