Starter quiz
- What happens to the pH when a base is added to an acidic solution?
- the pH decreases
- the pH increases ✓
- the pH stays the same
- the pH becomes negative
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- What is the purpose of Universal Indicator paper?
- to measure the temperature of a solution
- to detect whether a substance contains metal ions
- to determine the pH of a solution by showing a range of colours ✓
- to identify whether a gas is being produced
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- What does plotting pH changes on a graph help determine?
- the rate of temperature change
- the point at which neutralisation occurs ✓
- the volume of liquid in a beaker
- the exact amount of gas released
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- Why is accurate data collection important?
- to ensure safety in the laboratory
- to save time during an experiment
- to ensure reliable and reproducible results ✓
- to make sure equipment is clean
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- What is observed when pH changes around the neutralisation point?
- the temperature of the solution increases
- the pH remains constant
- a gas is produced
- the indicator changes colour suddenly ✓
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- What does a colour change on the Universal Indicator paper indicate?
- the temperature of the solution has increased
- a chemical reaction has finished
- the pH of the solution has changed ✓
- the solution has become saturated
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Exit quiz
- Match each of the following key terms to the correct definitions.
- pH⇔a measure of hydrogen ion concentration ✓
- neutralisation⇔a reaction between an acid and a base ✓
- base⇔increases pH when added to an acid ✓
- quantitative⇔data represented as numerical values ✓
- hydrogen ion (H⁺)⇔responsible for acidity in a solution ✓
- What happens to the pH of a basic solution when an acid is added?
- the pH decreases ✓
- the pH increases
- the pH stays the same
- the pH becomes negative
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- What is neutralisation?
- A reaction that lowers the pH of a solution.
- A reaction between an acid and a base to form salt and water. ✓
- The process of dissolving a solid in water.
- The reaction between an acid and a metal.
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- How does pH change near the neutralisation point?
- the pH remains constant
- the pH decreases slowly
- the pH increases or decreases rapidly ✓
- the pH slowly increases then levels off
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- What can be determined by plotting pH on a graph during neutralisation?
- the rate of temperature change
- the amount of acid required to neutralise the base ✓
- the concentration of the base
- the speed of the reaction
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- Which of the following is an example of a base?
- hydrochloric acid
- sodium hydroxide ✓
- sulfuric acid
- carbon dioxide
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Worksheet
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Presentation
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Video
Lesson Details
Key learning points
- When powdered hydroxide/oxide (base) is added to an acidic solution there is an increase in pH.
- pH changes quickly around the neutralisation point.
- Indicators, such as Universal Indicator paper, can be used to collect quantitative data on pH.
- pH can be plotted on a graph to find the quantity of base required to neutralise an acid.
Common misconception
All added calcium hydroxide dissolves completely, and the pH readings are accurate without consistent mixing.
Calcium hydroxide has low solubility in water, so not all of it dissolves readily. Consistent mixing ensures uniform pH readings. Without proper mixing, pH readings can be inaccurate, leading to incorrect conclusions about the neutralisation point.
Keywords
Ph - A measure of the hydrogen ion (H⁺) concentration in a solution.
Neutralisation - A chemical reaction between an acid and base to produce a neutral solution of a metal salt and water.
Base - A substance that neutralises an acid to form a salt and water.
Quantitative - Refers to a measurement of quantity. A numerical value.
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