Strong and Weak acids

Question 1

what happens when acid molecules ionise (split)?

Answer 1

In aqueous solutions, acid molecules ionise and release hydrogen ions e.g. HCL —> H+ + Cl-

Question 2

what is a strong acid?

Answer 2

strong acids fully ionise in water and all acid particles dissociate to release H+ ions. You can tell this when the arrow only goes in one direction.

Question 3

what are 3 examples of strong acids?

Answer 3

•hydrochloric acid:
HCL(aq) —> H+(aq) + Cl-(aq)
•sulfuric acid:
•H2SO4(aq)—> 2H+ + SO4^2-(aq)
•nitric acid:
HNO3(aq)—> H+(aq) + NO3(aq)

Question 4

what are weak acids?

Answer 4

•weak acids only partially ionise in water. Only a small proportion of acid particles dissolve to release H+ ions.
•You can tell if an acid is weak by the reversible arrow as the ionisation of an acid is weak and reversible which sets up an equilibrium between the unassociated and dissociated acid. The equilibrium lies well to the left

Question 5

what are 3 examples of weak acids?

Answer 5

•carbonic acids
•ethanoic acid
•citric acid

Question 6

what is the relationship between the pH of an acid or alkali and the concentration of Hydrogen ions?

Answer 6

The pH of an acid or alkali is a measure of the concentration of H+ ions in the solution

Question 7

How do the concentration of hydrogen ions increase as pH decreases?

Answer 7

for every decrease of 1 on the pH scale, the concentration of H+ ions increases by a factor of 10.

Question 8

what is the difference between the concentration of an acid and the strength?

Answer 8

•the strength tells you what proportion of acid molecules ionise in water
•concentration measures how much acid there is in a certain volume of water( how watered down the acid is) e.g. the larger the amount of acid in a certain volume of liquid the more concentrated the acid is