Chemistry Of Acids

Question 1

What are the common acids and alkalis?

Answer 1

Acids
Hydrochloric
Sulfuric
Nitric 
Ethanoic
Alkalis
sodium hydroxide
Ammonia
Potassium hydroxide

Question 2

What is an acid?

Answer 2

A substance with a pH of less than 7 that forms H+ ions in water

Question 3

What is an alkali?

Answer 3

A substance with a pH of more than 7 that forms OH- ions in water

Question 4

How do molecules dissociate/ionise in strong and weak acids?

Answer 4

Strong
ALL molecules ionise

Weak
ONLY A SMALL AMOUNT of molecules ionise

Question 5

What’s the difference between an alkali and a base?

Answer 5

An alkali is a soluble base

Question 6

The reaction between an acid and an alkali is called…

Answer 6

Neutralisation

Question 7

What is the ionic equation for neutralisation?

Answer 7

H+ + OH- -> H2O

Question 8

What is pH?

Answer 8

The concentration of H+ ions in a solution

Question 9

How is the Cannes in H+ ion concentration calculated?

Answer 9

Factor H+ ion concentration changed by 10^-x

where x=difference in pH

Question 10

What indicator is used in titration and what is the colour change?

Answer 10

Phenolphthalein

Pink -> colourless

Question 11

What is the method of titration?

Answer 11

• neutralisation
• unknown volume in burette, known in conical flask
• phenolphthalein added (2-3 drops)
• unknown added drop by drop until colour change seen
• repeated to find mean volume

Question 12

Calculating concentration in g/dm^3

Answer 12

Concn = mass/volume

Question 13

Calculating concentration in mol/dm^3 formula

Answer 13

Concn = moles/volume

Question 14

Formula to convert concn in moles to concn in g

Answer 14

Concn (g) = concn (moles) x Mr (compound)