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4/28 PRE-AP THE ACID/BASE POSTER RUBRIC FROM THE SIDE TABLE AND A BLANK PIECE OF PAPER TODAY YOU WILL MAKE A POSTER OVER ACIDS AND BASES AS AN INTRODUCTION.

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Presentation on theme: "4/28 PRE-AP THE ACID/BASE POSTER RUBRIC FROM THE SIDE TABLE AND A BLANK PIECE OF PAPER TODAY YOU WILL MAKE A POSTER OVER ACIDS AND BASES AS AN INTRODUCTION."— Presentation transcript:

1 4/28 PRE-AP THE ACID/BASE POSTER RUBRIC FROM THE SIDE TABLE AND A BLANK PIECE OF PAPER TODAY YOU WILL MAKE A POSTER OVER ACIDS AND BASES AS AN INTRODUCTION ASSIGNMENT AND THEN WE WILL START THE ACID/BASE UNIT. IF TIME PERMITS, WE WILL DO A QUICK LAB OVER ACIDS AND BASES. IF NOT, WE WILL PERFORM THIS LAB TOMORROW. THERE WILL BE A QUIZ ON MONDAY OVER THE SOLUBILITY RULES YOU RECEIVED LAST WEEK. ON THAT QUIZ, YOU WILL ALSO BE REQUIRED TO LIST THE SIX STRONG ACIDS AND ASKED WRITE THE FORMULAS AND NAMES OF ACIDS AND BASES (WE WILL LEARN THAT TODAY)

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3 PROPERTIES OF ACIDS AND BASES ACIDS TASTE SOUR HAVE PH VALUES OF LESS THAN 7 TYPICALLY HAVE A HYDROGEN IN FRONT OF THE FORMULA OR A COOH GROUP (CARBOXYLIC ACIDS) BASES REFERRED TO AS ALKALI TASTE BITTER AND FEEL SLIPPERY HAVE PH VALUES OF GREATER THAN 7 TEND OF HAVE A HYDROXIDE (OH - ) AT THE BACK OF THE FORMULA

4 NAMING ACIDS BINARY ACIDS-CONTAINS ONLY 2 ELEMENTS HYDROGEN AND SOMETHING ELSE NAMING RULES: 1. BEGINS WITH PREFIX HYDRO- 2. ROOT NAME OF THE 2 ND ELEMENT 3. ENDS WITH SUFFIX –IC EXAMPLE: HF HYDROFLUORIC ACID YOU NAME: HCL, HI, H 2 S HYDROCHLORIC ACID, HYDRIODIC ACID, HYDROSULFURIC ACID

5 NAMING ACIDS BE ABLE TO WRITE THE FORMULA GIVEN THE NAME OF A BINARY ACID. EXAMPLE: HYDROBROMIC ACID

6 NAMING ACIDS OXYACID-COMPOUND OF HYDROGEN, OXYGEN, AND A 3 RD ELEMENT (USUALLY NONMETAL) USUALLY 1+ HYDROGENS AND A POLYATOMIC ANION

7 NAMING ACIDS WHEN NAMING ACIDS INVOLVING A POLYATOMIC ION, IF THE ENDING… IS “ATE” THE ACID IS NAMED WITH AN “IC” IS “ITE” THE ACID IS NAMED WITH AN “OUS” EXAMPLE: H 3 PO 4 -PHOSPHORIC ACID EXAMPLE: H 3 PO 3 -PHOSPHOROUS ACID

8 NAMING ACIDS BE ABLE TO WRITE THE FORMULA OF AN OXYACID, GIVEN THE NAME EXAMPLES: NITRIC ACID SULFUROUS ACID ( HINT: THE MAJORITY OF THE TIME, ACIDS START WITH AN “H”, USE THE CRISSCROSS METHOD AND CROSS CHARGES DOWN FROM THE “H” AND THE POLYATOMIC ION”)

9 4/29 PRE-AP PICK UP THE LAB FROM THE SIDE TABLE TAKE OUT A CLEAN PIECE OF PAPER. WE WILL REVIEW HOW TO NAME ACIDS AND THEN YOU WILL PERFORM A LAB TO DETERMINE WHETHER CERTAIN SUBSTANCES ARE AN ACID OR A BASE. HW: STUDY YOUR SOLUBILITY RULES, MEMORIZE THE SIX STRONG ACIDS, AND MAKE SURE YOU CAN NAME AN ACID GIVEN THE FORMULA (NEED TO KNOW POLYATOMICS)

10 EXAMPLES OF STRONG ACIDS~HAVE TO MEMORIZE FOR AP EXAM HCLO 4 PERCHLORIC ACID HIHYDROIODIC ACID HBRHYDROBROMIC ACID HCLHYDROCHLORIC ACID HNO 3 NITRIC ACID H 2 SO 4 SULFURIC ACID (DIPROTIC)

11 5/2 PRE-AP TODAY YOU WILL NEED: TO CLEAR YOUR DESK AS SOON AS YOU WALK IN YOU WILL TAKE A QUIZ OVER NAMING ACIDS, STRONG ACIDS, AND MEMORIZATION OF SOLUBILITY RULES. AFTER THE QUIZ, WE WILL GO OVER ONE OF THE THEORIES YOU NEED TO KNOW FOR ACIDS AND BASES. (IF TIME PERMITS, WE WILL COVER BOTH THEORIES). I WILL NOT SEE BOTH 4 TH AND 6 TH AGAIN UNTIL THURSDAY, WE WILL USE THAT DAY TO TRY AND FINISH THE REST OF THIS UNIT. YOU WILL TEST OVER ACIDS AND BASES NEXT WEEK.

12 NAMING BASES: YOU ARE REQUIRED TO NAME AND THE FORMULA OF A BASE THAT ENDS WITH AN OH-. YOU HAVE ALREADY LEARNED TO NAME THESE COMPOUNDS. QUICK REVIEW: NAME THE FOLLOWING: MG(OH) 2, CU(OH) 2, CUOH, KOH WRITE THE FORMULA FOR THE FOLLOWING: CALCIUM HYDROXIDE, LITHIUM HYDROXIDE, IRON (II) HYDROXIDE

13 COMMONLY USED ACIDS SULFURIC ACID MOST COMMONLY PRODUCED INDUSTRIAL CHEMICAL IN WORLD USED IN CAR BATTERIES NITRIC ACID USED IN MAKING EXPLOSIVES, RUBBER, AND PLASTICS PHOSPHORIC ACID ALONG WITH NITROGEN AND POTASSIUM, PHOSPHORUS IS AN ESSENTIAL ELEMENT FOR PLANTS AND ANIMAL. THE MAJORITY OF PHOSPHORIC ACID PRODUCED IN USED IN FERTILIZERS AND ANIMAL FEED. DILUTED SOLNS USED AS FLAVORING AGENT. HYDROCHLORIC ACID STOMACH ACID USED TO REMOVE IMPURITIES FROM IRON AND STEEL, FOR GENERAL CLEANING, AND TO PRODUCE OTHER CHEMICALS. ACETIC ACID USED IN SYNTHESIZING CHEMICALS USED IN THE MANUFACTURE OF PLASTICS AND AS A FUNGICIDE. A COMPONENT OF VINEGAR-WHITE VINEGAR IS 4-8% ACETIC ACID

14 NAMING BASES MOST OF THE BASES YOU WILL SEE IN THIS CLASS END WITH A HYDROXIDE ION EXAMPLES: MG(OH) 2 NAOH THEY ARE NAMED THE SAME WAY AS NAMING AN IONIC COMPOUND

15 EXAMPLES OF STRONG BASES NAOHSODIUM HYDROXIDE KOHPOTASSIUM HYDROXIDE BA(OH) 2 BARIUM HYDROXIDE *ANY GROUP 1 AND GROUP 2 METAL ATTACHED TO AN OH- ION ARE CONSIDERED STRONG EXCEPT MAGNESIUM AND BERYLIUM.

16 EXAMPLES OF WEAK BASES NH 3 AMMONIA CH 3 NH 2 METHYLAMINE C 5 H 5 NPYRIDINE

17 THEORIES OF ACIDS AND BASES TWO DIFFERENT THEORIES THAT DESCRIBE WHAT DEFINES AN ACID AND A BASE: ARRHENIUS THEORY BRONSTED-LOWRY

18 ARRHENIUS THEORY ARRHENIUS CONCEPT- ACIDS PRODUCE HYDROGEN IONS IN AQUEOUS SOLUTION WHILE BASES PRODUCE HYDROXIDE IONS.

19 ARRHENIUS ACIDS & BASES ARRHENIUS ACID-A CHEMICAL COMPOUND THAT INCREASES THE CONCENTRATION OF HYDROGEN IONS, H +, IN SOLUTION. STRONG ACIDS DISSOCIATE COMPLETELY AND WEAK ACIDS ONLY PARTIALLY DISSOCIATE. ARRHENIUS BASE-A CHEMICAL COMPOUND THAT INCREASES THE CONCENTRATION OF HYDROXIDE IONS, OH -, IN SOLUTION. WEAK BASES-DO NOT IONIZE COMPLETELY IN WATER.

20 IMPORTANT TO REMEMBER: YOU NEED TO KNOW YOUR 6 STRONG ACIDS. ASSUME EVERY OTHER ACID IS WEAK YOU ALSO NEED TO KNOW WHICH BASES CONTAINING A HYDROXIDE GROUP WILL DISSOCIATE (BASED OFF OF SOLUBILITY RULES) IF SOMETHING IONIZES/DISSOCIATES COMPLETELY: USE A SINGLE SIDED ARROW IF SOMETHING IONIZES/DISSOCIATES PARTIALLY: USE A DOUBLE SIDED ARROW (EQUILIBRIUM ARROW)

21 ARRHENIUS EXAMPLES 1. WRITE THE DISSOCIATION FOR THE FOLLOWING ACIDS AND BASES ACCORDING TO THE ARRHENIUS THEORY OF ACIDS AND BASES. A. HYDROCHLORIC ACID B. SODIUM HYDROXIDE C. NITRIC ACID D. CARBONIC ACIDS E. CALCIUM CHLORIDE F. BERYLLIUM HYDROXIDE 2. DRAW A BEAKER CONTAINING: A. HYDROBROMIC ACID B. NITROUS ACID C. MAGNESIUM HYROXIDE D. LITHIUM HYROXIDE

22 PRE-AP 5/5 TURN IN THE ARRHENIUS EXAMPLES FROM MONDAY. PICK UP THE PAPER FROM THE SIDE TABLE WE WILL GO OVER THE SECOND THEORY OF ACIDS AND BASES TODAY AFTER WE REVIEW THE ARRHENIUS THEORY. (REMEMBER THIS IS THE ONE IN WATER, AKA…A SOLUTION) TAKE OUT A PIECE OF PAPER AND SOMETHING TO WRITE WITH. I HAVE ANOTHER ACTIVITY PLANNED FOR YOU TO DO TODAY. WE WILL TALK ABOUT THIS AFTER CLASS STARTS.

23 ARRHENIUS REVIEW 1.WHAT IS AN ARRHENIUS ACID? 2. WHAT IS AN ARRHENIUS BASE? 3. DRAW A BEAKER CONTAINING: A. HYDROFLOURIC ACID B. NITRIC ACID 4. WRITE THE DISSOCIATION FOR THE FOLLOWING ACIDS AND BASES ACCORDING TO THE ARRHENIUS THEORY OF ACIDS AND BASES. A. HYDROPHOSPHORIC ACID B. LITHIUM HYDROXIDE C. SULFURIC ACID D. IRON (III) HYDROXIDE

24 BRONSTED-LOWRY THEORY OF ACIDS & BASES SOME SUBSTANCES THAT ACT AS ACIDS AND BASES ARE NOT COVERED BY THE ARRHENIUS DEFINITIONS BECAUSE THEY ARE NOT IN AQUEOUS SOLUTION. BRONSTED-LOWRY COVERS ALL ACIDS AND BASE A BRONSTED-LOWRY ACID IS A MOLECULE OR ION THAT IS A PROTON DONOR. A BRONSTED-LOWRY BASE IS A MOLECULE OR ION THAT IS A PROTON ACCEPTOR (HYDROGEN).

25 BRONSTED-LOWRY ACID A BL ACID IS A MOLECULE OR ION THAT IS A PROTON DONOR, MEANING IT GIVES UP ITS IONIZABLE HYDROGEN TO ANOTHER SPECIES IN THE REACTION. HCL + NH 3  CL - + NH 4 + IN THE REACTION ABOVE, HYDROCHLORIC ACID ACTS AS A BL ACID BECAUSE IT DONATES A PROTON TO AMMONIA, NH 3. HCL + H 2 O  CL - + H 3 O + HYDROCHLORIC ACID ALSO ACTS AS A BL ACID IN A REACTION WITH WATER, DONATING A PROTON TO FORM THE HYDRONIUM ION, H 3 O +.

26 BRONSTED-LOWRY BASE A BL BASE IS A MOLECULE OR ION THAT IS A PROTON ACCEPTOR, MEANING IT ACCEPTS THE IONIZED HYDROGEN FROM AN ACID. HCL + NH 3  CL - + NH 4 + IN THE REACTION ABOVE, AMMONIA ACTS AS A BL BASE BECAUSE IT ACCEPTS A PROTON FROM HCL TO FORM AMMONIUM, NH 4 +. HCL + H 2 O  CL - + H 3 O + WHAT IS ACTING AS THE BL BASE IN THIS REACTION?

27 BRONSTED-LOWRY ACID-BASE REACTIONS IN A REACTION BETWEEN A BRONSTED-LOWRY ACID AND A BRONSTED-LOWRY BASE, PROTONS ARE TRANSFERRED FROM ONE REACTANT (THE ACID) TO THE OTHER (THE BASE).

28 BRONSTED-LOWRY ACID-BASE EXAMPLE LABEL EACH REACTANT AND PRODUCT IN THE REACTIONS BELOW AS A PROTON DONOR (BL ACID) OR A PROTON ACCEPTOR (BL BASE). H 2 CO 3 + H 2 O ⇌ HCO 3 - + H 3 O + HF + NH 3  NH 4 + + F - CH 3 NH 2 + H 2 O ⇌ CH 3 NH 3 + + OH - CONSIDER THE FOLLOWING REACTIONS. IDENTIFY THE ARRHENIUS ACIDS AND BASES AND BRONSTED-LOWRY ACID AND BASES IN THESE REACTION AND EXPLAIN. NAOH (S)  NA + (AQ) + OH - (AQ) HF (AQ) + H 2 O (L)  F - (AQ) + H 3 O + (AQ) HCL (AQ) + NH 3(AQ)  NH 4 + (AQ) + CL - (AQ)

29 CONJUGATE ACID-BASE PAIRS SIMILARLY, A BASE ALWAYS ACCEPTS A PROTON FROM AN ACID IN A BL ACID-BASE REACTION. HX + Y ⇌ X - + HY + THE REMAINING ION OR MOLECULE (HY + ) CAN DONATE THAT PROTON IN THE REVERSE REACTION, ACTING AS AN ACID. THIS ACID FORMED BY THE REACTION OF A BL BASE IS KNOWN AS THE CONJUGATE ACID OF THE BASE. HF + H 2 O ⇌ F - + H 3 O + FOR EXAMPLE, H 3 O + IS THE CONJUGATE ACID OF H 2 O.

30 CONJUGATE ACID-BASE PAIRS BL ACID-BASE REACTIONS REACH A STATE OF EQUILIBRIUM, WHERE BOTH THE FORWARD AND REVERSE REACTION OCCUR SIMULTANEOUSLY. THEREFORE, THEY INVOLVE TWO ACID-BASE PAIRS, KNOWN AS CONJUGATE ACID- BASE PAIRS: HF + H 2 O ⇌ F - + H 3 O + ACID + BASE ⇌ CONJUGATE BASE + CONJUGATE ACID IN EVERY CONJUGATE ACID-BASE PAIR, THE ACID HAS ONE MORE PROTON THAN ITS CONJUGATE BASE.

31 CONJUGATE ACID-BASE PAIRS 1. IN THE FOLLOWING REACTIONS, IDENTIFY THE CONJUGATE ACID-BASE PAIRS: HCL + H 2 O  H 3 O + + CL - H 2 O + HCLO 4  CLO 4 - + H 3 O + CH 3 COOH + H 2 O  H 3 O + + CH 3 COO - 2. GIVE THE CONJUGATE ACID OF THE FOLLOWING BL BASES: H 2 O PO 4 3- OH - NH 3 3. GIVE THE CONJUGATE BASE OF THE FOLLOWING BL ACIDS: HCO 3 - H 2 O H 2 SO 4

32 AMPHOTERIC COMPOUNDS NOTICE THAT WATER CAN ACT AS EITHER A BL ACID OR BASE: WATER ACTING AS A BASE IN REACTION WITH HCL: HCL + H 2 O  H 3 O + + CL - WATER ACTING AS AN ACID IN REACTION WITH CO 3 2- : CO 3 2- + H 2 O  HCO 3 - + OH - COMPOUNDS THAT CAN ACT AS EITHER AN ACID OR A BASE ARE SAID TO BE AMPHOTERIC. WHETHER AN AMPHOTERIC COMPOUND WILL ACT AS AN ACID OR A BASE IN A REACTION DEPENDS ON THE CONDITIONS OF THE REACTION.

33 5/12 PRE-AP PICK UP THE PAPERS FROM THE SIDE TABLE (THE LAB, THE REVIEW, AND THE LAB REPORT RUBRIC) TAKE OUT THE CALCULATIONS HW YOU RECEIVED TUESDAY. WE WILL CALCULATE A FEW MORE OF THOSE PROBLEMS BEFORE WE MOVE ON) YOU WILL NEED A CALCULATOR FOR THE FIRST PART OF THE PERIOD THE SECOND HALF OF THE PERIOD, YOU WILL PERFORM A TITRATION LAB (THIS IS A SUMMATIVE GRADE AND WILL BE DUE THURSDAY, MAY 19 TH ). YOUR TEST HAS BEEN MOVED TO MONDAY. YOU WILL RECEIVE THE REVIEW TODAY. IT IS DUE ON MONDAY. HW: FINISH THE PH AND POH CALCULATION PAPER.

34 REVIEW: 1. WATER CAN ACT AS AN ACID OR A BASE. WHAT IS THE TERM FOR THIS TYPE OF BEHAVIOR? 2. CALCULATE THE PH OF A SOLUTION THAT HAS [H+]=1 X 10 -9 3. CALCULATE THE [OH-] OF A SOLUTION WITH A POH=6.20. 4. CALCULATE THE PH OF A SOLUTION WITH POH=8.20 5. IF [H+]=1 X 10 -5, WHAT IS THE POH VALUE? 6. IF PH=5, WHAT IS [OH-]?

35 Acid-Base Titrations

36 Titrations Curves  In an acid/base titration, the titrant (commonly a base) is added to a solution of unknown concentration until the substance being analyzed is just consumed (hits its equivalence point).  Titrant-solution of known concentration (in buret)  titration curve -plot of pH as a function of the amount of titrant added.  Equivalence point- the point in which chemically equivalent quantities of acid and base have been mixed. Can be found by using an indicator.

37 http://www.youtube.com/watch?v=yirkozUyG74 Titration Curves

38 There are three main types of acid/base titrations. We will briefly look at an example of each one and discuss how to recognize the type of titration curve.

39 1.Strong Acid-Strong Base  Simple reaction H + + OH -  H 2 O  The pH is easy to calculate because all reactions go to completion.  At the equivalence point, the solution is neutral.

40 2.Weak Acid-Strong Base  At the equivalence point, a basic salt is present and the pH will be greater than 7. After the equivalence point, the strong base will be the dominant species.

41 3. Weak Base-Strong Acid  At the equivalence point, an acidic salt is present and the pH is below 7. After the equivalence point, the strong acid is the dominant species.

42 Acid-Base Indicators  Equivalence point/endpoint - the point in a titration where the indicator changes color  A very common indicator, phenolphthalein, is colorless in its acid form and pink in its base form. It changes color in the range of pH 8-10.

43 ACID-BASE REACTIONS

44 NEUTRALIZATION REACTION WHEN ACIDIC AND BASIC COMPOUNDS REACT WITH EACH OTHER, EACH NEUTRALIZES THE OTHER. FOR EXAMPLE: ANTACIDS, WHICH ARE BASIC, HELP EASE INDIGESTION BY REACTING WITH & NEUTRALIZING EXCESS STOMACH ACID. SODIUM BICARBONATE & TARTARIC ACID ARE 2 COMPONENTS IN BAKING POWDER. WHEN PUT INTO SOLUTION, THE TWO COMPOUNDS PRODUCE CO 2 GAS WHICH CAUSES FOODS SUCH AS BISCUITS TO RISE.

45 NEUTRALIZATION REACTIONS IN AQUEOUS SOLUTIONS WHEN A STRONG ACID AND A STRONG BASE IN AN AQUEOUS SOLUTION UNDERGO A NEUTRALIZATION REACTION, 2 PRODUCTS ARE FORMED: A SALT-AN IONIC COMPOUND COMPOSED OF A CATION FROM A BASE AND AN ANION FROM AN ACID, AND WATER.

46 EXAMPLE WRITE AN EQUATION TO REPRESENT THE NEUTRALIZATION REACTION THAT OCCURS WHEN AQUEOUS SOLUTIONS OF HYDROCHLORIC ACID AND SODIUM HYDROXIDE ARE MIXED. WRITE THE NET IONIC EQUATION

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48 AQUEOUS SOLUTIONS & THE CONCEPT OF PH

49 pH Scale Examples: 49

50 Acid – Base Concentrations pH = 3 pH = 7 pH = 11 OH - H3O+H3O+ H3O+H3O+ H3O+H3O+ [H 3 O + ] = [OH - ] [H 3 O + ] > [OH - ] [H 3 O + ] < [OH - ] acidic solution neutral solution basic solution concentration (moles/L) 10 -14 10 -7 10 -1 Timberlake, Chemistry 7 th Edition, page 332

51 Hydronium Concentrations with pH/pOH

52 FORMULAS PH=-LOG[H+] POH=-LOG[OH-]LOG PH + POH = 14 KW= [H+][OH-]=1 X 10 -14[ H 3 O + ]  [H 3 OH - ]=10 -POH

53 pH and [H+] calculations 1. Calculate the [H+] for: pH=11 pH=11 pH=2.5 pH=2.5 2. Calculate the pH for the following: [H+]= 1 X 10 -5 [H+]= 3.8 X 10 -10

54 pOH and [OH-] calculations 1. Calculate the [OH-] for: pOH=11 pOH=11 pOH=3.8 pOH=3.8 2. Calculate the pOH for the following: [OH-]= 1 X 10 -11 [OH-]= 3.8 X 10 -4

55 pH and pOH 1. Calculate the pOH values of the following: 1. Calculate the pOH values of the following: pH=5.0 pH=5.0 pH=11.25 pH=11.25 2. Calculate the pH value of the following: 2. Calculate the pH value of the following: pOH=11.2 pOH=11.2 pOH=2.53 pOH=2.53

56 More difficult examples: 1. If the hydrogen ion concentration is 1 x 10 -6, what is the the pOH value? Is this an acid or a base? 1. If the hydrogen ion concentration is 1 x 10 -6, what is the the pOH value? Is this an acid or a base? 2. If the pH is 4, what is the hydrogen ion concentration? 2. If the pH is 4, what is the hydrogen ion concentration?

57 Even more examples: (these will make you use your brain) DETERMINE THE HYDRONIUM & HYDROXIDE ION CONCENTRATIONS IN A SOLUTION THAT IS 1 X 10 -4 M HCL. ACIDIC OR BASIC?

58 Even more examples: (these will make you use your brain) DETERMINE THE HYDROGEN ION & HYDROXIDE ION CONCENTRATIONS IN A SOLUTION THAT IS 1 X 10 -4 M CA(OH) 2. ACIDIC OR BASIC?


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