[2cool4wrds]

THREE QUESTIONS: (The == is a bond)
(Can you show me how to solve these problems?)
1. Argon makes up 0.93% by volume of air.  Calculate its solubility (mol/L) in water at 20C and 1.0atm.  The Henry’s law constant for Ar under these condition is 1.5 x 10 ^-3 mol/L*atm.

2. Respiratory problems are treated with devices that deliver air with a higher partial pressure O2 than normal air.  Why? 

3. How would you prepare the following aqeuous solutions? (I don't even understand the question)
(a) 3.5L of 0.55 M NaCl from solid NaCl
(b) 17.5 L of 0.3 M urea [(NH2)2C==O] from 2.2 M urea.