Acid/Base
Neutralisation
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Question 1
a) Which picture displays the chemical formula for hydrochloric acid?
2.
1.
H
CI
H
3.
H
O CI
H
C
H
Answer:
Write the chemical formula for hydrochloric acid.
b) The following shows the structure of sulfuric acid.
Write the chemical formula for sodium hydroxide.
Give one safety precaution when working with a
sodium hydroxide solution in the laboratory.
c) Write a balanced equation for the picture below.
O
Balanced equation:
C
O
O
O
Sodium hydroxide is used in the laboratory.
O
H
S
Write the chemical formula for sulfuric acid.
C + O
H
O
O
H
d) HNO3 is the chemical formula for nitric acid.
How many atoms are there in a molecule of nitric acid?
e) The Chemistry Café cook has a loaf which had 33 slices of bread and a package of
cheese that has 15 slices of cheese.
He is making sandwiches that have 2 slices bread and 1 slice of cheese
How many sandwiches can he make?
Using B as the symbol for a slice of bread and C for a slice cheese, write a balanced
equation to represent the making of one sandwich.
+
=
The customers are not happy with his sandwiches. He decides to put 3 slices of cheese
into each sandwich. Write a balanced equation for the making of this sandwich.
+
=
If he also put in a slice of ham (symbol Hm), show what the equation would now be.
f) The following is the balanced equation for the preparation of carbon dioxide.
2HCl + CaCO3
CaCl2 + CO2 + H2 O
What does the 2 in front of the HCl tell you?
What does the small 2 after O in CO2 tell you?
Question 2
Red cabbage is an indicator used to identify if substances are acid or base.
What colour do you think the red cabbage indicator would be in concentrated
sulfuric acid?
Give a reason for your answer.
What colour would red cabbage indicator be in vinegar?
Give a reason for your answer.
What colour would red cabbage indicator be in a solution of calcium hydroxide?
Give a reason for your answer.
A scientist needs 10 cm3 of solution X to neutralise 20 cm3 of solution Y in an
investigation.
How many cm3 of solution X will the scientist need to neutralise 30 cm3 of solution Y?
Explain what is meant by the word neutralise in chemistry.
Why do farmers add lime (calcium hydroxide) to acidic soils?
A student uses red cabbage indicator to identify what type of solution is in each beaker.
A
B
The liquid in Beaker A turns red cabbage indicator a yellow colour.
What does this tell you about the liquid in A?
When the liquid in beaker B was added to the liquid in beaker A, the solution in A
turned light blue.
What does this tell you about the liquid in beaker B?
Heartburn is caused when your stomach is upset by the production of too much acid.
People may take bread soda (sodium bicarbonate) to relieve the heartburn.
What is the scientific purpose of the bread soda?
What do you think the pH of the bread soda is?
Question 3
When an acid reacts with a base, a salt and water are produced. A student needs to
prepare a salt in the laboratory using the chemicals below and other scientific apparatus
not shown.
Write the word equation for the reaction between these two substances to produce
the salt.
Write the chemical equation for the reaction between these two substances to produce
the salt.
The student did the experiment using a data logger and a pH meter.
20 cm3 of hydrochloric acid was put in a beaker. The base sodium
hydroxide was added using a burette and the pH was recorded at 2 cm3
intervals.
pH
volume of base added (cm 3)
What was the pH of the acid at the start of the experiment?
What happened to the pH of the solution as the base was added?
Why do you think there is a sudden jump in pH between adding 18 cm3 and 20 cm3 of base?
What volume of base would be required to get a solution with a pH of 7?
At pH 7, what is the solution in the beaker made up of?
How much of this base would be needed to neutralise 100 cm3 of this acid?
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