Acids Flashcards
(24 cards)
What do alkalis have a greater ph than?
7
What do acids have a lower ph than?
7
What does a neutral solution have a ph of?
7
What colour is litmus in alkaline solutions?
Blue
What colour is litmus in an acidic solution?
Red
What colour is methyl orange in an alkaline solution?
Yellow
What colour is methyl orange in acidic solutions?
-red
What colour is phenolphthalein in alkaline solutions?
Pink
What colour are phenolphthalein in acidic solution?
Colourless
When are polyatomic ions formed?
When small groups of ions, held together by covalent bonds, lose or gain electrons
What do acids produce excess of when dissolved in water?
Hydrogen ions
What do alkalis produce excess of when they dissolve in water?
Excess hydroxide ions
What is a concentrated solution?
A solution that contains a lot of dissolved solute per unit volume
What is a dilute solution?
A solution that contains a small amount of solute per unit volume
How do you work out concentration?
Concentration =amount dissolved/volume of solution
What are bases?
Substances that neutralise acids to form a salt and water only
What are all metal oxides?
Bases
How are the salts produced in a neutralising reaction?
By replacing hydrogen ions with metal ions
What is a soluble base?
An alkali
Give some examples of soluble bases
- sodium hydroxide (NaOH)
- calcium hydroxide (Ca(OH)2
What happens to the temperature of the reaction mixture during a neutralisation reaction?
It increases
What is effervescence?
The formation of gas bubbles in a liquid due to a chemical reaction occurring
What do acids and metal carbonates form when reacted together?
Salt, water and carbon dioxide
What is a precipitation reaction?
A reaction in which soluble substances in solutions cause an insoluble precipitate to form.
