Exam (4/22) Flashcards
What do acids and bases form in aqueous solutions?
Electrolytic aqueous solutions
How do bases and acids taste?
Bases taste bitter, acids taste sour
What is the texture of bases and the effect of acids on metals?
Bases are slippery, acids are corrosive
What color change occurs with litmus paper when testing acids and bases?
Bases turn red litmus blue, acids turn blue litmus red
What color does phenolphthalein turn in bases and acids?
Base turns pink, acid colorless
What is the result of an acid-base neutralization reaction?
Acid + Base → Salt + Water
What is the pH range for acids and bases?
Acids: pH < 7, Bases: pH > 7
According to the Arrhenius definition, what does an acid release?
H+ ions in an aqueous solution
According to the Arrhenius definition, what does a base release?
OH- ions in an aqueous solution
What is the Bronsted-Lowry definition of an acid?
Any species that can donate a proton
What is the Bronsted-Lowry definition of a base?
Any species that can accept a proton
What characterizes weak acids in terms of equilibrium?
Weak acids exist in equilibrium
What does a larger Ka value indicate about an acid?
The stronger the acid
What are the seven strong acids that must be memorized?
HCl, HBr, HI, H2SO4, HNO3, HClO3, HClO4
What does it mean for strong acids to dissociate completely?
Only single arrow reactions occur
How do weak bases behave in terms of equilibrium?
Weak bases exist at equilibrium
What characterizes strong bases in terms of dissociation?
Strong bases dissociate completely
What ions combine with hydroxide to form strong bases?
Alkali metals, Ca2+, Ba2+, Sr2+
What are polyprotic acids?
Acids with multiple H+ ions that can dissociate
How does the Ka value change as protons are lost from polyprotic acids?
Ka value gets smaller as each proton is lost
What is the relationship between strong acids and their conjugate bases?
Strong acids have weak conjugate bases
What is the relationship between weak acids and their conjugate bases?
Weak acids have strong conjugate bases
What are amphoteric substances?
Substances that can act as both acid and base
How do you name bases?
Add “hydroxide” after the cation name
What does pH measure?
Concentration of H+ ions in solution
What is the formula for calculating pH?
pH = -log [H+]
What does a one unit change in pH represent?
10x concentration change of H3O+ ions
What does pOH measure?
Concentration of OH- ions in solution
What is the formula for calculating pOH?
pOH = -log [OH-]
What is the relationship between pH and pOH?
pH + pOH = 14
How do you find the pH of a base?
Find pOH and subtract from 14
What factors affect the pH of weak acids?
Dependent on both Ka and concentration
What are indicators and their role in titrations?
Weak acids or bases that change color at different pH levels… Signal endpoint of a titration
What is the technique used to determine the concentration of an unknown acid or base?
Titration through a neutralization reaction
What is the endpoint in a titration?
When the indicator changes color
What is the neutralization reaction equation?
Acid(aq) + Base(aq) → Salt(aq) + Water(l)
What is the equivalence point in a titration?
When moles of H+ and OH- are equal
What is the pH of a neutralized substance?
Not always equal to 7
What is the pH of a strong acid and strong base neutralization?
pH = 7
What is the pH of a strong acid and weak base neutralization?
pH < 7
What is the pH of a weak acid and strong base neutralization?
pH > 7
What should be assumed in neutralization calculations?
Assume complete dissociation
What is a buffer solution?
Resists pH change when acid or base added
What must a buffer consist of to maintain pH range?
A weak conjugate acid-base pair
How do buffers act in a solution?
Act as a ‘sponge’ for [H3O+] or [OH-]
Henderson Hasselbach Equation
pH = pKa + log10( [A−] / [HA] )
Neutralization Calculations
MAVA = MBVB
What does ‘releasing hydroxide ions’ mean?
It’s asking which acts as a base
Double replacement formula
AB+CD = AD + CB
How does pH affect [H3O+] ions?
When pH increases [H3O+] ions decrease, making it more basic (Less acidic)
How does pH affect [H3O+] ions?
When pH decreases [H3O+] ions increase, making it more acidic
What is the relationship between pH and hydronium ions?
Higher pH = Fewer hydronium ions = More basic, Lower pH = More hydronium ions = More acidic
What is an Arrhenius acid?
Releases [H+] ions
What is an Arrhenius base?
Releases [OH-] ions
What pH values do acids, bases, and neutral substances have?
Acids: pH < 7, Bases: pH > 7, Neutral: pH = 7
What does a one unit change in pH mean?
A tenfold (10x) change.
What indicator is used for strong acid + strong base titrations?
Bromthymol blue, phenolphthalein
What indicator is used for strong acid + weak base titrations?
Methyl orange
What indicator is used for weak acid + strong base titrations?
Phenolphthalein
