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Thursday 26 January 2012

Chemistry Assignment Help Questions and Answers part2

1. A solution of 8.0 M formic acid (HCOOH) is 0.47% ionized.
What is the K of formic acid?
A) 3.4 x 10-8 B) need more data C) 1.8 X 10-4 D) 6.9 X 10-6 E) 3.8 x 10-2

2. The [OH-] in a 0.50 M pyridine (C5H5N; Kb = 1.7 X 10-9) solution is
A) 0.50 M B) 2.9 x 10-5 M C) 1.8 x10-9 M D) 3.3 x 10-10 M E) none of these

Use the following to answer question 3:
3.5 x 102 mL of3.2 M Pb(N03)2 and 2.0 x 102 mL of 0.020 M NaCl are added together. Kso for the lead chloride is1.6 x 10^-5.

3. What is the limiting reagent in the formation of the lead chloride?
A) Pb(N03)2 B) PbCl2 C) Pb2 D)(N03)- E)

4. For carbonic acid (H2C03)' Kal = 4.30 x 10-7 and Ka2=5.62 x 10-11. Calculate the pH of a 0.50 M solution Na2C03'
A) 10.67 B) 11.97 C) 8.31 D) 3.33 E) 2.03

5. Consider the titration of 100.0 mL of 0.100 M H2A (Kal = 1.50 x 10-4;
Ka2= 1.00 x 10-8). How many milliliters of 0.100M NaOH must be added to reach a pH of 5.000?
A) 100. mL
B) 93.8 mL
C) 200.mL
D) 60.0mL
E) 41.9 Ml
6. Which of the following compounds has the lowest solubility in mollL in water?
A) K = B) PbS04 K = 1.3 x 10-8soC) Sn(OH)2 K = 3 x 10-27SD
D) MgC20" K = 8.6 x 10-54...i' "'T soE) CdS K = 1.0 x 10-28so

(7) The equilibrium constant of a certain reaction was measured at various temperatures to give the plot shown above. What is llSO for the reaction in J/mo! . K?( Refer original for graph)
A) 0.20
B) -8.3 x 103
C) 3.0
D) 25
E) -50.

8. The molar solubility of PbI2 is 1.5 x 10-3 M. Calculate the value of Kso for PbI2
A) 2.3 x 10-6 B) 3.4 x10-9 C) 1.5 x 10-3 D) 1.4 x 10-8 E) none of these

9. Find the solubility (in mollL) of lead chloride (PbC12) at 25°C. Kso = 1.6 x 10-5
A) 0.020 B) 2.1 C) 1.6 x10-2 D) 9.3 x 10-3 E) 7.1 x 10-5

Use the following to answer question 10:

The following three equations represent equilibria that lie far to the right.
HNO3~(aq) + CN-(aq) ~ HCN(aq) +N03-(aq)
HCN(aq) + OH-(aq) ~ H20(!) + CN-(aq)
H20(!) +CH30-(aq) ~ CH20H(aq) +OH-(aq)

10. Identify the strongest acid.
A) H20 B) HN03 C) OH- D) CH30H E) HCN
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Chemistry Assignment Help Questions part1 available at http://goo.gl/HCCXC
Chemistry Assignment Help Questions part3 available at http://goo.gl/5xWvB
Chemistry Assignment Help Questions part4 available at http://goo.gl/vUSSx