Flashcards
SCH4U Acid-Base Equilibrium
Flashcards do conjunto (18)
- 1Arrhenius Acid and Base- Acid = species that increases hydrogen ion concentration in solution
- base = species that increases OH ion concentration in solution
- limited theory since requires acid/base solutions to be aqueous - 2Neutralization-Arrhenius acid reacts with an arrhenius base to yield water and a salt
- Solution is neutral when [OH]=[H3O] - 3Mono/di/tri/polypotic-mono=species which can donate 1 proton
- diprotic= species which can donate 2, tri=3
-polyprotic= donor of multiple protons (more than 1); ex phosphoric acid (H3PO4) - 4Bronsted-Lowry acid/base-acid=any species that can donate a proton
base=any species that accepts a proton
- always classified for a specific reaction - 5Amphoteric / amphiprotic- substance that acts as both a Bronsted-Lowry acid and base
- example: water (because it auto-ionizes into H3O which is an acid and OH which is a base) - 6Conjugate acid-base pair- 2 species which differ by a single proton
- 7Acid- ex: orange juice, yogurt
- tend to react with metals to yield H2+salt
- react with carbonates to yield salt, water +CO2
- conductive
- taste sour, sting
- strong acids ionize quantitatively
- weak acids only partially ionize and the conjugate base of a weaker acid is stronger - 8Base- Ex: bleach, soap
- carbonates and bicarbonates are specific bases that react with acids to produce CO2+salt+water
- taste bitter, feel slippery
-strong bases (all hydroxides of group 1 metals) dissociate completely
- weak bases have weaker proton attractions and don't fully ionize - 9Gilbert-Lewis Theory- acid = any substance that can accept a pair of non-bonding electrons
- base = donor of a pair of non-bonding electrons - 10Indicators- Litmus paper --> red in acidic solution, blue in basic
- Universal indicator --> changes colour depending on pH
- pH meter --> measures voltage of a solution to determine conductivity; more conductive = higher acidity since that indicates more protons - 11Percent ionization-measure of how fully the acid ionizes into hydrogen ions
- useful to measure strength of an acid
- higher percent ionization = stronger acid - 12Acid ionization constant (Ka)- quantifies extent to which a weak acid ionizes in solution
- larger Ka value = greater concentration of product = stronger acid
- since a weak acid yields a strong conjugate base, the reaction is reversible, thus equilibrium can be reached **for strong-strong, the reaction is quantitative and is not an equilibrium reaction--> solve using basic stoichiometry** - 13End point vs Equivalence point- End point = when we see a change in colour; caused by changing the bond configuration/structure of the analyte by exposing it to more H or OH, leading to different light absorbency
- equivalence point is when hydrogen ion concentration = OH ion concentration. However, the solution may still be basic/acidic, because salts produced may be acidic or basic themselves - 14Strong acid strong base titration*consider example of titrating an acid with base* *quantitative rxn*
- before any base is added: concentration of solution = concentration of H ions, plug into pH=-log(H)
- once some base is added before equivalence: determine moles of H and moles of OH, find the difference between them to determine excess moles of H, use c=n/v to determine concentration of H
- at equivalence: no excess H or OH, pH is equal to 7
- after equivalence: find moles of excess NaOH, use c=n/v then plug into pOH formula and do 14-pOH to find pH - 15Weak acid-strong base (or vice versa)- before any base is added: use ice table to determine hydrogen ion concentration; Use Ka value to determine x which represents H concentration
- before equivalence once some base was added: find moles of each, determine which one is excess moles, then use c=n/v to find concentration. at this point, pH depends on the ionization of the weak acid, so use the same ice table of the weak acid, but this time the [acid] is the unreacted concentration (which you determined in last step using excess moles). The conjugate base is the concentration of base already produced, calculated based on the moles of base you found / total volume. The final column is the hydrogen ion concentration that will start at 0. Use this ice table and the Ka value to determine H ion concentration
- At equivalence: pH depends on dissociation of strong conjugate base. Determine the Kb of the base. The moles of conjugate base = the moles of acid (assuming 1 to 1 ratio), divide this by total volume to find concentration. Use this concentration as the initial in the ice table and solve for OH ion concentration. - 16Buffered solution- solution that resists a change in pH when small amounts of acid or base are added
- 17Buffer- mixture of conjugate acid-base pair in a salt (either a weak acid and its conjugate base salt or a weak base and its conjugate acid salt)
- resists change in pH since it's a pair of chemicals; one chemical neutralizes excess acid, one neutralizes excess base and they produce each other in the process - 18Buffer capacity- limit to amount of strong acid/base a buffer is able to neutralize before a drastic change in pH
- depends on concentration of acid/base pair; generally can resist + or
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- Descrição
- FlashCards sobre SCH4U Acid-Base Equilibrium, criado por Isabelle Poulin em 18-06-2018.
- Criado por
- Isabelle Poulin
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