Acids & Bases
This lesson covers:
- What the pH scale is
- How we can measure the pH of a solution
- The definitions of acids, alkalis, and bases
- Examples of neutralisation reactions
We measure the acidity or alkalinity of a solution using the scale.
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The pH scale ranges from:
0 to 14
0 to 7
-14 to 7
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What term can be used to describe solutions with a pH of 7?
Alkaline
Acidic
Neutral
Balanced
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What term can be used to describe solutions with a pH lower than 7?
Acidic
Neutral
Alkaline
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What term can be used to describe solutions with a pH greater than 7?
Acidic
Alkaline
Neutral
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What pH does stomach acid typically have?
About 7
About 12
About 2
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Select two ways by which the pH of a solution can be measured.
Reaction with water
Chemical indicator
Distillation
pH probe
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The pH of a solution can be measured using a type of chemical dye that changes colour, depending on the pH of the substance it's mixed with.
This chemical dye is usually referred to as:
pH dye
Acidity checker
Indicator solution
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indicator is made up of a several different indicator solutions. This means that it undergoes a smooth colour change over a wide range of pH values.
It becomes more in colour in acidic solutions, but more bluey-purple in solutions.
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What is the pH of pure water?
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A pH probe electronically measures the pH of a solution.
Select two reasons why using a probe may be more reliable than using an indicator.
A probe can be used in strongly acidic solutions
A probe produces a more accurate result
Determining the colour of an indicator is subjective
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A substance that forms an aqueous solution with a pH less than 7 is:
An ion
A base
An alkali
An acid
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Select the ion responsible for making an alkaline pH when dissolved in solution:
OH-
H+
H2O-
Na+
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Which of the following formulae represents nitric acid?
HNO3
NaOH
HCl
H2SO4
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Which of the following are acids?
(Select all that apply)
NaOH
HNO3
H2SO4
CaCO3
HCl
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Which of the following is represented by the formula CaCO3?
Calcium hydroxide
Calcium carbonate
Carbon dioxide
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