Starter quiz
- Match the following keywords to the correct description.
- neutral⇔a solution with a pH of 7 ✓
- acidic⇔a solution with a pH of 3 ✓
- alkaline⇔a solution with a pH of 14 ✓
- Which of the following statements about solvents is correct?
- A liquid in which a substance dissolves. ✓
- The mixture formed when a solid dissolves in a liquid.
- The ability of a substance to dissolve in a liquid.
- A liquid in which a substance will not dissolve.
-
- Which two of the following keywords can be used to describe a substance that can dissolve in a liquid?
- solute ✓
- soluble ✓
- solution
- solvent
-
- Some pH scales have a range from 0 to 14. Which of the following would describe a substance with a pH of 0?
- very strong acid ✓
- very strong alkali
- neutral
-
- The pH range most commonly used is from 1 to 14. What does the term 'range' mean?
- The largest value in an experiment.
- The smallest value in an experiment.
- The sum of the maximum and minimum values.
- The difference between the maximum and minimum values. ✓
-
- The lower the concentration of hydrogen ions in a solution, the ______ the pH of the solution.
- 'higher ' ✓
Exit quiz
- A pupil uses red cabbage to make an indicator. The solution produced is too pale to show a colour change. How could the method to make the indicator be improved?
- Use more water and less red cabbage.
- Use less water and more red cabbage. ✓
- Use less water and less red cabbage.
- Use green cabbage instead of red cabbage.
-
- Which of the following describe what a mortar and pestle are used for?
- crushing substances ✓
- mixing substances
- dissolving substances
- heating substances
-
- Match the following colours of red cabbage indicator to the correct type of the substance.
- pink or red⇔acidic solution ✓
- green⇔alkaline solution ✓
- purple⇔neutral solution ✓
- Which of the following statements explain why red cabbage and litmus are less effective than universal indicator at indicating the pH of a substance?
- Litmus does not clearly indicate when a solution is pH 7. ✓
- Red cabbage does not indicate when a solution is pH 7.
- Universal indicator turns a different colour for each pH from 1 to 14. ✓
- Red and blue litmus are more effective as indicators of pH than red cabbage.
-
- Different chemical indicators turn different colours at the same pH. Match the colour to the correct indicator if a solution has a pH of 7.
- red⇔red litmus ✓
- blue⇔blue litmus ✓
- green⇔universal indicator ✓
- purple⇔red cabbage indicator ✓
- A soluble substance dissolves in a solvent. If the solvent is water, what name is given to a soluble base?
- acid
- alkali ✓
- hydrogen
- neutral
-
Worksheet
Presentation
Video
Lesson Details
Key learning points
- Red cabbage solution is pink or red in an acid, purple in a neutral solution, and green in an alkali.
- Different chemical indicators have their advantages and disadvantages.
- Universal indicator will turn many different colours depending on pH.
Common misconception
Pupils often think that the red cabbage will change to the same colours as universal indicator solution.
Remind pupils that there are many different indicators used to show different pH.
Keywords
Universal indicator solution - a solution or paper that will turn different colours depending on pH of the solution.
Ph scale - is a scale from 1 to 14 used to measure the acidity or alkalinity of solutions. pH7 is for neutral solutions.
Pestle and mortar - are tools used to crush and grind substances. The pestle is a grinding club and the mortar a heavy bowl.
Chemical indicator - is a chemical that will change colour to indicate the presence of a substance, for example if a solution is an acid or alkali.
Solution - formed when a substance dissolves into a liquid.