How many moles of water are in 249.6g of hydrated copper sulfate(VI) (CuSO 4 .5H 2 O)?

1) Total mass of the compound: 
  = CuSO₄ * 5H₂O
 = 63.5 + 32 + 16*4 + 5[1 * 2 + 16]
 = 95.5 + 64 + 90
 = 249.5 amu

b) Mass of water in compound = 5H2O = 5 [1 * 2 + 16] = 90 amu

c) Percentage of water = 90/249.5 * 100 = 36.07%

29) We know, Equation of Charles law:
 V1T1 = V2T2
Here, V1 = 725 mL
T1 = -35 + 273 = 238 K
T2 = 25 + 273 = 298 K

Substitute their values, 
725*238 = v2*298
v2 = 172550 / 298
v2 = 579.02 mL

30.) At higher altitudes, Atmospheric pressure is very lower, so foods take longer to cook. In order to save some time due to such a low pressure, there are some instructions for that.

Hope this helps!