Name _____________________________
PHYSICAL SCIENCE TWO 2012 Answers
ACIDS & BASES QUIZ
Section A: Multiple Choice Questions
1.
A
B
C
D
When a metal reacts with hydrochloric acid, the products are:
A salt and oxygen gas.
A salt and hydrogen gas.
A salt and water.
Water and carbon dioxide.
2.
A
B
C
D
Which one of the following statements about bases is true? Bases:
Unlike dangerous acids, are generally quite safe.
Are just stronger types of acids.
Are found in citrus fruits.
Are used in many cleaning products.
3.
A
B
C
D
Adding liquid X to water decreases its pH. This shows that the liquid X is:
An acid.
A base.
Neutral.
Water.
4.
Which list shows the four substances in order from the strongest acid to the strongest
base?
Sulphuric acid, acetic acid, pure water, cloudy ammonia, sodium hydroxide
Acetic acid, sulphuric acid, pure water, sodium hydroxide, cloudy ammonia
Pure water, sulphuric acid, cloudy ammonia, acetic acid, sodium hydroxide
Sodium hydroxide, cloudy ammonia, pure water, acetic acid, sulphuric acid
A
B
C
D
5.
A
B
C
D
When an acid and base react together, which substances would you always expect to be
produced?
A salt and oxygen gas
A salt and hydrogen gas
A salt and water
Water, a salt and carbon dioxide
6.
A
B
C
D
A reaction in which an acid reacts completely with a base to produce water is called:
An acidic reaction
A decomposition reaction
A neutralisation reaction
A precipitation reaction.
7.
A
B
C
D
Antacid tablets contain:
A special medicinal acid extracted from ants
Alternative acids for dissolving food that are milder than stomach acid
Substances designed to speed up the reaction of stomach acid in food
A chemical that dissolves in the stomach to release a base.
Part B: Short Answer
1.
Balance each of the following equations AND state the type of equation: precipitation,
ionic, neutralisation or combustion (3 x 2 = 6).
a.
C3H8 (g) + O2 (g) → CO2 (g) + H2O (g)
C3H8 (g) + 5O2 (g) → 3CO2 (g) + 4H2O (g) Combustion Reaction
b.
Ba2+ (aq) + PO43– (aq) → Ba3(PO4)2 (s)
3Ba2+ (aq) + 2PO43– (aq) → Ba3(PO4)2 (s) Precipitation/Ionic Reaction
c.
Ba(OH)2 (aq) + H2SO4 (aq) → BaSO4 (aq) + H2O (l)
Ba(OH)2 (aq) + H2SO4 (aq) → BaSO4 (aq) + 2H2O (l)
2.
Neutralisation Reaction
Write a fully, balanced chemical equation to describe a chemical reaction in which
solid sodium hydrogen carbonate reacts with a dilute solution of hydrochloric acid to
form carbon dioxide gas and a solution of sodium chloride and water (2).
NaHCO3(s) + HCl(aq) → NaCl(aq) + CO2(g) + H2O(l)
3.
Calculate the pH of a 0.010 M HNO3 solution (1).
pH = -log10 [H+] = -log10 0.01 = 2
4.
Calculate the hydrogen ion (H+) concentrations of orange juice with a pH of 3.5 (1)
[H+] = 10-pH = 10-3.5 = 3.16 x 10-4 M or 0.000316 M
5.
Blood has a pH of 7.4. A urine sample has a pH of 5.4. How many times more acidic is
the urine than blood (1)?
Change in pH in 2 indicates that urine is 102 = 100 times more acid than blood.
6.
You are provided with 20 mL of a solution of pH 4. Explain how you could use this
solution to prepare a solution of pH 5 (2 marks)
A change in pH from 4 to 5 indicates a 10 fold decrease in concentration.
Therefore you would need to dilute your solution from 20 mL to 200 mL by adding
180 mL of water.
2
DATA SECTION
pH = -log10 [H3O+]
POSITIVE VALENCY
[H3O+] = 10-pH
NEGATIVE VALENCY
aluminium
Al3+
bromide
Br-
ammonium
NH4+
carbonate
CO32-
barium
Ba2+
chloride
Cl-
calcium
Ca2+
chromate
CrO42-
chromium
Cr3+
dichromate
Cr2O72-
copper (I)
Cu+
fluoride
F-
copper (II)
Cu2+
hydroxide
OH-
hydrogen
H+
hydride
H-
iron (II)
Fe2+
iodide
I-
iron (III)
Fe3+
nitrate
NO3-
lead (II)
Pb2+
nitrite
NO2-
lead (IV)
Pb4+
nitride
N3-
magnesium
Mg2+
oxide
O2-
mercury
Hg2+
permanganate
MnO4-
potassium
K+
phosphate
PO43-
tin (II)
Sn2+
phosphide
P3-
tin (IV)
Sn4+
silicide
Si4-
silver
Ag+
sulphate
SO42-
sodium
Na+
sulphide
S2-
zinc
Zn2+
sulphite
SO32-
3