Unit 9 Question Packet Name

Unit 9 Question Packet Name ………………………………………………

Solutions Period ………….

Skills

1. Identifying Solute and Solvent

2. Identifying soluble and insoluble compounds

3. Writing and Balancing Equations for Double Replacement Reactions

4. Understanding Factors that Affect Solubility

5. Determining type of Solution using table G

6. Expressing Concentration in Molarity or PPM

7. Identifying Properties of Solutions

Skill #1: Identifying Solute and Solvent - refer to your notes & RB p. 99-100

1.  Fill in the table below.

Skill #2: identifying Soluble and Insoluble Compounds - refer to your notes and RB p. 103

2. Use Table F to determine if the following compounds are soluble or insoluble.

Skill #3: Writing and Balancing Equations for Double Replacement Reactions - refer to your notes

3. Write the balanced chemical equation for each of the following descriptions.

·  Use Table F to determine the state of the products – (s) or (aq).

·  Write “soluble” or “insoluble” under each reactant and product.

·  Square off the precipitate.

(a)  Solutions of sodium carbonate and silver nitrate are mixed.

Na2CO3 (aq) + 2 AgNO3 (aq) à Ag2CO3(s) + 2 NaNO3 (aq)

soluble soluble insoluble soluble

(b)  AgC2H3O2 (aq) is mixed with NaCl (aq).

AgC2H3O2 (aq) +NaCl (aq) à AgCl (s) + NaC2H3O2 (aq)

soluble soluble insoluble soluble

(c)  Solutions of potassium sulfate and calcium chlorate are mixed.

K2SO4 (aq) + Ca(ClO3)2 (aq) à 2 KClO3 (aq) + CaSO4 (s)

soluble soluble soluble insoluble

(d)  CaCl2 (aq) and Na2S (aq) are mixed.

CaCl2 (aq) + Na2S (aq) à CaS (s) + 2 NaCl (aq)

soluble soluble insoluble soluble

(e)  What do all the above double replacement reactions have in common?

They start with two compounds and end with two compounds

Skill #4: Understanding Factors that Affect Solubility - refer to your notes & RB p. 102

4. Check the conditions under which each of the following solutes will be most soluble. Look at Table G for help.

5. Naphthalene, a nonpolar substance that sublimes at room temperature, can be used to protect wool clothing from being eaten by moths.

a.  Explain, in terms of intermolecular forces, why naphthalene sublimes. [1]

b.  Explain why naphthalene is not expected to dissolve in water. [1]

c.  The empirical formula for naphthalene is C5H4 and the molecular mass of naphthalene is 128 grams/mole. What is the molecular formula for naphthalene? [1]

a.  Naphthalene has weak intermolecular forces

b.  Naphthalene is nonpolar; water is polar.

Nonpolar won’t dissolve in polar.

Like dissolves like.

c.  C10H8 or H8C10

Skill #5: Determining Type of Solution using Table G - refer to your notes & RB p.104-107

6. State whether each of the following solutions is saturated, unsaturated, or supersaturated.

(a) 80 g NaNO3 in 100 g H2O at 10ºC ______saturated

(b) 75 g NaNO3 in 100 g H2O at 10ºC ______un

(c) 90 g NaNO3 in 100 g H2O at 10ºC ______super

(d) 90 g KNO3 in 100 g H2O at 50ºC ______super

(e) 90 g KI in 100 g H2O at 50ºC ______un

(f) 5 g KClO3 in 100 g H2O at 5ºC ______saturated

(g) 40 g KCl in 50 g H2O at 60ºC ______super

(h) 35 g NaNO3 in 50 g H2O at 10ºC ______un

(i) 5 g KClO3 in 50 g H2O at 5ºC ______super

(j) 5 g KClO3 in 200 g H2O at 5ºC ______un

(k) 30 g NH4Cl in 200 g H2O at 10ºC ______un

(l) 40 g SO2 in 200 g H2O at 5ºC ______saturated

7. Tell how many MORE grams of each solute must be added to 100 g of water to form a saturated solution at that temperature.

8. Tell how many grams of each solute will crystallize/precipitate/settle. Assume all solutions are saturated and in 100 grams of H2O.

9. Rank the following solids in order from least to most soluble in 100 g H2O at 50ºC :

NH4Cl, NaNO3, KClO3, KNO3

KClO3, NH4Cl, KNO3, NaNO3

10. Rank the following gases in order from least to most soluble in 100 g H2O at 50ºC :

NH3, SO2, HCl

SO2, NH3, HCl

Skill #6: Expressing Concentration in Molarity or PPM - refer to your notes & RB p.108

11. Calculate the molarity of each of the following solutions:

(a) 2.5 mol of NaOH in 0.500 L of solution (b) 1.8L of solution containing 3.3 mol KNO3

M = 2.5/0.5 = 5.0 M M = 3.3/1.8 = 1.8 M

(c) 30. g of NaOH in 0.500 L of solution (d) 522 g of K2SO4 in 1.5 L of solution

mol = 30./40 = 0.75 mol mol = 522/174= 3 mol

M = 0.75/0.5 = 1.5 M M = 3/1.5 = 2 M

(e) 12 g of HCl in 250 mL of solution

mol = 12/36 = 0.33 mol

M = 0.33/0.25 = 1.3 M

12. Calculate the total moles of solute in each of the following solutions:

(a) 1.7 L of 0.35M NaOH (b) 50 mL of 3.3-molar KNO3

0.35 = X/1.7 = 0.595 mol 3.3 = X/0.050 = 0.165 mol

(c) 5.0 L of 1.25 M NaOH (d) 116 mL of 1.5 M K2SO4

1.25 = X/5.0 = 6.25 mol 1.5 = X/0.116 = 0.174 mol

13. Calculate the total grams of solute in each of the following solutions:

(a) 1.0 L of 0.5 M CaCl2 (b) 500 mL of 3.3-molar KNO3

0.5 = X/1.0 = 0.5 mol 3.3 = X/0.5 = 1.65 mol 0.5 = X/110 = 55 g CaCl2 1.65 = X/101= 167 g KNO3

(c) 0.25 L of 1.0 M NaOH (d) 42 mL of 1.7 M K2SO4

1.0 = X/0.25 = 0.25 mol 1.7 = X/0.042 = 0.0714 mol

0.25 = X/40= 10 g NaOH 0.0714 = X/174 = 12.4 g K2SO4

14. Calculate the concentration of chlorine in a swimming pool if there is 0.02 g of chlorine in 10,000 g of pool water.

ppm = (0.02/10,000) * 1,000,000 = 2 ppm

15. Exposure to lead has been linked to delays in physical and mental development and attention deficit disorders in children as well as kidney problems in adults. One source of this toxic heavy metal is drinking water in older homes whose plumbing contains lead. Water with a lead concentration of below 0.015ppm is considered safe to drink. A 100 g water sample taken from a home contains 1.2 x 10-6 grams of lead. Is this water considered safe to drink?

ppm = (1.2 x 10-6/100) *1 000 000 = 0.012 ppm

yes, it is safe to drink because it’s below 0.015 ppm

16. The health of fish depends on the amount of oxygen dissolved in the water. A dissolved oxygen (DO) concentration between 6 parts per million and 8 parts per million is best for fish health. A DO concentration greater than 1 part per million is necessary for fish survival. Fish health is also affected by water temperature and concentrations of dissolved ammonia, hydrogen sulfide, chloride compounds, and nitrate compounds.

A student’s fish tank contains fish, green plants, and 3800 grams of fish-tank water with 2.7 x 10-2 gram of dissolved oxygen.

a.)  State how an increase in the temperature of the fish-tank water affects the solubility of oxygen in the water. increasing the temperature Decreases the solubility of oxygen gas

b.)  Determine if the DO concentration in the fish tank is healthy for fish. Your response must include:

• a correct numerical setup to calculate the DO concentration in the water in parts per million

• the calculated result

• a statement using your calculated result that tells why the DO concentration in the water is or is not healthy for fish

ppm = (2.7 x 10-2/3800) * 1 000 000 = 7ppm

This is healthy for fish because it is greater than 1 ppm

c.)  Explain, in terms of molecular polarity, why oxygen gas has low solubility in water. Your response must include both oxygen and water.

Oxygen has low solubility in water because oxygen is nonpolar and water is polar.

d.)  Under what kind of conditions of temperature and pressure would oxygen gas be most soluble in water?

Low temperature and high pressure

e.)  An aqueous solution has a concentration of 7 ppm of oxygen dissolved in 1000. grams of water. Calculate the amount of oxygen in the solution in grams. Your response must include both a correct numerical setup and the calculated result.

7 = (X/1000) *1000000

X = 0.007 g O2

17. A safe level of fluoride ions is added to many public drinking water supplies. Fluoride ions have been found to help prevent tooth decay. Another common source of fluoride ions is toothpaste. One of the fluoride compounds used in toothpaste is tin(II) fluoride.

A town located downstream from a chemical plant was concerned about fluoride ions from the plant leaking into its drinking water. According to the Environmental Protection Agency, the fluoride ion concentration in drinking water cannot exceed 4 ppm. The town hired a chemist to analyze its water. The chemist determined that a 175-gram sample of the town’s water contains 0.000 250 gram of fluoride ions.

a.  Draw a Lewis electron-dot diagram for a fluoride ion.

b.  What is the chemical formula for tin(II) fluoride? SnF2

c.  How many parts per million of fluoride ions are present in the analyzed sample? 1.43

d.  Is the town’s drinking water safe to drink? Support your decision using information in the passage and your calculated fluoride level in question c. Safe: 1.43 ppm < 4 ppm

Skill # 7: Identifying Properties of Solutions - refer to your notes & RB p.110

18. Which solution has the highest boilingn point?

(1) 0.5 M NaCl

(2) 0.5 M CaCl2

(3) 1.0 M (NH4)3PO4

(4) 2.0 M CH3OH

19. Compared to pure water, an aqueous solution of calcium chloride has a

(1) higher boiling point and higher freezing point

(2) higher boiling point and lower freezing point

(3) lower boiling point and higher freezing point

(4) lower boiling point and lower freezing point

20. Which solution has the highest boiling point?

1.0 M KNO3 (3) 1.0 M Ca(NO3)2

(2) 2.0 M KNO3 (4) 2.0 M Ca(NO3)2

21. Which solution has the lowest freezing point?

(1)  10. g of KI dissolved in 100. g of water

(2)  30. g of KI dissolved in 100. g of water

(3)  20. g of KI dissolved in 200. g of water

(4)  40. g of KI dissolved in 200. g of water

22. As water is added to a 0.10 M NaCl aqueous solution, the conductivity of the resulting solution
(1) decreases because the concentration of ions decreases
(2) decreases, but the concentration of ions remains the same
(3) increases because the concentration of ions decreases
(4) increases, but the concentration of ions remains the same

23. Which aqueous solution of KI freezes at the lowest temperature?
(1) 1 mol of KI in 500. g of water (3) 1 mol of KI in 1000. g of water
(2) 2 mol of KI in 500. g of water (4) 2 mol of KI in 1000. g of water

24. Compared to a 2.0 M aqueous solution of NaCl at 1 atmosphere, a 3.0 M aqueous solution of NaCl at

1 atmosphere has a
(1) lower boiling point and a higher freezing point
(2) lower boiling point and a lower freezing point
(3) higher boiling point and a higher freezing point
(4) higher boiling point and a lower freezing point