Acids and Alkalis Flashcards
What is this hazard symbol for?
Two test tubes dripping onto something
Corrisive
Can dissolve other sustances on contact
Causes burns on skin
What is this hazard symbol for?
Exclamation mark
Harmful Irritant
May cause skin or eye irritation
What is this hazard symbol for?
Skull and crossbones
Toxic
Can cause death if inhaled or ingested
Why do we have hazard symbols?
To give a warning about any dangers of chemicals
Why are hazard symbols used instead or words?
Univerisally recognisable
Eye catching
Easy to understand
What is the PH of a neutral substance
PH 7
What is an acid
A substance with a PH less than 7
What is an alkali?
A base that is soluble in water. It has a PH more than 7.
Give some examples of acids found at home
Orange juice
Lemon juice
Vinegar
Coffee
Give some examples of alkalis found at home
Toothpaste
Bleach
Oven cleaner
Soap
Give some examples of acids found in the laboratory
Hydrochloric acid
Sulphuric acid
Nitric acid
Give some examples of alkalis found in the laboratory
Sodium hydroxide
Potassium hydroxide
Ammonia
What is the difference between alkalis and bases?
A base is something that reacts with an acid to form water and a salt.
An alkali is any base that is soluble in water.
What is an indicator used for?
To identify an unknown solution as an acid or alkali.
What is an indicator?
A dye that changes colour in the presence of an acid or alkali
Names some indicators?
Litmus solution
Universal indicator
Red cabbage/beetroot indicator
What colour does an universal indicator change to for acids
Red
What colour does an universal indicator change to for alkalis
Blue
What colour does an universal indicator change to for a neutral solution
Green
What happens if you mix an alkaline solution with an equal amount of an acidic solution?
They react to produce a neutral solution
What is the reaction called when an acid and alkali produce a neutral solution?
Neutralisation
What happens to the PH when an alkali is added to an acid.
The PH is raised.
What is produced in neutralisation reactions?
Salt and water.
What do all acids contain?
Hydrogen
What is Hydrochloric acid?
Hydrogen chloride
What is Sulfuric acid?
Hydrogen sulfate
What is Nitric acid?
Hydrogen nitrate
Describe a neutralisation equation
Reactants on the left, products on the right.
What is a base?
Any subtance which neutralises an acid. It has a pH of over 7.
Are all bases soluble in water?
No a lot are insoluble in water
What is a base that is soluble in water known as?
Alkali
What do chemical names for alkalis tend to end in?
Hydroxide
What is the chemical name for water?
Hydrogen hydroxide
What is the general equation for neutralisation?
Acid + Alkali (or base) —> Salt + water
What is the shape of a neutralisation curve?
Goes gently along bottom/top then steeply rises/falls then gently along the top/bottom
Go over neutralisation reaction predictions.
