Download Unit 12 Worksheet Answers

Name_______________________________________________period__________Unit 13: concentrations
1. Write the equation for the dissociation of each of the following.
a. Potassium iodide
b. sodium nitrate
c. magnesium chloride
+
+
KI K + I
NaNO 3  Na + NO 3
MgCl 2  Mg2+ + 2Cl-
d. aluminum sulfate
Al 2 (SO 4 ) 3  2Al3+ + 3SO 4 2-
2. For the previous problem, determine the total number of ions produced in each.
a.
2
b. 2
c. 3
d. 5
3. What is the difference between a nonelectrolyte, a strong electrolyte and a weak electrolyte?
Nonelectrolyte does not conduct electricity (no ions)
Weak electrolyte conducts electricity a little (little ions)
Strong electrolyte conducts electricity well (a lot of ions)
4. What is the difference between a strong acid and a weak acid?
Strong acids completely ionize (a lot of ions in soln) and weak acid only partially ionize (a little bit on ions in soln)
5. Label each as a strong acid or weak acid and name them
a. HCl
b. HNO 2
c. HC 2 H 3 O 2
d. HClO 3
e. HClO
f. H 2 SO 4
g. HF
Hydrochloric acid nitrous acid acetic acid
chloric acid
hypochlorous sulfuric hydrofluoric
Strong
weak
weak
strong
weak
strong
weak
6.
Write the formula for each acid and label if they are strong or weak
a. Phosphoric acid
b. Sulfurous acid
c. Hydrobromic acid
H 3 PO 4
H 2 SO 3
HBr
Weak
weak
strong
7. Label each as a nonelectrolyte, weak electrolyte, or strong electrolyte
KCl
b. AgCl
c. HF
Strong
weak
weak
e. H 2 S
H2S
weak
d. NO 2
non
f. Ba(NO 3 ) 2
g. H 2 SO 4
f. CO 2
strong
strong
non
g. Al(OH) 3
h. H 3 PO 4
i. PbSO 4
weak
weak
weak
strong
k. LiOH
l. HClO
m. C 6 H 12 O 6
n. HCl
strong
weak
non
strong
weak
d. hydrosulfuric acid
j. HClO 4
8. Which of the following will have all ions in solution?
a. HBr
b. Na 2 SO 4
c. HNO 2
d. Mg(OH) 2
e. HNO 3
9. Which of the following will have a few ions in solution?
a. HBr
b. Na 2 SO 4
c. HNO 2
d. Mg(OH) 2
e. HNO 3
10. Which of the following will have no ions in solution?
a. HBr
b. Na 2 SO 4
c. HNO 2
d. Mg(OH) 2
e. HNO 3
11. What precipitate will form when solutions of barium nitrate and sodium hydroxide react?
No precipitate
12. What precipitate will form when sodium chloride and silver nitrate react?
Silver chloride
d. CO 2
d. CO 2
d. CO 2
13. Write the net ionic reactions for the following
22+
a. Sodium sulfate is added to strontium nitrate SO 4 + Sr  SrSO4
33+
b. Potassium phosphate is added to aluminum chloride PO 4 + Al  AlPO 4
+
c. nitric acid is added to sodium hydroxide H + OH  H 2 O
14. What is the molality of a solution if 3.4 mol of hydrochloric acid is dissolved in 2.3 kg of water? 1.4 m
15. What is the molality of a solution if 294.3 g of sulfuric acid is dissolved in 0.25 kg of water?
12 m
16. A solution is made by dissolving 17.1 g of sucrose, C 12 H 22 O 11 in 275 g of water.
a. What is the solute? Sucrose
b. What is the solvent? water
c. What is the molality? 0.182 m
17. What is the van’t hoff factor (how many ions does it turn into) for each of the following?
b. NaOH
c. Mg(NO 3 ) 2
d. HF
e. HCl
a. NH 3
1
2
3
1
2
f. Na 3 PO 4
4
18. Put the following 2 molal solutions in order of increasing boiling points Mg(NO 3 ) 2 , NH 3 , Na 3 PO 4 , NaCl.
NH 3, NaCl, Mg(NO 3 ) 2, Na 3 PO 4
19. Put the following 2 molal solutions in order of increasing freezing points MgCl 2 , HF, NaOH, Al 2 (SO 4 ) 3
Al 2 (SO 4 ) 3, MgCl 2, NaOH, HF
20. What is the boiling point and freezing point of a solution, if 4.5 mol of sugar are dissolved in 2 kg of water?
-4.19 C= fp
101.1 C= bp
21. What is the boiling point and freezing point of a solution, if 4.5 mol of magnesium chloride are dissolved in 2 kg of water?
Fp= -12.6 C
Bp = 103.4 C
22. What is the freezing point of a solution if 15 g of carbon tetrachloride is dissolved in 250 g of benzene?
Fp = 2.52 C
23. If 0.500 mol of a nonelectrolyte solute is added to 500.0 g of ether, what is the freezing point of the solution?
-118.1 C
24. What is the freezing point of a 0.015 m barium nitrate solution?
-0.084 C
25. If 2 moles of magnesium sulfate are dissolved in 1.00 kg of water, what is the freezing point of the solution?
-7.44 C
26. Determine the boiling point of a solution made by dissolving 4.5 mol of aluminum sulfate in 450 g of water.
125.5 C
27. How much more effective is aluminum sulfate than a nonelectrolyte at raising the boiling point of a solution?
Five times more effective
28. How much more effective is magnesium chloride than a nonelectrolyte at lowering the freezing point of a solution?
Three times more effective
Review:
29. Define the term isotope.
Same element with different masses (same number protons, different number of neutrons)
30. Does an electron need to absorb energy or give off energy to go from the 2nd to the 1st energy level?
Give off
31. Given the following compounds, determine the charge on the unknown ion “X”.
b) MgX
c) X 3 P 2
a) X 2 S
+1
-2
+2
32. Complete the following reaction: 6Li + Ca 3 (PO 4 ) 2  2Li 3 PO 4 + 3Ca
33. Balance the following reaction: _____ Al 2 S 3 + _3____ Cu  __3___ CuS + __2___ Al
34. Find the formula mass for each of the following (include units):
a) magnesium phosphide
b) sodium sulfate
134.9 g/mol
142 g/mol
35. In a bag full of pennies, you may have 2.15 moles of copper. How many grams do you have?
137 g
36. Experiments performed to reveal the structure of atoms led scientists to conclude that an atom’s
a. positive charge is evenly distributed throughout its volume
b. negative charge is mainly concentrated in its nucleus
c. mass is evenly distributed throughout its volume
d. volume is mainly unoccupied
37. As an atom becomes an ion, its mass number
a. decreases
b. increases
c. remains the same
38. What is the nuclear charge of an iron atom?
a. +26
b. +36
c. +56
d. +82
39. Which of the following elements has the strongest attraction for electrons?
a. boron
b. aluminum
c. oxygen
d. sulfur
40. As the elements in Group 17 are considered in order of increasing atomic number, the chemical reactivity of each
successive element:
a. decreases
b. increases
c. remains the same
41. Element X is in Group 2 and element Y is in Group 17. What happens when a compound is formed between these
two atoms?
b. X loses electrons to Y to form a covalent bond.
a. X loses electrons to Y to form an ionic bond.
c. X gains electrons from Y to form an ionic bond.
d. X gains electrons from Y to form a covalent bond.
42. Given the reaction 2Al + 3FeO  Al 2 O 3 + 3Fe; what is the mole to mole ratio between iron (II) oxide and aluminum oxide?
a.
2:3
b. 1:1
c. 3:2
d. 3:1
43. Which pair is most likely to form an ionic bond?
a.
b.
Carbon and sulfur
magnesium and fluorine
c. aluminum and magnesium
d. hydrogen and chlorine
44. Which describes a system that has reached chemical equilibrium?
a.
b.
c.
d.
No new product is formed by the forward reaction.
The reverse reaction no longer occurs in the system.
The concentration of reactants in the system is equal to the concentration of products.
The rate at which the forward reaction occurs equals the rate of the reverse reaction.