Acids And Bases And Buffers Flashcards
Strong and weak acid meaning
Fully dissociate and partially dissociates
Bronsted lowery acid
Proton donor
Bronsted lowery base
Proton acceptor
Why is H2O not used in equation
Effectively constant
KW
[H+][OH-]
How to work out usually PH
1 . 1:1 ratio so H^2 so square root KW to find H put in PH equation
2. Divide OH concentration by KW to find H+ and put in PH equation
If KW not given usually 1 * 10^ 14
Why does KW increase as temperature increases
Forward reaction is endothermic as as temperature increase equilibrium shifts to the right hand side to oppose increase in temperature
PH
-log10(H+)
KA for acids
Ka = (H+)^2
———-
Concentration of acid
KA for buffers
KA = (H+)(Salt)
————-
Concentration of acid
What happens to original moles in buffer when acid is added
H+ react with salt so equilibrium shifts to left hand side to increase in acid moles and decrease in salt moles
What happens to original moles when an alkali buffer is added
( opposite of acid )
Decrease in acid moles
Increase in salt moles
Equation for when acid acts as an base
Looses an hydrogen
Acid acts as weak acid
Use reversible signs
Dissociates into H+ and …..
Why PH is nuetral
H+ = OH-
Using a burette, 26.4 cm³ of 0.550 mole decimetres cubed of sulphuric acid were added to a chronicle flask containing 19.60 cm³ of 0.720 mole decimetres cubed aqueous sodium hydroxide calculate the pH of the solution formed.
- Calculate moles of each thing ( times acid by 2 as 2 H+ in H2SO4)
- Substract by lowest moles
- Divide by total volume to get concentration
- Put into PH equation
