NGSS Regents Chemistry

1 Copyright © 2015 Tim Dolgos

NGSS Regents

Chemistry

PRACTICE PACKET Unit 9: Acids, Bases & Salts

*KEY* *KEY*

HC2H3O2(aq) + H2O(l) ↔ C2H3O2-(aq) + H3O

+(aq)


Acid/Base/Salt Characteristics: On the line on the left, write A if the statement is a property of an acidic solution. Write B if it is a property of a basic solution. Write X if it is a property of both acidic and basic solutions. BASE 1) Often feels smooth and slippery

ACID 2) Has a sour taste

ACID/BASE 3) Stings in open wounds

ACID 4) Typically reacts vigorously with metals

BASE 5) Has a bitter taste

ACID 6) Turns litmus paper from blue to red

ACID/BASE 7) Is an electrolyte

ACID/BASE 8) Often looks like pure water

BASE 9) Turns litmus paper from red to blue

BASE 10) Typically does not react with metals 11. Compare acids and bases in terms of H+ and OH- ion concentrations.

Acids have an excess of H+ in solution (more H+ than OH- ions in

solution), bases have an excess of OH- ions in solution (more OH- than

H+ ions in solution)

12. Explain what it means to be an electrolyte and why acids, bases and salts are electrolytes.

Electrolytes are substances that conduct electricity when dissolved in

water. Acids, bases, and salts have mobile ions (or mobile charges) when

dissolved in water which allows them to conduct electricity.








Multiple Choice Questions:

1) Basic solutions are those that contain an excess of a) H2 molecules b) H2O molecules c) H+ ions d) OH- ions

2) Acidic solutions are those that contain an excess of a) H2 molecules b) H2O molecules c) H+ ions d) OH- ions

3) A student accidentally spills an unknown chemical on her hand. She quickly washes it off, and notices that her skin feels slippery. She has an electrical conductivity tester at her lab station and tests the conductivity of the solution. It is a good conductor of electricity. The then places a strip of litmus paper in a sample of the liquid and it turns blue. She can conclude that the liquid is a a) strong base b) weak base c) strong acid d) weak acid

4) As 1 gram of sodium hydroxide dissolves in 100 grams of water, the conductivity of

the water will a) remain the same b) decrease c) increase

Recognizing/Naming Acids, Bases, & Salts: Question: What is the general formula for each of the following?

ACID BASE Question: What combinations of elements or ions qualify as a salt?

SALT

Substance Acid, Base, or Salt? Name 1. NaOH

BASE Sodium hydroxide

2. NH3 BASE

Ammonia

3. HCl ACID

Hydrochloric acid (hydrogen chloride)

4. NaCl SALT

Sodium chloride

metal & nonmetal metal & polyatomic ion

polyatomic ion & nonmetal 2 polyatomic ions

XOH

HA or HX


5. HF ACID

Hydrofluoric acid (hydrogen fluoride)

6. K2SO4 SALT

Potassium sulfate

7. AlPO4 SALT

Aluminum phosphate

8. Fe(OH)3 BASE

Iron (III) hydroxide

9. H2SO4 ACID

Sulfuric acid (dihydrogen sulfate)

10. H2CO3 ACID

Carbonic acid (dihydrogen carbonate)

11. LiC2H3O2 SALT

Lithium acetate

12. H3PO4 ACID

Phosphoric acid (trihydrogen phosphate)

13. Ca(NO3)2 SALT

Calcium nitrate

14. KOH BASE

Potassium hydroxide

15. MgCO3 SALT

Magnesium carbonate

16. NH4Br SALT/ACID

Ammonium bromide

17. HNO3 ACID

Nitric acid (hydrogen nitrate)

18. Ca(OH)2 BASE

Calcium hydroxide

19. MgCO3 SALT

Magnesium carbonate

20. NaNO3 SALT

Sodium nitrate

21. HCl ACID

Hydrochloric acid (hydrogen chloride)

22. KCl SALT

Potassium chloride

23. Ba(OH)2 BASE

Barium hydroxide

24. KOH BASE

Potassium hydroxide


25. H2S

ACID

Hydrosulfuric acid (hydrogen sulfide, dihydrogen monosulfide)

26. Al(NO2)3 SALT

Aluminum nitrite

27. CaCl2 SALT

Calcium chloride

28. Na2SO4 SALT

Sodium sulfate

29. Mg(OH)2 BASE

Magnesium hydroxide

30. NH4OH BASE

Ammonium hydroxide

31. NH4Cl SALT/ACID

Ammonium chloride

32. HBr

ACID

Hydrobromic acid (hydrogen bromide)

33. FeBr3 SALT

Iron (III) bromide

34. HC2H3O2 ACID

Acetic acid (hydrogen acetate)

35. CuCl2 SALT

Copper (II) chloride

36. HNO2 ACID

Nitrous acid (hydrogen nitrite)

37. HClO ACID

Hypochlorous acid (hydrogen hypochlorite)

38. HClO2 ACID

Chlorous acid (hydrogen chlorite)

39. HClO3 ACID

Chloric acid (hydrogen chlorate)

40. HClO4 ACID

Perchloric acid (hydrogen perchlorate)

41. H2SO3 ACID

Sulfurous acid (dihydrogen sulfite)

42. Al(OH)3 BASE

Aluminum hydroxide

43. LiOH BASE

Lithium hydroxide

44. HI ACID

Hydroiodic acid (hydrogen iodide)




Bronsted-Lowry Problems:

According to the Bronsted-Lowry theory, an acid is a proton (H+) donor and a base is a proton (H+) acceptor. In the forward reaction below, HCl acts as the acid, and OH- acts as the base.

Example: HCl + OH- Cl- + H2O

In the following equations, draw brackets between conjugate acid-base pairs and label each species as a Bronsted-Lowry acid or base, and answer the question.

1) According to the Bronsted-Lowry theory, what does H3O+ act as in the following reaction? ACID

CH3COO- + H3O+ CH3COOH + H2O

2) According to the Bronsted-Lowry theory, what does H2O act as in the following

reaction? BASE

HCl + H2O H3O+ + Cl-

3) According to the Bronsted-Lowry theory, what does NH3 act as in the following reaction? ACID

NH2- + H2O NH3 + OH-

4) According to the Bronsted-Lowry theory, what does H3O+ act as in the following

reaction? ACID

H3O+ + OH- H2O + H2O

5) According to the Bronsted-Lowry theory, what does CN- act as in the following reaction? BASE

CN- + H2O HCN + OH-

6) According to the Bronsted-Lowry theory, what does CH3COOH act as in the following

reaction? BASE

HClO4 + CH3COOH ClO4- + CH3COOH2

+


A CB

7) According to the Bronsted-Lowry theory, what does HCN act as in the following reaction? ACID

HCN + H2O H3O+ + CN-

8) According to the Bronsted-Lowry theory, what does NH4+ act as in the following

reaction? ACID

NH4+ + HSO4

- NH3 + H2SO4

9) According to the Bronsted-Lowry theory, what does Al(H2O)5(OH)+2 act as in the following reaction? BASE

HCl + Al(H2O)5(OH)+2 Cl- + Al(H2O)6

+3

Challenge Problems: 10) HCl + NaOH NaCl + H2O 11) KOH + HNO3 KNO3 + H2O 12) H2CO3 + 2H2O H3O+ + CO2 13) HCl + NH3 NH4

+ + Cl-

A CB

B CA

B CA

A CB

B CA

A CB

B CA


B CA A CB

A CB

A CB

B CA

B CA

B CA

14) H2O + NH3 NH4

+ + OH- 15) H2O + H2O H3O+ OH- 16) NH3 + NH3 NH4

+ + NH2-

17) H2SO4 + Ca(OH)2 CaSO4 + 2H2O 18) O3ClOH + H2O H3O+ + O3ClO- 19) H2O + HI H3O+ + I-

20) CH3COOH + H2O CH3COO - + H3O+ 21) NH4

+ + OH- NH3 + H2O 22) H2SO4 + OH- HSO4

- + H2O 23) HSO4

- + H2O SO4-2 + H3O+

B CA

A CB

A CB

A CB

B CA

B CA

B CA

B CA

B CA

A CB

A CB

A CB

A CB







A CB

B CA

A CB

B CA

A CB

B CA

A CB

B CA

More Bronsted-Lowry Acids and Bases:

Directions: For questions 1-4 please circle the correct answer.

1. What are the two acids in the following reaction?

H2O + HI ↔ H3O+ + I-

a. H2O and HI b. HI and I- c. H2O and I- d. HI and H3O+

2. What are the two acids in the following reaction?

CH3COOH + H2O ↔ CH3COO- + H3O+

a. CH3COOH and H3O+ b. CH3COOH and CH3COO- c. CH3COO- and H2O d. CH3COO- and H3O+

3. What are the bases in the following reaction?

H3PO4 + H2O ↔ H2PO4

- + H3O+

a. H3PO4 and H2O b. H2O and H2PO4-

c. H3PO4 and H2PO4- d. H2PO4

- and H3O+

4. What are the bases in the following reaction?

H2O + H2SO4 ↔ H3O+ + HSO4-

a. H2O and H2SO4 b. H2O and HSO4

-

c. H2O and H3O+ d. H3O+ and HSO4-

Directions: For questions 5-13 please circle the acids and underline the bases in the following reactions. 5. CH3COO- + H3O+ ↔ CH3COOH + H2O 6. H3O+ + OH- ↔ H2O + H2O 7. HCl + H2O ↔ H3O+ + Cl-


8. NH2- + H2O ↔ NH3 + OH-

9. NH4

+ + HSO4- ↔ NH3 + H2SO4

10. HCN + H2O ↔ H3O+ + CN-

11. HClO4 + CH3COOH ↔ ClO4

- + CH3COOH2+

12. SO4

2- + HNO3 ↔ HSO4- + NO3

-

13. CN- + H2O ↔ HCN + OH- 14. What is an amphoteric substance?

A substance that can act as either a base or an acid. _


The Power of pH: For each question, the two pH values are being compared. How many times more acidic or basic does the pH of the solution become?

1) pH 5 pH 3 102 or 100 x more acidic

2) pH 8 pH 4 104 or 10,000 x more acidic


4) pH 14 pH 7 107 or 10,000,000 x more acidic




8) pH 9 pH 3 106 or 1,000,000 x more acidic


10) pH 3 pH 6 103 or 1,000 x more basic

11) pH 1 pH 3 102 or 100 x more basic

12) pH 2 pH 7 105 or 100,000 x more basic

Circle the answer the best completes the following sentences: 13) The pH scale was developed to express ([H+]/[OH-]) as a number between 0

and 14.

14) A pH of 1 is a (strong/weak) (acid/base). 15) A pH of 8 is a (strong/weak) (acid/base).

16) In an acid, the [H+] </> [OH-].

17) In a base, the [H+] </> [OH-]. 18) A decrease from 5 to 4 on the pH scale represents a tenfold

(increase/decrease) in the concentration of ([H+] / [OH-]).

19) Strong acids and bases will dissociate (completely/slightly).





The pH Scale: A liquid may be an acid, base, or neutral. The degree of acidity or basicity can be measured by using the pH scale. The initials pH stand for the “power of Hydrogen” or for “Potential of Hydrogen.” The scale is divided into three areas: Acid (readings below 7), neutral (reading of 7), and basic (readings above 7). The strength of an acid or base depends on its ability to dissociate to form ions. When an acid or base completely ionizes or breaks down then we have a strong acid or base. For example, when 100 molecules of HCl dissolve in water, all 100 molecules dissociate to form H+ ions and Cl- ions:

HCl + H20 ↔ H+ (aq) + Cl- (aq)

A weak acid or base however only ionize or break down slightly. The fact that HCl dissociates so easily makes it a strong acid, and a good electrolyte. A weak acid on the other hand may only dissociate to form 1 H+ ion out of 100.

Each pH unit represents a tenfold difference of the H+ and OH- concentration. It is this mathematical feature that makes the pH scale so compact. For example a solution of pH 2 is not twice as acidic as a solution of pH 4, but a hundred times more acidic. The pH of 5 is ten times more acidic than a pH of 6. So when the pH of a solution changes slightly, it actually changes the concentrations of H+ and OH- substantially.

Measuring pH: To measure the pH of a solution we use pH indicators. A pH indicator is a paper strip or liquid solution that contains special chemicals or dyes that will change colors at different pH’s. An indicator is actually something called a Bronsted-Lowry conjugate acid-base pair in which the acid is a different color then the base. Common pH indicators can be found in Table M of your reference table.

Let’s take a look at table M. You will notice that it lists common acid-base indicators. For each indicator the name, an approximate pH range for color change and the color change is noted. Looking at bromthymol blue you will see that the color will change from yellow to blue at 6.0-7.6. Therefore, acids will maintain a yellow color, while bases will be blue. The diagram on the following page indicates the color change you will observe when using bromthymol blue at various pH’s.


0 6.0 7.6 14

Approximate pH range for color change: 6.0-7.6 Color of acid form: yellow Color of base form: blue

1. Given the pH scale below shade acids red, bases blue, and any neutral values green.

1 2 3 4 5 6 7 8 9 10 11 12 13 14

2. Will an acidic solution have more [H+] or [OH-] in solution? More [H+]

3. Will a basic solution have more [H+] or [OH-] in solution? More [OH-]

4. Will a neutral solution have more [H+] or [OH-] in solution? [H+] = [OH-]

5. A pH change from 5 to 6 will result in a change in [H+] by how much? 101 or 10 x less [H+]

6. A pH change from 9 to 7 will result in a change in [H+] by how much? 102 or 100 x more [H+]

7. What is a pH indicator? A substance that permanently changes color within a given pH range


pH & Indicators: Given the pH of the following common substances determine what color the indicator will turn when placed in each substance.

Substance pH Methyl

Orange Bromthymol

Blue Phenolphthalein Litmus Bromcresol

green Thymol

blue Stomach Acid

2 Red Yellow Colorless Red Yellow Yellow

Cola Drink

3 Red Yellow Colorless Red Yellow Yellow

Blood 7.5 Yellow

Green Colorless Purple Blue Yellow

Pure Water

7.0 Yellow


Oven Cleaner

14 Yellow Blue Pink Blue Blue Blue

Tomatoes 4 Orange

Yellow Colorless Red Green Yellow

Milk 6.5 Yellow


Detergent 10 Yellow

Blue Pink Blue Blue Blue

Coffee 5 Yellow

Yellow Colorless Purple Green Yellow

Household Cleaners

11 Yellow

Blue Pink Blue Blue Blue

For the following choose an appropriate indicator to note a transformation.

20) endpoint pH = 9 thymol blue, phth, *litmus 21) endpoint pH = 5 bromcresol green, *litmus, *methyl orange

22) endpoint pH = 3 methyl orange, bromcresol green


pH: pH is a scale that measures the hydronium ion (H+) concentration of a solution. A pH of less than 7 indicates an acidic solution. A solution with a pH of 7 is neutral. A solution with a pH of 7 to 14 is basic and contains a higher concentration of hydroxide ions than hydronium ions. Indicators are substances that change color in the presence of certain ions. Phenolphthalein is colorless in an acid and a neutral solution, but pink in a base. Litmus is red in an acid and blue in a base. This is outlined on Table M of the Reference Tables.

Solution PH range Methyl Orange

Thymol Blue

Litmus Brom- Cresol Green

Phenol- Phthalein

Brom-thymol

blue

Acid or Base?

Vinegar

1.3 Red Yellow Red Yellow Colorless Yellow Acid

Soap

8.4 Yellow

Green Blue Blue Light Pink

Blue Base

Cola

3.2 Orange Yellow Red Yellow Colorless Yellow Acid

Ammonia

12 Yellow

Blue Blue Blue Pink Blue Base

Rain

6.4 Yellow

Yellow Purple Blue Colorless Green Acid

Milk of Magnesia

8.1 Yellow

Green Purple Blue Light Pink

Blue Base

Milk

6.6 Yellow


Saliva

6.5 Yellow


Coffee

5.2 Yellow

Yellow Purple Green Colorless Yellow Acid

Gastric juices


Human blood

7.4 Yellow

Yellow Purple Blue Colorless Green Base

OJ


Kool-Aid

6.4 Yellow


Drain cleaner


Bleach

6.2 Yellow


Shampoo

6.3 Yellow



Neutralization Reactions: Remember that: Acid + Base Salt + Water Using the above general reaction, complete the following reactions with correct formulas. Then balance the entire double replacement reaction. Also name the salt that is produced in the space provided below the product side of the reaction. 1) ____ HNO3(aq) + ____ KOH(aq) ____ HOH + ____ KNO3

2) __2_ HCl(aq) + ____ Ca(OH)2(aq) __2_ HOH + ____ CaCl2

3) ____ H2SO4(aq) + __2_ NaOH(aq) __2_ HOH + ____ Na2SO4

4) ____ H3PO4(aq) + __3_ NaOH(aq) __3_ HOH + ____ Na3PO4

5) ____ NH4OH(aq) + ____ HI(aq) ____ HOH + ____ NH4I 6) ____ HClO(aq) + ____ NaOH(aq) ____ HOH + ____ NaClO 7) ____ Mg(OH)2 + __2_ CH3COOH __2_ HOH + ____ Mg(CH3COO)2

8) __3_ HNO3 + ____ Al(OH)3 __3_ HOH + ____ Al(NO3)3 9) ____ H3PO4 + __3_ LiOH __3_ HOH + ____ Li3PO4 10) ____ H2SO4 + ____ Mg(OH)2 __2_ HOH + ____ MgSO4

11) ____ NH4OH + ____ HCl ____ HOH + ____ NH4Cl


Writing Balanced Reactions:

Directions: In the following reactions an acid is reacting with a base in neutralization reactions. Write out the reaction and balance the equation.

1. Hydrochloric acid reacts with potassium

hydroxide

HCl + KOH → H2O + KCl

2. A sample of hydrochloric acid neutralizes calcium hydroxide

2HCl + Ca(OH)2 → 2H2O + CaCl2

3. H2SO4 reacts with NaOH

H2SO4 + 2NaOH → 2H2O + Na2SO4

4. Aluminum hydroxide is mixed with sulfuric acid

2Al(OH)3 + 3H2SO4 → 6H2O + Al2(SO4)3

5. Hydrobromic acid neutralizes a sample of

sodium hydroxide

HBr + NaOH → H2O + NaBr

6. A solution of HCl reacts with a solution of Ba(OH)2

2HCl + Ba(OH)2 → 2H2O + BaCl2

7. HCN neutralizes Ca(OH)2

2HCN + Ca(OH)2 → 2H2O + Ca(CN)2

8. HBr neutralizes calcium hydroxide

2HBr + Ca(OH)2 → 2H2O + CaBr2

9. **Ammonia reacts with perchloric acid

NH3+ HClO4 → NH4+ + ClO4

-

10. **KCN neutralizes HClO

KCN + HClO → HCN + KClO

CHALLENGE: A volume of 10 mL of 0.75 M sodium hydroxide neutralizes a 30 mL sample of hypochlorous acid. Write a balanced equation for the reaction and calculate the concentration of the acid.


ACID-BASE TITRATIONS: To determine the concentration of an acid (or base), we can react it with a base (or acid) of known concentration until it is completely neutralized. This point of exact neutralization, know as the endpoint or equivalence point, is noted by the change in color of the indicator. We use the following Titration formula from our Table T (Reference Tables):

MAVA = MBVB

Solve the following problems. SHOW ALL WORK! 1. A 25.0 mL sample of HCl was titrated to the endpoint with 15.0 mL of 2.0 M NaOH.

What is the molarity of the HCl?

1.2 M HCl 2. A 10.0 mL sample of H2SO4 was exactly neutralized by 13.5 mL of 1.0 M KOH. What is

the molarity of the H2SO4?

0.675 M H2SO4

3. How much 1.5 M NaOH is necessary to exactly neutralize 20.0 mL of 2.5 M H3PO4?

.100 L or 100. mL NaOH

4. How much of 0.5 M HNO3 is necessary to titrate 25.0 mL of 0.05 M Ca(OH)2 solution to the endpoint?

5.00 x 10-3 L or 5.00 mL of HNO3

5. What is the molarity of a NaOH solution if 15.0 mL is exactly neutralized by 7.5 mL of a 0.02 M HC2H3O2 solution?

.01 M NaOH


Titration Practice: A titration was set up and used to determine the unknown molar concentration of a solution of NaOH. A 1.2 M HCl solution was used as the titration standard. The following data were collected.

Trial 1 Trial 2 Trial 3 Trial 4 Volume of 1.2 M HCl

10.0 mL

10.0 mL

10.0 mL

10.0 mL

Initial Reading of NaOH

0.0 mL

12.2 mL

23.2 mL

35.2 mL

Final Reading of NaOH

12.2 mL

23.2 mL

35.2 mL

47.7 mL

Volume of NaOH used (mL)

12.2 mL

11.0 mL

12.0 mL

12.5 mL

Molarity of NaOH (M)

.984 M 1.09 M 1.00 M .960 M

1) Calculate the volume of NaOH used to neutralize the acid for each trial. Record in

data table above. Show one sample calculation below.

2) Using the MAVA = MBVB formula calculate the molarity of the base for each trial. Record in data table above. Show one sample calculation below.

3) Calculate the average molarity of the NaOH using your results from question 2.

Your answer must include the correct number of significant figures and the correct units.

1.01 M NaOH


6 mol/L

1.00 L

80 mL

0.2 mol/L

4) According to Reference Table M, what indicator would be most appropriate in determining the end point of this titration? Explain the reasoning behind your choice. Bromothymol Blue – end point has pH of 7.0, which falls in the range for b.blue (6.0-7.6)

5) Explain why it is better to use the average data from multiple trials rather than the data from a single trial to calculate the results of the titration.

6) If 3.00 liters of 2M HCl neutralizes 1.00 liter of NaOH, what is the molarity of the NaOH?

7) If 40mL of 2.50M HCl neutralizes 500mL of KOH, what is the molarity of the

KOH?

8) If 2.00 liters of 4.00M KOH neutralizes a HNO3 solution whose concentration is

8.00M, how many liters of HNO3 were neutralized? 9) How many mL of 1.00M HCl are needed to neutralize 400mL of 0.200M NaOH?

Any “bad data” will have less impact on the overall precision with a greater # of trials; greater # of trials helps to identify and overcome aberrations or experimental error.


25 mL

0.10 mol/L

2,500 mL

10) How many milliliters of 4.00 M NaOH are required to exactly neutralize 50.0 milliliters of a 2.00 M solution of HNO3?

11) ** If 21.0mL of 0.100M H2SO4 neutralizes 42.0mL of NaOH, what is the molarity of

the NaOH?

12) ** How many mL of 0.500M HNO3 are needed to neutralize 250mL of 2.50M

Ca(OH)2?


Titration Calculation Chart: MA VA MB VB

1

1.00M

25mL

4.00M

6.25 mL

2

2.00M

25mL

1 M

50mL

3

3.00M

50mL

1.5 M

100mL

4

6 M

1L

3.00M

2L

5

1.50M

1,000 mL

3.00M

500mL

6

6.00M

25 mL

2.00M

75mL

7

3 M

200mL

4.00M

150mL

8

5.00M

100mL

2.50M

200 mL

9

3.5M

400 mL

7.00M

200mL

10

2.50M

250mL

5.00M

125 mL

*Assume all acids and bases are MONOPROTIC


VB = 10 mL

VA = 20 L 2.0 moles

MA = 0.5 mol/L VB = 32 mL

5 x 10-2 moles MB = 2 mol/L

2 x 10-3 moles

pH = 7

MB = 1.0 mol/L

More Titration Calculations: 1) How many milliliters of 0.2M KOH are

needed to neutralize 20mL of 0.1M HCl?

2) How many moles of HCl are in 20mL of a

0.1M solution? 3) If 6mL of 1M HCl is exactly neutralized

by 3mL of KOH, what is the molarity of the KOH?

4) A 30 mL sample of HCl is completely

neutralized by 10mL of a 1.5M NaOH solution. What is the molarity of the HCl solution?

5) What is the total number of moles of

hydrogen ion that will be neutralized by 2.0 moles of hydroxide ion?

6) What is the molarity of a 250mL HCl solution that contains 0.25 moles of HCl?

7) Equal volumes of 0.5M HCl and 0.5M NaOH

are mixed. The total volume of the mixture is 2L. What is the pH of the solution?

8) How many moles of HCl can be neutralized

by 0.1 liters of a 0.5M NaOH? 9) How many milliliters of 5M NaOH are

needed to neutralize 40mL of 2M H2SO4? 10) How many liters of 0.2M HCl are needed to

neutralize 20 liters of 0.1M Ca(OH)2?


Neutralization Reactions & Titrations:

1) When 34.2 mL of a 1.02 M sodium hydroxide solution is added from a burette to 25.00 mL of a phosphoric acid solution that contains phenolphthalein, the solution changes from colorless to red.

A.) Write the balanced equation for the titration reaction.

B.) Calculate the molarity of the phosphoric acid.

2) 34.57 mL of an acetic acid solution are needed to neutralize 25.19 mL of 0.1025 M sodium hydroxide.


B.) Calculate the molarity of the acetic acid solution.

3) 0.300M nitric acid is titrated with 24 mL of 0.250M potassium hydroxide.


B.) Calculate the volume of the nitric acid.

.465 mol/L

3NaOH + H3PO4 → 3H2O + Na3PO4

HC2H3O2 + NaOH → H2O + Na C2H3O2

HNO3 + KOH → H2O + KNO3

20. mL or .020 L

.07469 mol/L


4) 0.250M sodium hydroxide is used to neutralize 116 mL of 0.0625M sulfuric acid.


B.) Calculate the volume of the sodium hydroxide.

2NaOH + H2SO4 → 2H2O + Na2SO4

58 mL or .O58 L


Show all work for the following word problems:

1) How many milliliters of 2.5 M HCl are required to exactly neutralize 1.5 L of 5.0 M NaOH? Use Table T.

2) A 2.0-mL sample of NaOH solution is exactly neutralized by 4.0 mL of 3.0 M HCl solution. What is the concentration of the NaOH solution?

3) A 30. mL volume of HCl is titrated with 23 mL of 0.20 M NaOH. What is the molarity of HCl in this solution?

4) A 26 mL volume of NH3 is titrated with 23 mL of 0.20 M HCl. What is the molarity of NH3 in this solution?

5) A 40. mL volume of H2SO4 is titrated with 38 mL of 0.24 M NaOH. What is the molarity of H2SO4 in this solution? (Be careful with this one!)

3.0 x 103 mL

6.0 M NaOH

0.15 M HCl

0.18 M NH3

0.11 M H2SO4 (diprotic acid)


Reactions with Acids and Bases:

1) Using Table J in your Reference Tables, list two metals that will react with H2 (or an

acid) Any metals above H2 on the table

2) Using Table J in your Reference Tables, list two metals that will NOT react with H2

(or an acid) Any metals below H2 on the table

3) What type of reaction (of the four we have learned) is involved when an acid reacts

with a metal? Single replacement

4) Write the general formula (using ABC etc.) for this type of reaction

X + HA → H2 + XA

5) Predict the products of the following reaction:

Mg + 2HNO3 H2(g) + Mg(NO3)2

5) Will copper react with an acid? NO Explain your answer in terms of activity

Copper is less active than H2; copper doesn’t give up its e- as easily as H2

6) Predict the products of the following neutralization reaction:

RbOH + HBr RbBr + H2O

7) Set up a reaction below that would occur between HNO3 and LiOH. Predict the products using your general reaction for neutralization reactions.

HNO3 + LiOH → H2O + LiNO3

8) Predict the products of the following reaction. Remember to create your formulas using the criss cross rule! BALANCE the reaction also.

H2SO4 + Ca(OH)2 2H2O + CaSO4

Name salt that was produced Calcium Sulfate

9) According to your reference tables, which metal would react spontaneously with hydrochloric acid?

a. Gold b. Silver c. Copper d. Zinc


WORKSHEET ON THE REACTIVITY SERIES 1) Use table J and your knowledge of chemistry to answer the following questions in

complete sentences.

a) Why does gold occur native (uncombined) whereas zinc does not?

Gold is a much less active metal than zinc.

b) Why was silver used to make coins in the past?

Silver is a rare metal (very valuable) and an unreactive metal (very safe).

c) Why is copper used to make electrical cables and wires?

Copper is an excellent electrical conductor.

d) Why do we know so little about the lifestyles of the people of the Iron Age?

Iron is a fairly active/reactive metal and corrodes/rusts easily.

2) Rank the following metals in order of reactivity (most reactive = 1, least reactive = 4)

3 zinc 1 sodium 2 magnesium 4 copper

a) Which metals will react when added to dilute hydrochloric acid? Describe the reaction.

Sodium, magnesium, and zinc will react with HCl by forcing their electrons onto

hydrogen and forming H2 gas.

b) Which of the four metals would be suitable for making saucepans? Explain why the others are not. Copper because it is not an active metal. The other metals would react with

water or anything acidic in the food being cooked.

c) Which of the four metals forms a protective coating when it oxidizes?

Zinc

3) Describe what you would see if you dropped a piece of magnesium ribbon into some copper sulphate solution in a test tube. Write a word equation for the reaction.

You would see fizzing and bubbling, the color would fade from (blue to clear), and

solid copper would precipitate out of solution while the magnesium ribbon dissolved.

Solid magnesium metal loses electrons to copper ions.


4) Complete the following word equations.

a) zinc + lead nitrate solution → lead + zinc nitrate solution

b) iron + zinc sulphate solution → no rxn

c) lead + copper nitrate solution → copper + lead nitrate solution

d) magnesium + zinc chloride solution → zinc + magnesium chloride solution

e) copper + sodium chloride solution → no rxn

f) zinc + iron sulphate solution → iron + zinc sulphate solution

g) gold + silver nitrate solution → no rxn

h) magnesium + calcium nitrate solution → no rxn

5) Three metals X, Y and Z have the following reactions:-

Y will displace X from a solution of its salt.

Z will displace both X and Y from solutions of their salts.

Place the three metals in order of reactivity, starting with the least reactive.

X, Y, Z

6) Here is a list of metals in order of decreasing reactivity. Q and R are mystery metals.

K > Q > Ca > Mg > Al > Zn > R > Fe > Cu

a) Will Q react with cold water? Yes

b) Will R react with cold water? No

c) Will R react with dilute hydrochloric acid? Yes

d) Will R displace copper from copper sulphate solution? Yes

e) Write word equations for any reactions in parts a) to d)

a) Q + water → QOH(aq) + H2(g) or Q + water → Q(OH)2(aq) + H2(g)

c) R + HCl → RCl(aq) + H2(g)

d) R + CuSO4(aq) → Cu(s) + R2SO4 or R + CuSO4(aq) → Cu(s) + RSO4


a) Yes: iron + copper (II) sulphate solution → copper + iron (II) sulphate solution

or

iron + copper (II) sulphate solution → copper + iron (III) sulphate solution

b) No rxn

c) Yes: copper + silver nitrate solution → silver + copper nitrate solution

d) Yes: zinc + lead nitrate solution → lead + zinc nitrate solution


a) Yes: iron + copper (II) oxide → copper + iron (II) oxide

or

iron + copper (II) oxide → copper + iron (III) oxide

b) Yes: aluminum + iron oxide → iron + aluminum oxide

c) No rxn

d) Yes: magnesium + zinc oxide → zinc + magnesium oxide

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NGSS Regents Chemistry