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Units 3 - 4 --- Properties of acids and alkalis and Acid reactions (SC3)

Unit 3 --- Properties of Acids and Alkalis
 
In the sATs exam you will be expected to know properties of acids and alkalis.
 
Properties of Acids
 

Acids have a low pH --- a low pH is below pH7

Acids taste sour --- some weak acids are edible (e.g. vinegar) but have a sharp and sour taste.

Acids kill some cells --- acids can damage living cells like skin and bacteria
 
Acids produce Carbon Dioxide
 
Acids produce Hydrogen --- acids make hydrogen when they react with some metals
 
Properties of Alkalis
 
Alkalis have a high pH --- a high pH is above pH7
 
Alkalis often feel soapy --- they feel slimy when touched
 
Alkalis are soluble bases --- soluble bases dissolve in water to make an alkaline solution.
 
Alkalis can be corrosive --- they are often hard to wash off so they can burn your skin worse than an acid.
 
 
 
 

Unit 4 --- Acid reactions
 
Here are some general equations of "Acid reactions." You will only need to know the general equations, but it is helpful to apply examples to the equation to help you understand the acidic reaction more.
 
Equation One
 
General equation: ACID + BASE = SALT + WATER
Example equation: Hydrochloric Acid + Magnesium Oxide = Magnesium Oxide + Water
 
Equation Two
 
General equation: ACID + METAL = SALT + HYDROGEN
Example equation: Sulphuric Acid + Iron = Iron Sulphate + Hydrogen
 
Equation Three
 
General equation: ACID + METAL CARBONATE = SALT + WATER + CARBON DIOXIDE
Example equation: Nitric Acid + Calcium Carbonate = Calcium Nitrate + Water + Carbon Dioxide
 
If you want to be really clever (genius level) you can change the example equations to chemical symbols, however you do not need to know this for the sATs, so I left it out of this section.