Lengths. Practice Exercise 1
Hypothetical elements X and Y form a molecule XYz, in
which both Y atoms are bonded to atom X (and not to one
another). The X-X distance in the elemental form of X is
2.04 Å, and the Y-Y distance in elemental Y is 1.68 Å. What
would you predict for the X-Y distance in the XY2 molecule?
(a) 0.84 Å (b) 1.02 Å (c) 1.86 Å (d) 2.70 Å (e) 3.72 Å

d.) circle motion requires a force to give it a centripetal acceleration.

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%