Sunday 23 February 2014

Chemistry Questions

4.) (5 Points) A 1.00 m aqueous solution of the following compounds were produced. Which compound would you expect to produce a solution with the lowest melting point. Assume each compound fully dissolves. a) KClO3 b) MgCl2 c) NaF d) NaCl e) MgSO4
 
 
5.) (5 Points) For the solvents below with their value for Kb (in parenthesis). If a solute is added to each of the solvents to a 1.0 m concentration, which solvent would exhibit the largest change in boiling point? a) Acetic acid (3.07 m-1 ) b) Benzene (2.53 m-1 ) c) Nitrobenzene (5.24 m-1 ) d) Phenol (3.56 m-1 ) e) Water (0.512 m-1 )
 
 
14) (10 points) A 100 mL solution of 0.5 M NaOH is added to 100 mL solution of 0.5 M H2SO4. Determine the pH of the solution. (pKa1 < 0, pKa2 = 1.96). State any necessary assumptions.
 
 
15) (10 Points) Henry's Law constants for aqueous solutions at 25°C are 8.20 × 10-7 molal/mmHg for N2 and 1.62 × 10-6 molal/mmHg for O2.
 
Determine the amount of nitrogen and oxygen (in grams) in a cup (236 mL) of water under an
atmospheric pressure of 760 mmHg, assuming that air is 80% N2 and 20% O2
 
 
16) (10 points) Consider the following reaction at a fixed temperature. 2SO3(g) 2SO2(g) + O2(g) When the initial concentration of SO3(g) is 0.128 M, the concentration of oxygen gas at equilibrium is found to be 0.0130 M. Calculate Kc for this reaction.

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