Unit 2 Flashcards
In a strong acid strong base titration, what is the pH at equivalence
7.00
In a weak Acid, strong base titration, what is the PH at equivalence
7.00> (more basic)
In a weak base, strong acid titration, what is the PH at equivalence?
7.00< (more acidic)
When does the PH = pKa in a titration?
At the halfway point to the equivalence point, meaning at half the added volume of acid/base
What is a polyprotic acid?
an acid that has more than one H+ to donate
Why is Na2CO3 a diprotic base
the CO3 has a 2- charge that allows it to accept the 2 H+
Why do the H’s on H3PO4 come off?
The extended oxygens are very electronegative and pull the electron density towards itself which weakens the bond between the O–H and creates partial charges
Which bonds are very ionizable?
O-H, N-H, H-F
What does a small ka do to an acids ionizability
the smaller ka, the more difficult it is to lose H+ (less acidic, weakest acid)
What is the rule for calculating the pH of a polyprotic acid
When the Ka’s differ by 1000 >, we can calculate the PH from the first ionization reaction
What does the strength of a binary acid depend on
Electronegativity of Y
Bond strength
Which way does acid strength increase across a periodic table
It increases left to right due to increasing electronegativity (doesn’t dissociate as much, the H+ is held more tightly technically a weaker acid because it doesn’t dissociate as much)
What is the trend of bond strength?
It decreases down a row, the acid more weakly held/stronger acidity
What factors affect Oxyacids
Electronegativity of Y and the # of oxygens attached
If the electronegativity is higher on an oxyacid nonmental, is it more acidic (does it dissociate more?/stronger acid)
It is more acidic
the electron density is held near the nonmetal, meaning the H+ is held less tightly
If a oxyacid has more oxygen what happens
it is more acidic
adding terminal oxygen atoms causes electrons to be drawn away from the O–H bond,
What are Lewis Acids and bases
they are focused on the transer of the electron pair from a base to an acid
Definition of Lewis Acid
A cation/neutral molecule that is e- deficient (in its octet)
Defintion of Lewis base
an anion/neutral molecule with an electron pair
WHat is the common ion effect
it is the suppression of the solubility of a solid when it is placed in a solvent that possesses one of its ions
What is true about the PH effect on solubility and basic anions?
If a salt has a basic anion (strong or weak), it will dissolve BETTER in an acid than in h20 (Acid Base reaction)
What happens to the solubility if a salt with a basic anion is submerged in a basic solution?
When is a solution undersaturated and will not form a ppt?
when Q<ksp
When is a solution saturated and just starts to form ppt
when Q=Ksp
these salts with basic anions have greater solubility in water (CaCO3, PbF2, Ca3(PO4)2; why?
they form their conjugate acids in water (acid base reaction)
How is Q used in precipitation?
the value of Q helps us predict if the reaction will form a ppt or not
What does a smaller ksp mean for solubility?
It is less soluble, but it is more likely to form a ppt first
What is a complex ion
contains a transition metal bound to 1 or more small molecules or ions (NH3, H20, OH-, F) called ligams
why is the K value of a complex ion high?
It is very stable
