Acids and Alkalis Flashcards
Name three common household acids:
Vinegar, lemon juice, car battery.
Name three common household alkalis:
Soap, drain cleaner, baking powder.
State a hazard of strong acids and alkalis
They are corrosive
What is an indicator?
A chemical that changes colour in an acid and alkali.
Give 3 examples of indicators
Red cabbage indicator; litmus paper; universal indicator
What does the pH scale tell us about acids and alkalis?
How strong an acid or alkali is.
Name the chemical used to identify the pH of a substance:
Universal indicator
What is the colour of a universal indicator in a neutral substance?
Green
What is the pH of a neutral substance?
pH 7
Give an example of a neutral substance:
Water, blood, salt
What is the colour of the universal indicator in a strong acid?
Red
What is the pH of a strong acid?
1-3
Give an example of a strong acid:
Car battery acid; hydrochloric acid
What is the pH of a weak acid?
4-6
Give an example of a weak acid:
Vinegar; tomato juice; citric acid in lemon juice; coffee
State the colour of strong alkalis on the pH scale?
Purple
What is the pH of a strong alkali?
11-14
Give an example of a strong alkali:
Bleach, drain cleaner
What is the pH of a weak alkali?
8-10
Give an example of a weak alkali:
Soap, baking powder
What is a neutralisation reaction?
When an acid and an alkali react together.
What are the products of a neutralisation reaction?
Salt and water
Write the general word equation for a neutralisation reaction:
Acid + alkali 🡪 salt + water
What type of salt is produced when an alkali reacts with:
a) Hydrochloric acid
b) Nitric acid
c) Sulphuric acid
a) Metal chloride
b) Metal nitrate
c) Metal sulphate
Describe 3 examples of everyday neutralisation reactions:
- Brushing your teeth using toothpaste to neutralise mouth after eating acidic foods.
- Farmers use lime to neutralise acidic soil.
- Indigestion tablets containing alkalis are used to neutralise stomach acid.
Sodium Hydroxide + Hydrochloric acid
Sodium Chloride + Water
Potassium Hydroxide + Nitric acid
Potassium Nitrate + Water
Lithium Hydroxide + Sulphuric acid
Lithium Sulphate + Water
A sample of pure salt can be made by reacting copper oxide with sulphuric acid. Complete the word equation:
Copper Oxide + Sulphuric acid
Copper Sulphate + Water
Explain why it is important to stir the copper oxide with the sulphuric acid as it is added when making a sample of dry crystals:
Allows the copper oxide to react with the sulphuric acid.
Name the technique shown in the diagram below and explain why it is important when making a sample of dry crystals:
Filtration: allows any unreacted copper oxide to be removed.
Name the technique shown in the diagram below and explain why it is important when making a sample of dry crystals:
Evaporation: allows the water to be evaporated off, leaving behind the salt.
