solutions q and a from text

(1)

CHAPTER 5

Writing Dissociation Equations

BLM 5.1.2

OVERHEAD

Soluble Compounds in Solution

NaCl(s)

Na

+

_{(aq) + Cl}

–

_(aq)

Ba(OH)

2

(s)

Ba

2+

(aq) + 2OH

–

(aq)

C

3

H

7

OH(ℓ)

C

3

H

7

OH(aq)

C

12

H

22

O

11

(s)

C

12

H

22

O

11

(aq)

HCl(g)

H+(aq) + Cl

–

_(aq)

Insoluble Compounds in Solution

AgCl(s)

Ca(OH)

2

(s)

Ca(OH)

2

(s)

C

25

H

52

(s)

C

25

H

52

(s)

Solubility of Some Common Ionic Compounds in Water at 25

º

C

Solubility

_NH

Group 1

4+

H

+

ClO

–

NO

3–

ClO

4–

CH

3

COO

–

Cl

–

Br

–

I

–

SO

4

2–

_S

2–

_OH

–

_PO

43–

Very

soluble

(solubility≥

0.1 mol/L)

all

most

_{Grp 1}

Grp 2

NH

4+

Grp 1

NH

4+

Sr

2+

Ba

2+

Tl

+

Grp 1

NH

4+

Slightly

soluble

(solubility

< 0.1

mol/L)

none

Ag

+

Hg

+

Ag

+

Pb

2+

Hg

+

Cu

+

Tl

+

Ca

2+

Sr

2+

Ba

2+

Ra

2+

Pb

2+

Ag

+

most

CLASS:

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H2O

Ionic

Compounds

H2O

Covalent

Compounds

H2O

Acids

H2O

Ionic

Compounds

H2O

Covalent

(2)

CHAPTER 5

Solubility and Writing

Dissociation Equations Quiz

BLM 5.1.3

ASSESSMENT

1. Identify which of the following compounds are soluble in water.

(a)

NaCl(s)

(b)

AgCl(s)

(c)

BaSO

4

(s)

(d)

C

12

H

22

O

11

(s) (table sugar)

(e)

NH

4

OH(s)

(f)

Ca(NO

3

)

2

(s)

(g)

C

25

H

52

(s) (candle wax)

(h)

Mg(OH)

2

(s)

(3)

2. Identify which of the following classes of compounds are electrolytes:

(a)

soluble ionic compounds

(b)

insoluble ionic compounds

(c)

soluble molecular compounds

(d)

insoluble molecular compounds

(e)

molecular compounds that ionize in water (acids)

3. Write dissociation equations for the following compounds in water.

(a)

LiF(s)

(b)

Ca(CH

3

COO)

2

(s)

(c) CH3OH(ℓ)

(d)

HgBr(s)

(e)

PbSO

4

(s)

(f)

HBr(g) (acid)

(g) CCl4(ℓ)

(h)

O

2

(g)

(i)

(NH

4

)

3

PO

4

(s)

CHAPTER 5

Solubility and Writing

Dissociation Equations Quiz

(continued)

BLM 5.1.3

ASSESSMENT

4. Draw a flow chart to aid in writing dissociation equations for soluble and insoluble ionic and

molecular compounds.

(4)

CHAPTER 5

Solubility and Writing

Dissociation Equations Quiz

Answer Key

BLM 5.1.3A

ANSWER KEY

1. Identify which of the following compounds are soluble in water.

(a)

NaCl(s)

Soluble

(b)

AgCl(s)

(c)

BaSO

4

(s)

(d)

C

12

H

22

O

11

(s) (table sugar)

Soluble

(e)

NH

4

OH(s)

Soluble

(f)

Ca(NO

3

)

2

(s)

Soluble

(g)

C

25

H

52

(s) (candle wax)

(h)

Mg(OH)

2

(s)

(5)

2. Identify which of the following classes of compounds are electrolytes:

(a)

soluble ionic compounds

Electrolytes

(b)

insoluble ionic compounds

Although some will dissolve enough to light a conductivity

apparatus, they are not electrolytes.

(c)

soluble molecular compounds

(d)

insoluble molecular compounds

(e)

molecular compounds that ionize in water (acids)

Electrolytes

3. (a)

LiF(s)

Li

+

_{(aq) + F}

–

_(aq)

(b)

Ca(CH

3

COO)

2

(s)

Ca

2+

(aq) + 2CH

3

COO

–

(aq)

(c) CH3OH(ℓ) CH3OH(aq)

(d)

HgBr(s)

HgBr(s) (solubility less than 0.1 mol/L)

(e)

PbSO

4

(s)

PbSO

4

(s) (solubility less than 0.1 mol/L)

(f)

HBr(g) (acid)

H

+

_{(aq) + Br}

–

_(aq)

(g) CCl4(ℓ) CCl4(ℓ) (solubility less than 0.1 mol/L)

(h)

O

2

(g)

O

2

(g) (solubility less than 0.1 mol/L)

(i)

(NH

4

)

3

PO

4

(s)

3NH

4+

(aq) + PO

43-

(aq)

CHAPTER 5

Solubility and Writing

Dissociation Equations Quiz

Answer Key

(continued)

BLM 5.1.3A

ANSWER KEY

4.

H2O

(6)

CLASS:

CHAPTER 5

Calculations Involving Percent

by Mass, Parts per Million, and

Parts per Billion

BLM 5.3.2

ASSESSMENT

1. What is the concentration of a solution in percent m/m given that 83.62 g of a salt have been added to water to make 400.0 g of solution?

Is the compound molecular or ionic?

Molecular Decide whether the compound is polar or

non-polar.

Polar Replace the original state notation of the compound with (aq).

Non-polar Retain the original state

notation.

Ionic

Use a solubility table to determine if it is soluble

or insoluble.

Soluble Break into ions, add (aq)

notation, balance the equation.

Insoluble Keep as a whole compound. Keep (s)

(7)

2. In a lab, 6.48 g of table salt are added to 90.00 mL of water. What is the concentration of this solution expressed in percent by mass?

3. What mass of solute is dissolved in 1.200 kg of a 5.20% (m/m) solution?

CHAPTER 5

Calculations Involving Percent by

Mass, Parts per Million, and Parts

per Billion

(continued)

(8)

4. On the label of a bottle of water it is stated that there are 0.48 mg Na+_{per 250 mL of water. What is the}

concentration expressed in ppm?

5. Raising the concentration of carbon dioxide in a greenhouse to approximately 10 000 ppm is effective in eliminating pests such as mites. What is the mass of carbon dioxide that would be present in 1 kg of air?

(9)

7. Determine the mass of sodium fluoride that could be isolated from a 170 g tube of 1500 ppm fluoride toothpaste.

CHAPTER 5

Calculations Involving Percent by

Mass, Parts per Million, and Parts

per Billion Answer Key

BLM 5.3.2A

ANSWER KEY

1.

2.

3.

(10)

CHAPTER 5

Calculations Involving Percent by

Mass, Parts per Million, and Parts

per Billion Answer Key

(continued)

BLM 5.3.2A

ANSWER KEY

5.

6.

7.

NAME: CLASS:

CHAPTER 5

Calculating Molar

Concentration

(11)

c = concentration (in mol/L)

n = amount of solute (in mol)

V = volume of solution (in L)

1. Calculate the concentration of the following solutions in mol/L given:

(a) 0.43 mol of magnesium sulfate, MgSO4(s), dissolved in enough water to make 1.25 L of solution.

(12)

(c) 422 mg of ammonium nitrate, NH4NO3(s), dissolved in enough water to make 500 mL of solution.

CHAPTER 5

Calculating Molar

Concentration

(continued)

BLM 5.3.3

ASSESSMENT

(d) 32.47 g of copper(II) sulfate pentahydrate, CuSO45H2O(s), dissolved in enough water to make 2.7 L of

(13)

(e) 5.2 g of glucose, C6H12O6(s), dissolved in enough water to make 500 mL of solution.

(f) 8.235 g of barium hydroxide, Ba(OH)2(s), dissolved in enough water to make 0.7500 L of solution.

(g) 3 g of chromium(III) nitrate, Cr(NO3)3(s), dissolved in enough water to make 450 mL of solution.

CHAPTER 5

Calculating Molar

Concentration Answer Key

BLM 5.3.3A

ANSWER KEY

(14)

(b)

(c)

(d)

CHAPTER 5

Calculating Molar Concentration

Answer Key

(cont’d)

BLM 5.3.3A

ANSWER KEY

(15)

(f)

(g)

CHAPTER 5

Molar Concentration of Ions in

Solution

(16)

K

2

SO

4

(s)

2 K

+

(aq) + SO

42–

(aq)

The concentration of K

+

_{(aq) ions is double the concentration of K}

2

SO

4

(s) and SO

42–

(aq).

NAME: CLASS:

CHAPTER 5

Calculating the Molar Concentration

of Ions in Solution

BLM 5.3.5

ASSESSMENT

H

2

(17)

c = concentration (in mol/L)

n = amount of solute (in mol)

V = volume of solution (in L)

To determine the concentration of ions, first write a dissociation equation and then multiply by the molar ratio of ions in the compound.

1. Determine the concentration of the hydroxide ions present in a 2.45 mol/L solution of strontium hydroxide, Sr(OH)2(aq).

2. Calculate the molar concentration of potassium ions if 1.37 g of potassium carbonate, K2CO3(s) is dissolved

(18)

3. Determine the molar concentration of the anion (negative ion), if 1.2 g of magnesium chloride, MgCl2(s) is

dissolved in enough water to make 2.0 L of solution.

CHAPTER 5

Calculating the Molar

Concentration of Ions in

Solution

(continued)

BLM 5.3.5

ASSESSMENT

4. What is the molar concentration of ammonium ions if 5.2 g of ammonium thiosulfate, (NH4)2S2O3(s), is

dissolved in enough water to make 4.7 L of solution?

(19)

6. If the molar concentration of strontium ions in a solution of strontium nitrate, Sr(NO3)2(aq) is

0.35 mol/L, determine the molar concentration of nitrate ions in that solution.

CHAPTER 5

Calculating the Molar

Concentration of Ions in

Solution Answer Key

BLM 5.3.5A

ANSWER KEY

1.

(20)

CHAPTER 5

Calculating the Molar

Concentration of Ions in Solution

Answer Key

(continued)

BLM 5.3.5A

ANSWER KEY

(21)

4.

CHAPTER 5

Calculating the Molar

Concentration of Ions in Solution

Answer Key

(continued)

BLM 5.3.5A

ANSWER KEY

(22)

6.

NAME: CLASS:

CHAPTER 5

Calculating Mass and Volume

from Concentration

BLM 5.3.6

ASSESSMENT

(23)

2. Determine the mass of solid lead(II) nitrate, Pb(NO3)2(s), required to prepare 125 mL of a

0.40 mol/L solution of lead(II) nitrate.

3. What mass of anhydrous sodium sulfate, Na2SO4(s), is required to make 1.00 L of a 1.00 mol/L solution?

CHAPTER 5

Calculating Mass and Volume from

Concentration

(continued)

(24)

4. What volume of a 0.033 mol/L solution may be made from 4.97g of solid ammonium phosphate, (NH4)3PO4(s)?

5. How many litres of a 2.50 mol/L solution may be made from 1.45 g of magnesium sulfate?

(25)

CHAPTER 5

Calculating Mass and Volume from

Concentration Answer Key

BLM 5.3.6A

ANSWER KEY

1.

2.

3.

(26)

CHAPTER 5

Calculating Mass and Volume from

Concentration Answer Key

(continued)

BLM 5.3.6A

ANSWER KEY

5.

6.

NAME: CLASS:

CHAPTER 5

Mixed Concentration Problems

BLM 5.3.7

ASSESSMENT

(27)

2. How many litres of a 0.200 mol/L solution of copper(II) nitrate solution, Cu(NO3)2(aq), may be prepared

from 2.2 g of solute?

3. Calculate the concentration in ppm of a solution made by dissolving 4.75 g of sodium fluoride in 3.75 L of solution (the density of water is 1 g/mL).

(28)

CHAPTER 5

Mixed Concentration Problems

(continued)

BLM 5.3.7

ASSESSMENT

5. What mass of potassium permanganate, KMnO4(s), would have to be dissolved to make 375 mL of a 0.50

mol/L solution?

(29)

7. What is the concentration in ppb if 2.5 10–5_{g of chlorine is dissolved in a bathtub containing 135 L of}

water?

8. Determine the molar concentration of a solution made by dissolving 0.0235 g of magnesium sulfate, MgSO4(s), in enough water to make 225 mL of solution.

CHAPTER 5

Mixed Concentration Problems

(continued)

BLM 5.3.7

ASSESSMENT

(30)

10. What mass of aluminum chloride, AlCl3(s), would have to be dissolved to make 225 mL of a 0.100 mol/L

solution?

(31)

12. What mass of sodium carbonate, Na2CO3(s), would be required to produce 100 mL of a 0.250 mol/L

solution?

CHAPTER 5

Mixed Concentration Problems

(continued)

BLM 5.3.7

ASSESSMENT

13. Determine the volume of a 0.47 mol/L solution that could be made using 1.35 kg of ammonium fluoride, NH4F(s).

(32)

CHAPTER 5

Mixed Concentration Problems

Answer Key

BLM 5.3.7A

ANSWER KEY

1.

2.

3.

(33)

CHAPTER 5

Mixed Concentration Problems

Answer Key

(cont’d)

BLM 5.3.7A

ANSWER KEY

5.

6.

7.

(34)

CHAPTER 5

Mixed Concentration Problems

Answer Key

(cont’d)

BLM 5.3.7A

ANSWER KEY

9.

10.

(35)

CHAPTER 5

Mixed Concentration Problems

Answer Key

(cont’d)

BLM 5.3.7A

ANSWER KEY

12.

13.

(36)

NAME: CLASS:

CHAPTER 5

Dilution Calculations

BLM 5.4.1

ASSESSMENT

moles of solute (before dilution) = moles of solute (after dilution)

c1V1 = c2V2

c1 = concentration before dilution

V1 = volume before dilution

c2 = concentration after dilution

V2 = volume after dilution

1. Determine the concentration of a solution made by diluting 25.0 mL of a 3.00 mol/L solution of sodium hydroxide, NaOH(aq), to a volume of 500.0 mL.

2. What volume of concentrated 18 mol/L sulfuric acid, H2SO4(aq), is needed to prepare 250 mL of a 6.0

(37)

3. To what volume should 15.0 mL of a 5.0 mol/L of aqueous potassium chloride, KCl(aq), be diluted in order to prepare a 0.25 mol/L solution?

4. A solution is made by diluting 200 mL of an unknown stock solution to 750 mL. The concentration of the diluted solution is determined to be 0.0275 mol/L. What is the concentration of the original stock solution?

5. To how much water should 100 mL of 18 mol/L sulfuric acid, H2SO4(aq), be added to prepare a 1.5 mol/L