Chemistry - Topic 3 - Chemical Changes Flashcards
What ion do all acids produce in solution?
H+
What ion do all alkalis produce in solution?
OH-
What is the pH of a neutral solution?
7
What is the pH of an acid solution
1-6
What is the pH of an alkaline solution?
8-14
A 10cm3 solution of hydrochloric acid with a pH of 1 is made up to 1000cm3 with water. What is the new pH?
3 (every time it is diluted by 10 decreases the pH by 1)
Describe how a student could investigate how the pH of a solution of hydrochloric acid changes when small portions of calcium oxide are added.
- Use universal indicator paper or pH meter
- Add small amounts of calcium oxide and stir
- Measure the pH after each addition
What is a base?
A substance which reacts with an acid to form a salt and water
What is the difference between a dilute and concentrated acid?
A concentrated acid contains more H+ ions
What is the difference between a strong and weak acid?
A strong acid ionises fully
A weak acid ionises partially to release H+ ions
What is an alkali?
A base that dissolves in water to release OH- ions
State the general reaction between metals and acids
Metal + Acid –> Salt + Hydrogen
State the general reaction between metal oxides and acids
Metal oxide + acid -> Salt + Water
State the general reaction between metals hydroxides and acids
Metal hydroxide + acid –> Salt + water
State the general reaction between metal carbonates and acids
Metal carbonate + acid –> Salt + carbon dioxide + water