Acids and bases Flashcards
Name the 4 strong acids.
Sulphuric acid H2SO4
Nitric acid HNO3
Hydrochloric acid HCL
Phosphoric acid H3PO4
What is an acid ?
A proton donor
What is a base ?
A proton acceptor
What is the difference between a strong and weak acid ?
Strong acid fully dissociates.
What is ph ?
-log [H+]
What is produced when an acid reacts with a metal ?
Salt and hydrogen
What is produced when an acid reacts with a metal oxide ?
Salt and water
What is produced when an acid reacts with a metal hydroxide ?
Salt and water
What is produced when an acid reacts with a metal carbonate ?
Salt, water and carbon dioxide
What is produced when an acid reacts with ammonia ?
ammonium salt
How do you go from [H+] to ph ?
10^-ph
How do you calculate ph of a weak acid ?
Ka = [H+][A-} / [HA]
[H+] = [A-]
rearrange for [H+]
use -log[H+]
Why cant you use Ka to calculate ph of a strong acid ?
Because strong acid fully dissociates
How do you calculate pKa ?
-log Ka
How do you calculate Ka from pKa ?
Ka = 10^-pKa
What is Kw and how do you calculate it ?
Ionic product of water
Kw = [H+][OH-] or [H+]^2
Even though the PH water can be values other than 0 why is it still not acidic/alkaline ?
Because the concentration of the H+ ions is equal to the concentration of OH- ions
What is the value of Kw at room temp ( 298k ) ?
1x10^-14
What is the equation for the dissociation of water ?
H2O <-> H+ + OH-
Why does changing the temperature of water change the PH ?
increasing the temperature shifts the equilibrium towards the right hand side (breaking bonds is endothermic ) the change in the position of the equilibrium changes the PH
How do you find the PH of a strong base ?
Find the concentration of the base and find the concentration of the OH- ions rearrange Kw = [H+][OH-] to find conc of H+ and use -log
On a acid base titration graph what indicates if there is a weak base/acid present ?
curve at the start/end of the graph
Where is the neutralization point on a acid base titration graph ?
halfway up on the equivalence point
How do you know if a indicator is suitable for a reaction ?
The colour change ph is on the equivalence point.
