acids and bases

Question 1

acids

Answer 1

substances that are able to produce H+ ions when dissolved in water. Cause litmus to go red, phenolphthalein to go colourless and methyl orange to go red

Question 2

bases

Answer 2

substances that can neutralise acids

Question 3

alkalis

Answer 3

soluble bases that produce OH- ions when in water. They cause litmus to go blue, phenolphthalein to go pink and methyl orange to go yellow

Question 4

bronsted lowry definitions

Answer 4

acids are proton H+ donors
bases are proton H+ acceptors

for a species to act as an acid it must contain a hydrogen atom attached by a bond which can be easily broken

for a species to act as a base it must contain a non bonding e- pair which it csn use to form a coordinate bond with an H+ ion.

Question 5

conjugate acids and basses

Answer 5

when an acid donates H+ the species produced is called a conjugate base as it now has the ability to accept an H+

when a base gains H+ the species produced is called a conjugate acid as it now has the ability to donate an H+

the stronger the acid the weaker the conjugate base it produces and the weaker the acid the stronger the conjugate base

Question 6

amphiprotic

Answer 6

substances (eg water) which are able to either donate or accept a H+ and so act as either an acid or a base are said to be ampiprotic

Question 7

amphoteric

Answer 7

a substance that can act as either an acid or a base. this is a more general term as not all acids lose or gain H+ ions.

Question 8

strong and weak acids in aqueous solution

Answer 8

strong acids ionise completely in aqueous solution
weak acids partially ionise in aqueous solution

strong acids therefore have higher concentrations of hydrogen ions in aqueous solution when compared to a weak acid of the same concentration

Question 9

experimental determination of strength of acids

Answer 9

1. conductivity: strong acids are able to conduct electricity much better than weaker acids
2. by reaction with Carbonates: the one that produces CO2 at the greatest rate is the strongest.
3. pH: the lower the pH value, the higher the concentration of H+, the stronger the acid

Question 10

pH

Answer 10

pH stands for power of hydrogen

pH = -log10[H+]