Acids, Bases and Salts. Flashcards
What is an acid?
An acid is a proton donor (e.g. hydrochloric acid) substance which when dissolved in water, produces hydrogen ions (H+).
Name the four acid objectives.
Acids:
- Have a sharp, sour taste.
- Eat away skin and metal if they are concentrated.
- Turn blue litmus paper red.
- Corrosive.
Name 4 examples of weak acids in food.
Some weak acids are found in foods such as sour milk, vinegar, lemon juice, and yogurt.
Give two examples of strong acids.
Hydrochloric and sulphuric acid are strong acids.
What is a base and give 4 examples of bases?
A base is any substance that neutralizes an acid. Examples of bases are metal oxides, metal hydroxides, metal carbonates, and ammonia.
What is an alkali and give an example?
An alkali is a soluble base (e.g. sodium hydroxide and calcium hydroxide).
What are the five objectives of an bases?
Bases:
- Have an unpleasant, bitter taste.
- Feel soapy or slippery to the touch.
- Turn wet red litmus paper blue.
- Corrosive.
- Are used as cleaning products in the home.
What can strong bases do and give an example of a strong base?
Strong bases burn the skin if carelessly handled. An example of a strong base is sodium hydroxide.
What is a neutral substance and give 2 examples?
A substance that is neither acidic nor basic (e.g. distilled water and sodium chloride or NaCl.
What is Sodium chloride obtained from?
Sodium chloride, which is obtained by neutralization of hydrochloric acid and sodium hydroxide, is a neutral salt.
Name the two objectives of neutral substances.
Neutral substances:
- Have nither a bitter nor sour taste.
- Have no effect on either blue or red litmus paper.
What are indicators and give 2 examples of an indicator?
Indicators are used to identify acids and bases. Litmus paper and universal indicators are examples of indicators (Litmus is obtained from lichens).
What is a natural indicator and give 3 examples of them?
Natural indicators are obtained from plant materials. Some examples are red cabbage water, beetroot, and black tea.
What is the pH of a weak acid and what is the color?
High pH of 4, 5, or 6. The color is yellow.
What does a weak acid do and give 5 examples of weak acids?
A weak acid partially ionises/ dissociates in water to produce a few H+ (hydrogen) ions.
Examples of weak acids are organic acids, vinegar, citric acid, lactic acid, and tomatoes.
What is the pH of a strong acid and what is the color/
Low pH of 0, 1, or 2. The color is red.
What does a strong acid do and give 3 examples of strong acids?
A strong acid completely ionises in water to produce a lot of H+ (hydrogen) ions.
Examples of strong acids are hydrochloric acids, sulfuric acid, and nitric acid.
What effect do neutral substances have on litmus paper?
Has no effect on all litmus.
How do you form an alkaline solution and what do metal oxides and hydroxides do in water?
When an alkali dissolves, an alkaline solution is formed.
The oxide and hydroxide metals are alkalis and form alkaline solutions in water.
Fill in the missing answer:
Strong acids can be ______ or _____. To dilute a strong acid always add the ____ to the _____. Whenever it is concentrated or dilute, a strong acid will read pH _ - _.
Strong acids can be concentrated or dilute. To dilute a strong acid always add the acid to the water. Whenever it is concentrated or dilute, a strong acid will read pH 0 - 3.
Why should we never add the water to the acid?
Huge amounts of heat energy will be given off and this is dangerous.
`How do you dilute acid (methodically).
To dilute an acid, pour water into an empty container and then add a small amount of acid.
What is neutralization and what does it produce?
When acids and bases react together a chemical reaction called neutralization occurs. All neutralization reactions produce a salt and water.
What is a salt?
A salt is a compound that is formed when an acid reacts with a base.
