C3.3 - types of chemical reactions Flashcards
what is neutralisation?
the reaction between acids and a base/alkali to form a salt and water only
does the pH of the solution during neutralisation change?
yes, depending on the concentration of acid/alkali
what salt is produced when copper oxide powder neutralises sulfuric acid?
copper sulfate
what are the products produced during the neutralisation of:
sodium hydroxide + hydrochloric acid ->
sodium chloride + water
what is the equation during the reaction of an acid and a metal carbonate?
acid + carbonate -> salt + water + carbon dioxide
what are the products of the following reaction:
hydrochloric acid + calcium carbonate ->
calcium chloride + water + carbon dioxide
metal carbonate
what is the word equation during the reaction of a metal oxide and an acid?
Acid + oxide → salt + water
what are the products of the following reaction:
hydrochloric acid + magnesium oxide ->
magnesium chloride + water.
what is the word equation of the reaction between a metal hydroxide and acid?
hydroxide + acid -> salt + water
what are the products of the following reaction:
hydrochloric acid + sodium hydroxide →
sodium chloride + water
what happens during neutralisation in solution?
- acidic solutions contain H+ ions (hydrogen)
- alkaline solutions contain OH- ions (hydroxide)
- they both react together and produce water
what is a redox reaction?
a reaction where reduction and oxidation happens at the same time
what is reduction in terms of oxygen?
loss of oxygen
what is oxidation in terms of oxygen?
gain of oxygen
looking at the following equation what is the oxidising and reducing agent and why?
aluminium + iron oxide -> aluminium oxide + iron
iron oxide is the oxidising agent as is oxidises aluminium to aluminium oxide
aluminium is the reducing agent as it reduces iron oxide to iron
what is the mnemonic for remembering oxidation/reduction/ electrons etc.?
OIL RIG
- > oxidation is loss
- > reduction is gain
do redox reactions always have to involve oxygen?
no, it can just be a loss/gain of electrons
what is an acid? (in terms of what it releases when dissolved in water)
a substance which releases hydrogen ions when dissolved in water
what makes a solution acidic?
hydrogen ions
what is a base?
a substance that can neutralise acids
what does an alkali release when dissolved in water?
OH- ions
what makes a solution alkaline?
hydroxide ions
what does pH < 7 mean?
acidic
what does pH = 7 mean?
neutral
what does pH > 7 mean?
alkaline
what do you use to show the pH of a solution?
- universal indicator
- pH meter
what are carbonates?
ionic compounds that contain the carbonate ion (CO3 2-)
what do carbonates form when react with acids?
salt + water + carbon dioxide
what is produced when a metal reacts with an acid?
salt + hydrogen
what salt is produced when magnesium and hydrochloric acid reacts together?
magnesium chloride
why does a piece of magnesium ribbon appear to have dissolved if placed into acid?
- hydrogen is released as bubbles
- salt magnesium chloride is formed
what is a dilute acid?
an acid which contains a low ratio of acid to volume of solution
what is a concentrated acid?
an acid which contains a high ratio of acid to volume of solution
what is a weak acid?
acids that partially ionise (only a small fraction of their molecules release H+ ions)
what is a strong acid?
acids that fully ionise (all molecules release H+ ions)
what does a pH titration curve show?
the effect on pH by changing the hydrogen ion concentration during a neutralisation reaction
What needs to be done before measuring pH with a pH meter?
Calibration to get accurate results :
Wash the pH probe with water, then put it into a calibration buffer.
Adjust the reading to match the pH of the buffer solution.
When measuring pH with pH meter what needs to be done?
Wash probe with water, put into solution, record reading
Wash probe with water between each measurement to ensure not contaminated with previous sample
How pH changes with hydrogen ion concentration?
As concentration of H+ ions increase by a factor of 10, the pH of a solution decreases by 1
For a given volume of solution, the greater the amount of _ it contains, the greater it’s concentration.
Solute
Difference between acid strength and concentration
Acid strength - idea that acid strength is a measure of the degree of ionisation of the acid
Concentration - idea of number of moles (of acid) in 1 dm3
