C4 Chemical Changes Flashcards
Metal + acid –> ?
Salt + hydrogen
Metal hydroxide + acid –> ?
Salt + water
Metal oxide + acid –> ?
Salt + water
Metal carbonate + acid –> ?
Salt + water + carbon dioxide
What is a base?
A substance that can neutralise an acid, with a pH greater than 7
What is an alkali?
A base that dissolves in water to form a solution with a pH greater than 7
What is an acid?
A substance that forms aqueous solutions with a pH less than 7
What is the ionic equation for a neutralisation reaction?
OH- + H+ –> H2O
What is the reactivity series?
Potassium Sodium Calcium Magnesium Aluminium Carbon Zinc Iron Tin Lead Hydrogen Copper Silver Gold
What is an acronym for the reactivity series?
Please stop calling me a careless zebra. Instead, try learning how copper saves gold.
What is a displacement reaction?
When a more reactive metal displaces a less reactive metal in an aqueous solution of one of its salts.
What is an ion?
An atom with a charge
What is an ionic equation?
One that only shows atoms and ions that change in a reaction
Stomach acid pH
1
Vinegar and lemon juice pH
3
Acid rain pH
4
Rain pH
5
Pure water pH
7
Washing-up liquid pH
9
Pancreatic juice pH
10
Bleach pH
12
Drain cleaner pH
14
What is an indicator?
A dye that changes colour depending on whether it’s above or below a certain pH
What are wide range indicators? What are they useful for?
Indicators that contain a mixture of dyes, so they change colour gradually over a broad range of pH. They are useful when estimating pH.
How can you measure the pH of a solution?
With an indicator
With a pH probe attached to a pH meter
What is a pH probe? How accurate is it compared to an indicator?
An electronic device that measures the pH of a solution. They are more accurate than indicators because they output a number rather than a colour.
Acid + base –> ?
What is this reaction called?
Salt + water
Neutralisation
What is the pH of the products formed in a neutralisation reaction?
7 (neutral)
What do strong acids do in water?
They ionise completely - all the acid particles dissociate to release H+ ions.
What do weak acids do in water?
They don’t fully ionise - only a small proportion of acid particles dissociate to release H+ ions.
What do acids do in aqueous solutions?
They ionise
Why are strong acids more reactive than weak ones?
Reactions of acids involve the H+ ions reacting with other substances. If the concentration of H+ ions is higher, the reaction will happen faster.
What is the pH of an acid or alkali?
The concentration of H+ ions in the solution
How does the concentration of H+ ions change across the pH scale?
For every decrease of 1 on the pH scale, it multiplies by 10
Metal + water –> ?
Metal hydroxide + hydrogen
Which metals react with water? (4)
Potassium, sodium, lithium, calcium
Which metals do not react with water? (3)
Zinc, iron, copper
What is an ore?
A compound containing enough of a metal to make it worth the cost of extracting it
What is oxidation?
The gain of oxygen and the loss of electrons
What is reduction?
The loss of oxygen and the gain of electrons
What does OIL RIG stand for?
Oxidation Is Loss, Reduction Is Gain (of electrons)
Which metals can be extracted by reduction with carbon? (general case and 3 examples)
Those which are below carbon in the reactivity series.
Zinc, iron, copper
What does PANIC stand for?
Positive Anode, Negative Is Cathode
Which reactants are reduced and oxidised in a displacement reaction?
The metal ion is reduced, the metal atom is oxidised
Which ions are attracted to which electrodes in electrolysis?
The positive metal ions go to the negative cathode, the negative non-metal ions go to the positive anode.
