Acids, Bases and Salts - Unit 1 Topic 8 Flashcards
What does charcoal do when making a dry, pure, soluble salt?
Removes the indicator
What do acids do when dissolved in water?
They are ionised
List 3 properties of acids
Taste sour
Corrosive
Low pH
What do soluble bases do when dissolved in water?
Produce hydroxides and ionise
List 3 properties of bases
Taste bitter
Feel slippery/soapy
Corrosives & high pH
Give 3 examples of everyday acids
Lemon juice
Stomach acid
Battery acid
Give 3 examples of everyday bases
Soap powder
Antacids
Baking soda
CHECK HAZARD SYMBOL KNOWLEDGE
Done
What is an indicator?
A dye that changes colour according to whether a substance is acidic or alkaline.
What does litmus paper turn in acidic and alkaline solution?
Blue = alkali Red = acid
What colour does phenolphthalein turn in acidic and alkaline solution?
Pink = alkali Colourless = acid
Universal indicator: Strong acids = Weak acids = Neutral = Weak alkalis = Strong alkalis =
Red Orange Green Blue Purple
What is a base?
A compound that will neutralise an acid
What are alkalis?
Soluble bases that produce hydroxide ions when dissolved in water
What is the strength of a substance?
Measure of the amount of ionisation. Measured by pH
What is the concentration of a substance?
Measure of the number of moles of acid/alkali molecules dissolved in 1dm3 of water. Measure by mol/dm3
What is the symbol for a hydroxide ion?
H+
Give 2 examples of real-life neutralisation
Indigestion (antacids against hydrochloric acid)
Lakes affected by acid rain add lime which saves the fish
What is neutralisation?
When an equal amount of H+ ions from an acid and OH- ions from an alkali react to form salt & water
What is a neutralisation reaction? (Exo or endo)
Exothermic
What is a salt?
When a metal takes the place of hydrogen in an acid
What salts do these acids form: Hydrochloric acid Sulfuric acid Nitric acid Ethanoic acid
Chloride
Sulfates
Nitrates
Ethanoates
What ions do these acids form: Hydrochloric acid Sulfuric acid Nitric acid Ethanoic acid
Cl-
SO4 2-
NO3 -
CH3COO-
Acid + metal ->
Acid + carbonate ->
Acid + alkali ->
Acid + base ->
Salt + hydrogen
Salt + water + carbon dioxide
Salt + water
Salt + water
What colour solution does magnesium + sulphuric acid give?
Colourless
What is the test for hydrogen?
Lighted splint. Squeaky pop.
What colour solution does copper oxide + sulphuric acid give?
Blue
What colour solution does copper carbonate + sulfuric acid give?
Blue
What is the general rule for oxides?
Metal oxides = basic
Non-metal oxides = acidic
What are 2 exceptions to the general oxides rule?
Water (hydrogen oxide)
Carbon monoxide
Both are neutral
What are amphoteric compounds?
React with both acids + alkalis
2 examples of amphoteric compounds
Aluminium hydroxide
Zinc hydroxide
Why can copper sulfate not be prepared by adding dilute sulfuric acid directly to copper?
Copper is unreactive so there will be no reaction
What colour is copper (II) oxide?
Black
In general, what colour are copper solutions?
Blue
In general, what colour are most Group I, Group II, aluminium and zinc compounds?
White
What colour of solutions do most Group I, Group II, aluminium & zinc compounds produce?
Colourless
3 ways to dry a salt
Dry between 2 pieces of paper
Dessicator
Low temperature oven
