Chemistry 12
Unit 4 - Acids, Bases and Salts
Chemistry 12
Open Book - Unit 4
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Common Acids and Bases
This worksheet is based on material on pages 109 - 114 of SW. (1 mark each)
1. What is the chemical name for muriatic acid? ____________________________________
2.
Which acid turns skin yellow on contact?_______________________________________
3.
Which acid is found in the human stomach? ____________________________________
5.
Which acid, in its concentrated form, will corrode copper? _________________________
6.
Concentrated sulphuric acid from the supplier is ______% H2SO4 and ______% H2O. The
molar concentration of this acid is _________M.
7.
Which acid turns skin white on contact?________________________________________
8.
List the four common uses of nitric acid. _______________________________________
________________________________________________________________________
9.
When ammonia (NH3) gas dissolves in water, it forms a compound called_____________
________________________________________________________________________
10.
What is the chemical name for caustic potash? __________________________________
11.
What is the chemical name for caustic soda or lye? _______________________________
12.
What two common bases are used in the production of soaps? ______________________
________________________________________________________________________
13.
Which acid is a non-electrolyte in its concentrated form? __________________________
14.
Write balanced formula equations for the reactions which happen when the following are
mixed: (2 marks)
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Mr. Wills
Chemistry 12
Unit 4 - Acids, Bases and Salts
a) Sodium hydroxide and phosphoric acid
_____________________________________________________________________
b) sulphuric acid and aluminum hydroxide
_____________________________________________________________________
Bronsted Acids and Equilibria
1.
Write the formula for a hydrated proton (1 mark)__________________
2.
Write the formula for a hydronium ion (1 mark) ___________________
3.
Give the Arrhenius definition of an acid (1 mark) ______________________________
______________________________________________________________________
4.
Give the Arrhenius definition of a base (1 mark) ______________________________
______________________________________________________________________
5.
Give the Bronsted definition of an acid (1 mark) _______________________________
______________________________________________________________________
6.
Give the Bronsted definition of a base (1 mark) _______________________________
______________________________________________________________________
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Mr. Wills
Chemistry 12
7.
Find the conjugate acids of each of the following (2 marks)
a)
HPO42- ____________________
b)
PO43- ____________________
8.
9.
Unit 4 - Acids, Bases and Salts
Find the conjugate bases of each of the following (2 marks)
a)
H2PO4- ____________________
b)
H3PO4 ____________________
Is the dihydrogen citrate ion amphiprotic? (1mark) __________________________
Explain your answer. (1 mark)
10.
What is the strongest acid that can exist in aqueous solution? (1 mark) ______________
11.
What is the strongest base that can exist in aqueous solution? (1 mark) ______________
12.
Classify each of the following as: a strong acid (SA), weak acid (WA), strong base (SB),
weak base (WB) or a spectator ion (S). (4 marks)
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a)
F-
__________
f) Cl-
______________
b)
HIO3
__________
g) NH3
______________
Mr. Wills
Chemistry 12
Unit 4 - Acids, Bases and Salts
What is the [OH-] in a solution made by adding 0.060 moles of calcium oxide to 500.0 mL water?
Be careful! (2 marks)
13.
14.
a) Write the balanced equation which describes the equilibrium present when
0.1 M HPO42- is mixed with 0.1 M H2C6H5O7-. (1 mark)
b) For this reaction, equilibrium tends to favour the (reactants/products) (1 mark)
c) For this reaction the value of Keq is (<1, >1 or about =1) (1 mark)
pH and pOH Calculations
1. Find the pH of the following solutions. Make sure you express your answer in the correct
number of significant digits. (4 marks)
1.
4
a) 0.0010 M HClO4 …..__________
b) 2.35 x 10-3 M KOH …___________
c) 4.678 x 10-5 M HNO3.._________
d) 12.0 M HCl ...............…__________
Find the [H3O+] in a solution with a pH = 3.216 (1 mark)
Mr. Wills
Chemistry 12
Unit 4 - Acids, Bases and Salts
2. Find the [OH-] in 0.150 M HClO4 (2 marks)
3. How much water should be added to 500.0 mL of a solution of HCl with a pH of 2.00 to bring the
pH to 2.50. Show all your work. (3 marks)
4.
What mass of NaOH should be added to 300.0 mL of water in order to prepare a solution with a
pH = 11.50. Show all your work. (4 marks)
Ka and Kb Calculations
1. Calculate the [H3O+] in a 0.45 M solution of hydrogen sulphide (H2S). (3 marks)
2. Calculate the pH in a 0.60 M solution of ammonium chloride (NH4Cl). (4 marks)
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Mr. Wills
Chemistry 12
Unit 4 - Acids, Bases and Salts
3. What concentration of the base CaO is needed to produce a solution with a pH = 14.00 (2 marks)
4. The weak base ethylamine (C2H5NH2) has a Kb of 6.4 x 10-4.
a) Write the equilibrium equation for ethylamine. (1 mark)
b) What [C2H5NH2] is required to produce an ethylamine solution with a pH = 12.102? (4 marks)
Hydrolysis
1. State whether each of the following substances are acidic, basic or neutral when mixed
with water. (3 marks)
a) RbNO3 ________
b) NH4Br ________
c) H2SO4 ________
2. Find Ka and Kb of each of the following amphiprotic anions and determine if they act as an
acid or a base in water solution. (6 marks)
a) HPO42-
Ka = __________ Kb = __________ A or B __________
b) HC6H5O72- Ka = __________ Kb = __________ A or B __________
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Mr. Wills
Chemistry 12
Unit 4 - Acids, Bases and Salts
3. Write the dissociation equations for each of the following. Determine the Ka for the
cation and the Kb for the anion and state whether the salt acts as an acid or a base
in water. (8 marks)
a) (NH4)2SO3 
Ka (cation) = __________ Kb (anion) ____________ = ____________
Salt is ____________________________________
b) Al(NO2)3 
Ka (cation) = __________ Kb (anion) ____________ = ____________
Salt is ____________________________________
Titrations
1. 13.45 mL of 0.200 M NaOH is required to titrate 25.0 mL of a solution which is known to have
HCl. Calculate the original [HCl]. Show all your steps. (3 marks)
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Mr. Wills
Chemistry 12
Unit 4 - Acids, Bases and Salts
Indicators
1. An indicator HInd is yellow in 0.1M NaOH and blue in 0.1M HCl. The pH range in which the
colour change occurs in this indicator is 3.6 - 5.2.
a) Write the equilibrium equation describing this indicator.(1)
b) What is the colour of HInd? _______ What is the colour of Ind-? _______ (1)
c) What is the pH at the transition point of this indicator? ____________ (1)
d) What is the value of pKa for this indicator? ______________ (1)
e) What is the Ka of this indicator? _____________________ (1)
f) At pH = 2.2, this indicator is the colour ______ and [HInd] (>,<,=) ___ [Ind-].(1)
2. A 0.10 M solution of a weak acid HX turns red in both chlorophenol red and in
neutral red indicator.
a)
Determine the approximate pH of this solution of HX. ____________ (1)
b)
Determine the Ka of the weak acid HX (Not the Ka (indicator)!)
(Hint: Use an ICE table!) (2)
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Mr. Wills
Chemistry 12
Unit 4 - Acids, Bases and Salts
3. An indicator “Gupta Green” (HGg) turns yellow when [H3O+] drops below
1.2 x 10-4 M and turns blue when [H3O+] rises above 1.8 x 10-3 M. (Notice 2 SD’s)
a)
Find the pH range over which the indicator changes colour.(2SD’s) (1)
pH Range _______- _______
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b)
Determine the pKa of the indicator “Gupta Green”. (1) _________________
c)
What colour would 0.00019 M HCl be in this indicator? (1) ______________
d)
What colour would 0.010 M NaOH be in this indicator? (1) _______________
Mr. Wills