Chemistry Day 80 P. 4: Monday, May 6th, 2019 P. 5: Wednesday, May 8th, 2019

Do-Now: “BrainPOP: Acids & Bases” 1. Write down today’s FLT 2. The pH scale ranges from ____ to ____. 3. Which is more acidic: pH 3 or pH 6? 4. Which is more basic: pH 3 or pH 6? 5. If you have a pH of 3, what is your pOH? 6. What is the pH of a solution if the [H+] is 1.5 x 10-6 M? Show all steps. 7. Take out your planner and ToC

Announcements• APTestingstartsthisweek!Berespectfulofnoisearoundtestingareas

Planner:•  QuizonKinetics/Acids+Basesnextclass•  Study!Unittest:Thermo,Spontaneity,Kinetics,Acids/Bases

Table of Contents #3: 17.  BrainPOP: Acids and Bases 18. Acids/Bases CN Part C 19. Acids/Bases WS C

BrainPOP:Acids&Bases• WatchtheBrainPOPvideo• Afterthevideo,answerthequestionsinyourgroup–everymembermustcopydownthesameanswer

• Thegroupwiththemostcorrectanswersà+5dojopointseach

https://www.brainpop.com/science/matterandchemistry/acidsandbases/

FLT•  Iwillbeabletodefinestrongacidsandweakacids&definetheproductsofanacid-basereactionbycompletingCh.16CNpartC

Standard HS-PS3-1:Createacomputationalmodeltocalculatethechangeintheenergyofonecomponentinasystemwhenthechangeinenergyoftheothercomponent(s)andenergyflowsinandoutofthesystemareknown

Acid/BaseStrength&Neutralization

Recall

Recall •  The pH scale ranges from 0-14 •  What’s more acidic? •  What’s more basic?

Recall •  Brønsted-Lowryacids:

– DonateH+

•  Brønsted-Lowrybases:– Accept H+

Recall •  Acids and bases are

electrolytes •  This means that they

dissociate into ions in water

Recall •  What if they only dissociate a little bit?

Electrolytes and Nonelectrolytes •  Weakelectrolytes=onlypartiallyionizeWeakelectrolyteshaveonlyafractionofthesolutethatexistsasions(about1%)– Weakacidsandbases;ammonia,aceticacid

Acid/BaseStrength

Acid/Base Strength •  Acids are classified as strong or weak

depending on the degree to which they ionize in water

Acid/Base Strength •  Strong acids = completely ionize in water •  Ex/ HCl, HNO3, H2SO4

HCl(g) + H2O(l) à H3O+(aq) + Cl-(aq)

100% ionized

Acid/Base Strength •  Weak Acids = ionize only slightly in water. •  Ex/ Ethanoic (acetic) acid CH3COOH and

HF CH3COOH(aq) + H2O(l) ßà H3O+

(aq) + CH3COO-(aq)

Acid/Base Strength •  Bases are also classified as strong or weak

depending on the degree to which they ionize in water

Acid/Base Strength •  Strong bases = completely dissociate

into metal ions and OH- ions in water •  Ex/ Ca(OH)2, NaOH, KOH

Acid/Base Strength •  Weak Bases = Produce a small amount of

OH- in water •  Ex/ Ammonia (NH3)

NH3(aq) + H2O(l) ßà NH4+

(aq) + OH-(aq)

99% NH3 still present, ~1% ionized

ConjugateAcids&Bases

TheBrønsted-LowryDefinition•  Wecanlabelouracid-basereactionsusingproton-transfer

•  Ex1:

HCl(aq)+H2O(l)àH3O+(aq)+Cl-(aq)

•  Ex2:

NH3(aq)+H2O(l)ßàNH4+(aq)+OH-

(aq)

Donated(Lost)H+

Donated(Lost)H+

Accepted(gained)H+

Accepted(gained)H+

Acid

Acid

Base

Base

Conjugate Acids & Bases •  In this equation, what is the acid? What is

the base?

Conjugate Acids & Bases •  Note: This is a reversible reaction. The back

reaction is also an acid-base reaction. •  Which is the acid and which is the base?

Conjugate Acids & Bases •  Conjugate Acid = formed when a base

gains H+

Conjugate Acids & Bases •  Conjugate Base = formed when an acid

loses H+

TheBrønsted-LowryDefinition•  Wecanlabelouracid-basereactionsusingproton-transfer

•  Ex1:

HCl(aq)+H2O(l)àH3O+(aq)+Cl-(aq)

•  Ex2:

NH3(aq)+H2O(l)ßàNH4+(aq)+OH-

(aq)

Donated(Lost)H+

Donated(Lost)H+

Accepted(gained)H+

Accepted(gained)H+

Acid

Acid

Base

Base

Conj.acid

Conj.base

Conj.acid

Conj.base

Try This: •  In the equation below, label the acid, base,

conjugate acid, and conjugate base.

HNO3(aq) + CH3OH ßà CH3OH2+

(aq) + NO3-(aq)

Donated(Lost)H+

Acid Conj.base

Base Conj.acid

Accepted(gained)H+

Conjugate Acids & Bases •  Conjugate Acid-Base Pair Strengths:

– Strong acids/bases form weaker conjugates – Weak acids/bases form stronger conjugates

LastTidbits

Last Tidbits •  Amphoteric substances = act as both an

acid or a base

NH3 + H2O ↔ NH41+ + OH1-

base acid c.a. c.b. HCl + H2O ↔ H3O1+ + Cl1-

acid base c.a. c.b.

Last Tidbits •  Neutralization Reaction - a reaction in

which an acid and a base react in an aqueous solution to produce a salt and water:

HCl(aq) + NaOH(aq) à NaCl(aq) + H2O(l)

H2SO4(aq) + KOH(aq)à ?

Last Tidbits • Acid + Base à Water + Salt •  Properties related to every day:

– antacids depend on neutralization – farmers adjust the soil pH – formation of cave stalactites – human body kidney stones from

insoluble salts

Pair-Share-Respond1.  Distinguishbetweenstrongandweakacids

2.  Distinguishbetweenstrongandweakbases

3.  Whatareconjugateacids?4.  Whatareconjugatebases?5.  Howcanyoudetermineifyourconjugateacid/baseisstrongorweak?

Chemistry Day 81 Tuesday, May 7th – Wednesday, May 8th, 2019

Do-Now: “Kinetics/Acids/Bases Quiz Day Do-Now” 1.  Write down today’s FLT 2.  What is the formula for pH? 3.  How do you determine how many decimal

places your pH should have? 4.  Distinguish between the acids “hydrosulfuric

acid” and “sulfuric acid” 5.  Copy the equation: H2CO3 + H2O à H3O+ +

HCO3-

6.  Identify the base and conjugate base in the reaction in #5. Use work/labeling to justify your choices.

Chemistry Day 82 Thursday, May 9th – Friday, May 10th, 2019

Do-Now: “Unit Test Day Do-Now” 1.  Write down the FLT 2.  How do you determine how many decimal

places your pH should have? 3.  Distinguish between the acids “sulfuric acid”

and “sulfurous acid” 4.  How can you use an energy diagram to

determine if your reaction is exo- or endothermic?

5.  Distinguish between temperature at STP and temperature at standard conditions

6.  Take out your planner, reference sheet, and ToC