Indicators, Acids and Alkalis Flashcards
Define an indicator and give an example.
2 marks
An indicator is something that can tell whether a substance is acidic or alkaline. An example is universal indicator.
Describe how to make a red cabbage indicator.
4 marks
- Stir some cut leaves of red cabbage in a beaker of boiling water to obtain a red solution.
- Filter the solution to remove all solids.
- Add to acid or alkali.
It will turn pink/red if it is an acid, and it will turn green/yellow if it is an alkali.
Define the pH scale. Where on the scale would you find a weak or strong acid or alkali?
3 marks
The pH scale is a way of measuring how concentrated an acid or alkali is. It runs from 0 - 14, with 0 being strong acid, 7 being neutral and 14 being strong alkali.
What is a neutralisation reaction?
1 mark
When acids and alkalis mix, they cancel each other out. This is called neutralisation.
All metal oxides are 1)………. . Some 2)………. dissolve in water to form hydroxides ( 3)………. ), for example calcium oxide forms the 4)………. calcium hydroxide.
4 marks
- Bases
- Bases
- Alkalis
- Alkali
When a base neutralises an acid, you use the first name of the 1)………. and it becomes the first name of the 2)………. .
Copper oxide + Sulfuric acid ====> Copper sulfate + Water
2 marks
- Base
- Salt
Carbonates can make 1)………. . All carbonates make 2)………. when added to 3)………. .
4)………. + Carbonate ====> 5)………. + Water + 6)……….
6 marks
- Salts
- CO₂
- Acids
- Acid
- Salt
- CO₂
What is the test for CO₂?
2 marks
- Bubble it through limewater
- Limewater turns cloudy/milky
Metal + Acid ====> 1)………. + 2)……….
2 marks
- Metal salt
- Hydrogen
Define acid rain and how it is caused by the burning of fossil fuels. List some effects.
3 marks
Acid rain is rain with a pH of below 7. It is formed when carbon dioxide from the burning of fossil fuels gets dissolved into the water. It can erode landscapes and damage wildlife.
