5 Steps to a 5 AP Chemistry

Take a Diagnostic Exam  27

 Answers and Explanations

Chapter 5

1. D—The others form anions.


2. B—Decreasing radii for increasing charges, or for
   going up a column (with equal charges), or
   moving towards the right in a period of the peri-
   odic table. (Note: This explanation would not be
   sufficient for the free response portion of the test.)


3. C—The element that is furthest from F.


4. E—Hexaammine =(NH 3 ) 6 ; cobalt(III) =Co^3 +;
   and nitrate =NO 3 −.


5. D—This was determined by bombarding gold
   foil with alpha particles.

Chapter 6

6. A—All others, except D, are Lewis bases. D is
   neither a Lewis acid nor a Lewis base.


7. A.

3 Mn(OH) 2 (s) +2 H 3 AsO 4 (aq)

→ Mn 3 (AsO 4 ) 2 (s) +6 H 2 O(l)

8. E—PbSO 4 forms.


9. A—[Cu(NH 3 ) 4 ]^2 +forms.


10. C—Fe(OH ) 3 forms.


11. D—Ca(OH) 2 , NaOH, and Na 2 CO 3 are strong
    electrolytes and should be separated. Cancel all
    spectator ions (Na+and OH–).


12. C—The hydroxide took some of the iron with it,
    so Fe^2 +will be low. The nitrate is double the potas-
    sium because there are two nitrates per iron(II)
    nitrate instead of one, as in potassium hydroxide.

Chapter 7

13. C—(0.1000 mol Cr 2 O 72 −/1000 mL) (45.20 mL)
    (6 mol Fe^2 +/1 mol Cr 2 O 72 −)(1/75.00 mL)
    (1000 mL/L)


14. E—Percent Mn in each oxide: (A)77.4; (B) 69.6;
    (C) 72.0; (D) 63.2; (E) 49.5.
    15. A—H 2 C 2 O 4 is the limiting reagent.
    16. A—(0.400 mol Ba)(l mol H 2 /l mol Ba) (22.4 L/mol)

Chapter 8

17. E—This is an application of Charles’s law.


18. D—The heavier gas is moving more slowly.


19. E—The basic difference between ideal and real
    gases.


20. D—(13.5 g Al)(1 mol Al/27.0 g Al)
    (3 mol H 2 /2 mol Al)(22.4 L/mol H 2 )


21. A—The mole fraction of CO times the total pres-
    sure yields the partial pressure. The mole fraction of
    CO is the moles of CO divided by the total moles.


22. A—n =PV/RT =(0.993 atm)(0.237 L)/
    (0.0821 L atm/K mol)(373 K)
    =7.69 × 10 −^3 mol

molar mass =0.548 g/7.69 × 10 −^3 mol

= 71.3g/mol

23. A—The molar mass of the gas must be the square
    of the molar mass of helium.

Chapter 9

24. E—Definition.


25. C—Basic postulate of kinetic molecular theory.


26. A—One of the properties of free energy.


27. B—Definition.


28. B.

ClF(g) +F 2 (g) → ClF 3 (l) −135.1 kJ

−^12 (.)394 1kJ

(^12)
22

[()

() ( )]

Cl O(g)+3 OF g

ClF l O g

22

→+ 32

(^12) (.)−43 5kJ
(^1222)
2

[() ()

()]

Fg O g

OF g

2

2

+

→

(^12) (.)167 5kJ
(^12) [() 2
()]
ClF(g)+O g
Cl O(g)+OF g
2
→ 22

(. 25 )

2

22 4 5

mol H C O

mol

mol

MnSO

HCO

4

22 4

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