Acids, Bases and Salts Flashcards
Colour of litmus in acid and alkali
Red in acid, blue in alkali
Colour of phenolphthalein in acid and alkali
Colourless in acid, pink in alkali
Colour of Methyl orange in acid and alkali
Red in acid, yellow in alkali
Acid+Metal =
Salt+Hydrogen
Magnesium reacts rapidly with dilute acids to form solutions of magnesium salts. What colour is the solution?
Colourless.
Zinc reacts readily but not as much as magnesium because it is less reactive, what colour are zinc salts?
Colourless.
Iron salts are…
Colourless.
Acid+base…
Salt+Water
Acid+metal carbonate…
Salt+Water+Carbon Dioxide
Acid+Metal Hydgrogencarbonate…
Salt+Water+Carbon Dioxide
Define an acid
Acids are substances which dissolve in water to form the H+ (aq) ion.
Define a base
Bases are substances which react with acids i.e combine with H+ ions. Bases include metal oxides, metal carbonates and metal hydroxides.
Define an alkali
Akalis are bases which dissolve in water to form the OH- (aq) ion. An alkali is a soluble base, all alkalis are bases but not all bases are alkalis.
Define neutralisation
is a reaction of an acid with a base and it always results in the formation of a salt.
When hydrogen burns what happens
Hydrogen oxide which is just H20 or water.
Test to see if water is present
Cobalt chloride paper is used, it is blue when no water is present and turns pink when exposed to moisture.
Test to show that water is pure
To show that a sample of water is pure, its boiling point can be measured. Pure water boils at 100 degrees, any impurities might change the boiling point.
What compounds are soluble?
- All common nitrates
- All common sulfates
- All common chlorides
- All potassium, sodium and ammonium compounds are soluble
- Sodium hydroxide, potassium hydroxide and ammonium hydroxide
- Sodium carbonate, potassium carbonate and ammonium carbonate
Which compounds are insoluble?
- All common carbonates
- All common hydroxides
- Calcium sulfate, barium sulfate and lead sulfate
- Silver chloride and lead chloride
What solubility of salt do you prepare in precipitation?
- Insoluble
How do you form an inoluble salt from a precipitation?
- Two solutons are mixed, each containing one of the two ions required to form the salt.
- On mixing these two ions combine and form the insoluble salt, which preciptates out of the solution, other ions are spectator ions.
- Preciptate is filtered off; washed, by pouring a little distilled water over the precipitate in the filter paper; then left to dry.
How do you make barium sulfate?
- Insoluble salt so precipitation method
- Two solutions needed, one barium compoun and one sulfate compound.
- Barium nitrate and sodium sulfate
- Two solutions are mixed, and the barium sulfate precipates out.
- Filtered washed and dried.
What solubility of salt do yu prepare in titration?
- Soluble
What two types of solutions do you sue in a titration?
- Acid and soluble base (alkali)
What general salts are prepared using titration?
- Sodium, potassium and ammonium salts
How do you prepare a soluble solt from titration?
- A known volume (usually 25cm3) of acid is measured in conical flask, using pipette.
- Few drops of indicator, such as phenolphathalein are added.
- Alkali placed in a burette and slowly added to conical flask.
- Whe indicator changes colour, with phenolphathalein, purple then the volume of alkali that has been added is recorded.
- Process repeated, to obtain a an accurate, average value.
- Once this exact volume is known, the process is repeated once more but without the indicator.
- Then warm the solution in a evaporating basin.
- Boil off half of the water to concentrate the soluton, then let the remainder cool and evaporate slowly to form large crystals.
How do you make sodium chloride?
- It is soluble, so made by titration
- To make chlorine salte, hydrochloric acid must be used.
- To make sodium chloride we use sodium hydroxide.
What four methods could be used to determine the end point of a titration reaction?
- Use an indicator.
- Use a pH meter.
- Measure the conductivity of the solution.
- Measure the amount of heat released into the solution.
What solubilty of slat is prepared in a reaction of an acid with an insoluble base?
- Used to prepare soluble salt from an insoluble base
How do you do a reaction of an acid and an insolubl base?
- Appropriate acid is placed in a beaker and warmed.
- Small portion of appropratie metal oxide or carbonate is added to warm acid and stirred.
- The oxide or carbonate reactions with the acid, forming a sosluble salt and appears to dissolve in the acid.
- More of the oxide or carbonte is added, a little at a time, with stirring.
- When acid has all been neutralsied the oxide or carbonate has nothing to react with and being insoluble sinks to the bottom.
- His can be filtered off, leaing pure salt solution.
- To obtain solid salt from solution, it is wamed gently in an evaporating basin and about half the water is boiled off to concentrate the osltuon.
- The remained is allowed to cool and to evaporate slowly forming large crystals
How do you make copper(II) sulfate?
- To make sulfate salt, sulfric acid must be used
- Copper (II) sulfate is soluble, so precipitation cannot be used.
- Copper (II) hydroxide is insoluble, so titration cannot be used.
- So reaction of an acid with an insoluble base is used.
