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Reacting metals with acids
metal + acid → salt + hydrogen
Reacting metal carbonates with acids
metal carbonate + acid → salt + water + carbon dioxide
reacting acids and bases
acid + metal oxide/hydroxide → salt and water (pH 7)
What is an acid
An acid is a substance that produces hydrogen ions, H+(aq), when dissolved in water. pH less than 7
what is an alkali
An alkali is a base that produces hydroxide ions, OH-(aq), when dissolved in water, pH more than 7
strong acids vs weak acids
strong - completely ionise in water (gives all H+ ions)
weak- partially ionise in water (gives only some H+ ions)
Universal indicator pH range
1- red
7 - green
14 - purple
Methyl orange pH range
acid - red
alkali - yellow
Phenolphtalein ph range
acid - clear
alkali - pink
litmus pH range
acid - red
alkali - blue
Advantages of indicator
cheap
easy to use
disadvantage of indicator
dyes solution
has to be compared with chart
not accurate
advantages of pH probes
very accurate
disadvantages of pH probes
expensive
-has to be calibrated
