Acids

Acid Dissociation Constant Ka

Acid Dissociation Constant Ka: Tells us extent of dissociation. No Ka value for strong acid as completely dissociate. Units are moldm-3. Ka = [ H +(aq)][ A−(aq)] [ HA(aq)] Use this one if Q asks for Ka expression.  Equilibrium Constant: Ka changes with temperature so...

read more

pH of Weak Acids

Ka can be calculated from equilibrium amounts.  Approximations: Equation above can be simplified to equation below by assuming two things…  Dissociation of Water: There is a small concentration of H+ from dissociation of water which is neglected. Therefore when HA...

read more

pH of Bases

Determine if acid or alkali.  Check if weak or strong before doing method.  Also always check if 2OH or 2H as would be dibasic and would need to multiply conc x 2.  Check in questions if given pKa or Ka.  Kw: Ionic product of water- the ions in water H+ and OH-...

read more

Bronsted- Lowry Acids and Bases

Acid: An acid dissociates and releases H+ ions in aqueous solution. A Bronsted- Lowry acid is a proton donor.  A strong acid completely dissociates AND a weak acid partially dissociates.  Can measure current through an acid to determine if strong and weak acid....

read more

pH Scale and Strong Acids

pH Scale: Uses negative logarithm of powers of 10. More manageable scale.  H Ion Concentration: Low value of [H+ (aq)] = high value of pH. A change in one pH number is 10x the [H+ (aq)].  Measuring pH: The electrode in pH meter measures electrical potential of H+...

read more