Unit 13 Acids and Bases Name: Perid: TEST: Wednesday 4/27/16 1
Unit 13 Acids and Bases Calendar Mnday Tuesday Wednesday Thursday Friday APRIL 7th Slutins Test 8 th Vide: Acids & Bases Ntes #1 Acids and Bases Characteristics and Arrhenius and Brnsted Lwry definitins HW: Pg. 6 11 Ntes: ph scale: HW: Pg. 9 12 G ver Gas Law, Bnding, and Slutins Tests 13 Cumulative TEST 14 ph and poh calculatins - Math Practice 15 Quiz?!?!?! Crsswrd puzzle Pg 13-14 HW: Study fr HW: Pg 12 Cumulative Exam Half day End f 5 th six weeks 18 19 20 21 22 PHET Cmputer Lab Titratins Pre Lab Titratins Titratins Neutralizatin and Titratin Ntes HW: Study Guide Pg 18-21 HW: Study Guide Pg 18-21 25 Alien Juice Bar Cmputer Lab HW: Pg 17 26 STUDY GUIDE DUE! Review 27 Acids & Bases TEST 2
Ntes #1: Intrductin t Acids and Bases Acid: Prperties f Acids: (lemn juice) Bth strng and weak Will cause indicatrs t change clrs A metal + an acid will prduce Single replacement reactin Acid + Metal + a Duble replacement reactin Acid + Base + a Examples: HCl, sda, cffee Naming Rules: ION TYPE ION ENDING ACID NAME BEGINNING ACID ENDING Plyatmic -ite NO hydr- beginning -us -ate NO hydr- beginning -ic Mnatmic -ide hydr- beginning -ic EX: Examples f Naming Binary Acids HCl HF HBr EX: Examples f Naming Ternary Acids H 2SO 4 Sulfate is the ply, s H 2CO 3 Carbnate is the ply, s H 2NO 2 Nitrite is the ply, s 3
Base: Prperties f Bases: (sap) Bth strng and weak Will cause an indicatr t clrs Examples: NaOH, sap, antacids, dran, bleach Naming Bases The easiest are the bases, since mst f these are hydrxides, cmpunds yu already knw hw t name. Metal hydrxides are named in the same way any ther inic cmpund is named. First give the name f the in. Fllw this with the name f the anin, which, in the case f bases, is. Mg(OH)2 - KOH Other definitins f Acids and Bases Arrhenius Acids and Bases: Acid:. Base:. Brønsted Lwry Acids and Bases They felt the Arrhenius definitin was t limiting. Acids: Brønsted Lwry Acids and Bases cnt. Bases: Ex: NH3 + H2O NH4 + + OH - EX: HCl + H 2O H 3O + + Cl - 4
Amphteric: Strng Acids/Bases: Ex: HCl, NaOH Weak Acids/Bases: Ex: NH 3, Acetic Acid (vinegar) Tth decay is caused by the weak acid lactic acid: C 3H 6O 3 Strng Electrlytes breaks apart int its ins Are cnductrs f electricity Will prduce a light bulb Examples f Acids and Bases that are Strng Electrlytes: Weak Electrlytes breaks apart int its ins Are cnductrs f electricity Will prduce a light bulb Examples f Acids and Bases that are Weak Electrlytes: 5
HOMEWORK DAY 1 NOTES Which picture at right is the: 1. Strng electrlyte 2. Weak electrlyte A B IDENTIFICATION - Identify the fllwing examples as: A = acid B = base S = salt (neither acid nt base) Remember frm the previus units, a salt is any inic cmpund, excluding what we classify as a base. 1. AgOH 2. MgSO4 3. ZnCO3 4. H2SO4 5. NaOH 6. HClO 7. Mg(OH)2 8. HNO3 9. Pb(ClO)2 10. (NH4)2CO3 11. HC2H3O2 12. HBr 6
ph SCALE Ntes: ph and poh MEASURING ph Scientists use a ph scale t measure the strength f an acid r base. The term ph stands fr ptential fr hydrgen. The amunt f hydrgen in a substance determines its acidity r alkalinity. Alkaline is anther term fr base. A number n the ph scale is used t describe the strength f acidity r alkalinity. The mst cmmnly used ph scale ges frm 1 (very acidic) t 14 ( very basic). The number 7 n a ph scale means neutral neither acid nr base. The cncentratin f hydrgen ins in a slutin is described by its number n the ph scale. A ph tells yu that the cncentratin f in is. EX: ph 2 By cmparisn, a ph tells yu that the cncentratin f in is. EX: ph12 Self-inizatin f water:. H2O + H2O OH - + H3O + Als written as: H2O H + + OH - The H3O + and H + represent hydrgen ins in slutin. Neutral Slutins In pure water, the cncentratin f hydrgen ins is t the cncentratin f hydrxide ins 1 x 10-7 M r ph f (Remember that M is the unit fr Mlarity) [H + ] = [OH - ] (brackets represent cncentratin) The represents a 7
Slutins In a slutin, if the [H + ] the [OH - ] and vice versa. Think back t ur see-saw. As ne persn ges up the ther persn ges dwn. In-prduct cnstant f water, Kw: K w = [H + ] x [OH - ] = 1 x 10-14 M Acidic Slutin: The [H + ] is than [OH - ]. Therefre, the [H + ] is Basic Slutin: The is [H + ] less than [OH - ]. Therefre, the [H + ] is A.k.a. Acids Bases Let s review: Cmplete the chart belw: Type f Slutin ph Ranges [H + ] versus [OH - ] Example Acidic Neutral Basic r Alkaline 8
Hmewrk: 1. Use the ph scale n page 7 t rank battery acid, vinegar, range juice, milk, and bleach in rder f increasing acidity. 2. Cmplete each sectin: 9
ph CALCULATIONS ph = - lg[h + ] ph [H + ] Kw = [H + ] [OH - ] Remember: The ph scale ranges frm 0-14 0 = 7 = 14 = ph = What is the ph f a neutral slutin? Calculate using the Lgarithmic functin n the calculatr ( see pht t the right) Sample Prblems As lng as yu have a x 10 t sme pwer, the ph is the expnent. If the number befre the x10 is anything ther than 1, yu MUST use the frmulas t find the ph. 1. What is the ph f the fllwing cncentratins? a. [H + ] = 1 x 10-2 M = b. [H + ] = 1 x 10-9 M = c. [H + ] = 1 x 10-5 M = 2. What is the ph f the fllwing cncentratins? Use ph = - lg[h + ] a. [H + ] = 2 x 10-2 M = b. [H + ] = 6 x 10-9 M = c. [H + ] = 3 x 10-5 M = 10
Other Frmulas and Prblems ph 14 = ph + poh (See example 1 belw) Using the Equilibrium cnstant labeled as Kw is Kw = EX: What is the ph f a slutin with a [OH - ] f 4.0 x 10-11 M? Use Kw t find [H + ] then find ph using lg functin. 1. If ph = 5, poh = Example Prblems Is this slutin acidic, basic r neutral? 2. What is the ph f a slutin that has a hydrgen in cncentratin f 1.0 x 10-5 M? Is this slutin acidic, basic r neutral? 3. What is the hydrgen in cncentratin f a slutin with a ph f 11? Which has a greater cncentratin: H + r OH -? 4. A slutin has a hydrgen in cncentratin f 1.2x10-8 M. Determine the ph f the slutin. Is this slutin acidic, basic r neutral? 5. Assuming Kw = 1x10-14, calculate the mlarity f OH- in slutins at 25ºC when the H+ cncentratin is 0.2M. 11
Hmewrk Practice Prblems n ph Slve the fllwing prblems. Be sure t shw wrk fr each prblem. 1. Determine the ph f a slutin that has a hydrgen in cncentratin f 1.0x10-9 M. Is this slutin acidic, basic, r neutral? 2. Lime juice has a hydrgen in cncentratin f 1.3x10-2 M, while the [H + ] in lemn juice in 0.067M. Calculate the ph fr each juice. ph f lemn = ph f lime = Which is mre acidic? 3. What is the hydrgen in cncentratin fr a slutin with a ph f 8? What is the poh f the slutin? 4. Knwing Kw = 1x10-14, calculate the mlarity f OH - in slutins at 25ºC when the H + cncentratin is: a. 5 x 10-10 M b. 100 M 5. Determine the ph f a slutin if the [OH ] = 4.93 10 8. (Hint: slve fr [H + ] using Kw, then ph) 12
REVIEW OF ACID/BASE PROPERTIES AND ELECTROLYTES WORD BANK crrsive strng dim slippery belw bright neutral all abve I Chemistry acidic weak hydrxide hydrnium metals amphteric acid(s) base(s) red blue hydrgen bitter sur electrlyte basic 13
Hints fr the Crsswrd Puzzle Acrss 4. able t act as an acid r base. 6. Bases have a taste. 9. slutins cntain hydrgen and hydrxide ins. 10. Acids will react with t prduce hydrgen gas. 14. Acids have a taste. 17. An acid r a base can be called a(n) because either can cnduct an electric current. 18. Fr a weak electrlyte, the light bulb will be. 19. the name f the in cmmnly fund in bases 20. A electrlyte will partially dissciate. Dwn 1. A electrlyte will cmpletely dissciate. 2. harmful, destructive, caustic 3. the type f slutin that has a higher hydrgen in cncentratin the hydrxide in cncentratin 4. Fruits and vinegar are examples f. 5. Bleach, ammnia, and sap are all examples f. 7. Bases feel. 8. Fr a strng electrlyte, the light bulb will be. 11. Fr bases, the ph is seven. 12. Bases turn litmus paper. 13. Fr acids, the ph is seven. 15. the clr f ph paper in an acidic slutin 16. the element cmmnly fund in acids 14
Neutralizatin Ntes Acid-Base reactins will prduce when cmpletely neutralized. Salts are cmpunds cnsisting f a(n) frm an acid and a(n) frm a base. In general, reactins in which an acid and a base react in an aqueus slutin t prduce a salt and water is called Neutralizatin Reactins. Neutralizatin ccurs when an Acid + Base + Salt: Anin frm acid and the catin frm the base jin tgether t frm a salt. Where d we see this prcess? Farmers cntrlling the f sil Frmatin f A strng acid + a strng base = neutral slutin Examples: HCl + NaOH H2O + NaCl HCl + KOH H2O + KCl Practice: Dn t frget t balance them after yu write them. HCl + LiOH HNO3 + CsOH HBr + KOH 15
Titratins Titratin: If yu dn t knw the cncentratin f ne slutin, yu can figure it ut by perfrming a neutralizatin reactin, r titratin, with a. A standard slutin is ne f. Perfrming Titratins Steps in a neutralizatin reactin: A measured vlume f an slutin f cncentratin is added t a flask. Several drps f are added t the slutin. Measured vlumes f a with a cncentratin are mixed int the acid until it barely changes clr. End Pint: Once yu have reached the end pint, yu can perfrm calculatins t find the unknwn slutin. 3. Example: A 25 ml slutin f H 2SO 4 is cmpletely neutralized by 18 ml f 1.0 M NaOH. What is the cncentratin f H 2SO 4 slutin? a. Step 1: Balance Equatin H 2SO 4 + NaOH Na 2SO 4 + H 2O b. Step 2: Use this frmula t slve fr unknwn cncentratin. = n a = number f f yur (Cefficient) n b = number f f yur (Cefficient) M = V = 16
Neutralizatin Reactins can als be asked like this: 1. Hw many mles f HCl are needed t neutralize 6 mls f KOH? a. 1 st ask, what is the ml rati and then set it up as a prprtin. 2. H2SO4 + 2NaOH Na2SO4 + 2H2O a. One mle f sulfuric acid is needed t neutralize mles f NaOH. b. Hw many mles f NaOH are needed t neutralize 4 mles f H 2SO 4? Neutralizatin and Titratin Hmewrk 1. What is the purpse f a titratin? 2. Why d yu need an indicatr in a titratin? 3. What is the endpint? 4. Why is it imprtant nt t versht the titratin? Refer t yur answer t #1. 5. Calculate the mlarity f an acetic acid slutin if 34.57 ml f this slutin are needed t neutralize 25.19 ml f 0.1025 M f sdium hydrxide. Balance the equatin as needed!!!! HC 2H 3O 2 (aq) + NaOH (aq) Na C 2H 3O 2 (aq) + H 2O (l) 6. 50 ml f 0.60 M sdium hydrxide neutralized 20 ml f sulfuric acid. Determine the cncentratin f the acid. BALANCE THE EQUATION FIRST! H 2SO 4 (aq) + NaOH <-> Na 2SO 4 (aq) + H 2O (l) 7. 25.0 ml f 0.10 M nitric acid neutralized 40.0 ml f barium hydrxide. Determine the cncentratin f the base. BALANCE! HNO 3 (aq) + Ba(OH) 2 (aq) <-> Ba(NO 3) 2 (aq) + H 2O (l) 17
Acid/Base STUDY GUIDE This is due n 4/26/16 and must be cmpleted in its entirety t earn +5 pints n the test. Acid and Base definitins: 18
1. What are the prperties f acids? 2. What are the prperties f bases? 3. Label as Acid (A), Base(B) r Salt(S) a. HCl b. H 3PO 4 c. HNO 2 d. LiOH e. H 2SO 3 f. H 3P g. Mg(OH) 2 h. NaCl i. KNO 3 4. What are the prducts f the self-inizatin reactin f water? 5. What des Kw stand fr? 6. What is the value f Kw 7. Write the equatin fr Kw: 19
8. Finish the equatins: ph = poh= ph + poh= 9. What is the range fr the ph scale? 10. What is the equatin used fr a titratin? 11. Write a cmplete and balanced equatin fr the fllwing acid-base reactin: a. H 3PO 4 + Ca(OH) 2 b. HCl + Mg(OH) 2 12. Calculate the cncentratin f hydrchlric acid if 125.0mL f this acid is neutralized by 60.0mL f 2.0M sdium hydrxide? HCl (aq) + NaOH (aq) H2O (l) + NaCl (aq) 13. Calculate the cncentratin f sulfuric acid if 60.0mL f this acid is neutralized by 10.0mL f.10m ptassium hydrxide? H 2SO 4 (aq) + KOH (aq) <-> K 2SO 4 (aq) + H 2O (l) 14. What is the mlarity f 3.50 L f slutin that cntains 90.0g f sdium chlride? 20
15. Hw many mles f HCl are present in 0.8 L f a 0.5M HCl slutin? 16. Hw many milliliters f 16.0 M HNO 3 wuld be required t prepare 750 ml f a 0.5 M slutin? 17. Cmplete the chart: remember Kw = [H+][OH - ] and ph = -lg[h+] and ph + poh = 14 Given Slve fr Acidic, Basic, r Neutral? (A/B/N) ph = 7 poh = poh = 12.5 ph = [H+] = 2.6 x 10-4 ph = [H+] = 1.0 x 10-8 ph = [OH - ] = 1.0 x 10-10 [H+] = [OH - ] = 5.2 x 10-3 [H+] = [H+] = 1.0 x 10-7 [OH - ] = [H+] = 9.1 x 10-13 [OH - ] = Kw = 1.00 x 10-14 (ml/l) 2 21