Acids and Alkalis Flashcards
(27 cards)
What does metal + acid form?
Salt + hydrogen
What does metal oxide + acid form?
Salt + water
What does metal hydroxide (alkali) + acid form?
Salt + water
What does metal carbonate + acid form?
Salt + water + carbon dioxide
What does ammonia + acid form?
Ammonia salt
What is an acid?
An acid is a substance that has a pH lower than 7 on the pH. And releases H+ ions.
What is the difference between strong and weak acids?
A strong acid fully ionises in solutions (the ions fully separate). In a weak acid, the ions only partially separate, they don’t fully ionise).
What is an alkali?
An alkali releases OH- ions in solutions and has a pH higher than 7.
What is the difference between strong and weak alkali?
A strong alkali is completely ionised and weak are partly ionised.
What are properties of acids?
☆They have a sour test taste when edible like lemon and vinegar
☆They are corrosive
☆When they are added to water they form positively charged hydrogen ions (H+)
☆ Presence of positively charged hydrogen ions is what makes the solution acidic
What is the formula for hydrochloric acid?
HCl
What is the formula for nitric acid?
HNO(3)
What is the formula for sulphuric acid?
H(2)SO(4)
What are the properties of alkalis?
☆They are soluble (able to dissolve) in water
☆They feel soapy to the touch and taste bitter
☆They are usually oxides or hydroxides of metals
☆The presence of the negatively charged hydroxide ions is what makes aqueous solutions alkali.
What is the formula of Calcium hydroxide?
Ca(OH)2
What is the formula of sodium hydroxide?
NaOH
What colour does litmus solution turn in acid?
Red
What colour does litmus solution turn in alkali?
Blue
What colour does methyl orange turn in acid?
Red
What colour does methyl orange turn in alkali?
Yellow
What does universal indicator turn in acid?
Red
What does universal indicator turn in alkali?
Purple
What does universal indicator turn in neutral substance?
Green
What is an indicator?
It determines if a substance is a strong/weak acid or alkali by changing colour. It can only give an approximate measure and is useful when estimating the pH of an unknown solution.
