Acids & Alkalis Flashcards
What colour does litmus paper go for each solution?
Acid - red
Neutral - purple
Alkali - blue
What colour does phenolphthalein go for each solution?
Acid - colourless
Alkali - bright pink
What colour does methyl orange go for each solution?
Acid - red
Alkali - yellow
What is an acid?
A source of hydrogen ions (H+)
What is an alkali?
A soluble base and a source of hydroxide ions (OH-)
Acid + base -> ?
Salt + water
Acid + metal oxide ->?
Salt + water
What is the reaction between an acid and a base called?
Neutralisation
What is the pH of the products when an acid neutralises a base?
Neutral, pH 7
Acid + metal carbonate ->?
Salt + water + carbon dioxide
Acid + metal -> ?
Salt + hydrogen
Are all nitrates soluble or insoluble?
Soluble
Are common chlorides soluble or insoluble?
Soluble (except from silver chloride)
Are common sulfates soluble or insoluble?
Soluble (except barium sulfate and calcium sulfate)
Are common carbonates soluble or insoluble?
Insoluble (except Sodium, potassium and ammonium carbonates)
+ _
H + OH –> ?
H20
Hydrochloric acid + copper oxide –> ?
Copper chloride + water
Sulfuric acid + calcium carbonate –>?
Calcium sulfate + water + carbon dioxide
How do you make a soluble salt using acids and insoluble bases?
- You add the metal oxide/carbonate/Hydroxide to the acid and mix
- Filter out the excess base
- Heat the solution to remove some water
- Leave to crystallise
How do you make an insoluble salt?(precipitation reaction)
E.g. Making insoluble silver chloride
- Add 10 cm3 of Silver nitrate to 10cm3 of sodium chloride solution in a 100cm3 beaker
- Filter the mixture into a 250cm3 conical flask using filter paper and a funnel
- Wash the precipitate with cold water
- Dry the precipitate between filter papers
