Chem ch 16 Flashcards
Bases and acids are __________
Opposites
pH - what does it mean?
Power of Hydrogen (regarding solutions)
Measures Hydrogen ions
pOH – what does it mean?
Describes hydrogen ion concentration
Measures Hydroxide ions
What is the pH and pOH scale based on?
(hint: HijklmnO)
Ionization constant of water
What does the pH scale tell you?
How acidic or basic/alkaline a substance is
What does the pOH scale tell you?
Hydroxide ion concentration
pH = 7 what does that tell you?
Neutral solution
pH <7 - what is it?
Acid
pH >7 - what is it?
Base
pOH <7 - what is it?
Base
pOH >7 - what is it?
Acid
pOH =7 - what is it?
Neutral
Strong acid
Give up protons (H+) easily
Ionize completely (not shared!)
Dissolves well in water
Ex: HCl (stomach acid)
Weak acid
Don’t dissociate (separate) completely into ions
Dissolves poorly in water
Ex: Vinegar
Strong Base
Accept protons (H+) readily
Dissolves well
Ex: NaOH (dissolve 95%)
Weak Base
Poor proton (H+) acceptors
Doesn’t dissolve well
Ex: NH3 (dissolve 5%)
Acid + base -> _________+____________
H2O + Salt
If you look at a glass of water, are 100% of the water in there is H2O?
No there is self-ionization meaning water can react with itself and form different combinations
Conjugate base – how is it formed? What is it?
Everything tht remains of the acid molecule after a proton (H+) is lost
Acid (loses H+) –> conj base
Conjugate acid – how is it formed? What is it?
Formed when the proton (H+) is transferred to the base
Base (gains H+) –> conj acid
Oh my lady gaga you spilled base on your arm! How do you respond to neutralize it?
Put acid on it
Titrations – what are they
Controlled neutralization reactions used to determine the unknown concentration of a solution
Equivalence point – what is that?
Equal moles of acid and base (in a titration)
End point – what is that?
The point in a titration at which the indicator changes color (when pH 7.0 is met - true for strong acids and bases only)
MaVa = MbVb <– what does this formula tell you? How do you use it?
Equation for solving unknown MOLARITY concentrations (M)
known known = unknown unknown
Buffer – what is it? How many times do you need to poke someone else before they react? (Think about class!)
Solutions tht resist changes in pH (balance pH)
Cancels out acids/bases
Weak acid & conj base OR Weak base & conj acid
Most effective @ regulating SLIGHT pH changes
Ex: Human blood btwn pH 7.35-7.45
Bronsted-Lowry acid and base – how are they defined?
Acid donates a proton (H+) (deprotonation)
Base accepts a proton (protonation)
Arrhenius Model
Acids release H+ (hydrogen) into solutions
Bases release OH- (hydroxide) into solutions
Problem: Hydrogen-containing compounds are not always acids - only deals w compounds in aqueous solutions
Lewis Model
Acid - substance tht accepts pair of electrons
Base - substance tht donates a pair of electrons
Broader definition
How do we measure pH?
Universal indicators (substances whose colors are sensitive to pH)
Ex: pH meters, papers
Base characteristics
Bitter
Feels slippery
Some are electrolytes (substance that ionizes [+ -] to conduct electricity in a solution)
pH above 7
Acid Characteristics
Sour
Electrolyte
React w active metals to produce Hydrogen gas and a salt
pH below 7
