Acids and Bases. Acids Definition : latin meaning sour “Acidus” Lots of acids –Dangerous Nitric Acid, Sulfuric Acid –Essential Ascorbic Acid –Dietary.

Slides:



Advertisements
Similar presentations
Acids Bases and pH Review
Advertisements

Sec. 18.1: Acids & Bases: An Introduction
ACIDS AND BASES
Chapter 14 Acids and Bases 2006, Prentice hall.
Monday, May 2 nd : “A” Day Agenda  Begin chapter 15: Acids & Bases  15.1: “What Are Acids & Bases?” Strong acid, weak acid, strong base, weak base,
Acids bases & salts.
ACIDS AND BASES.
Properties and Theories
ACIDS and BASES. Why ‘acids and bases’? Scientists like to classify things and donating them as acids or bases is one way to do that. If a solution is.
Chapter 14: Acids and Bases and pH
11 IB Topic 8: Acids & Bases 8.1 Theories of Acids & Bases 8.1.1Define acids and bases according to the Brǿnsted- Lowry and Lewis theories Deduce.
 It shouldn't be hard for you to name several common acids, but you might find that listing bases is just a little more difficult.  Here's a partial.
Mullis Acids, Bases and Salts Acids give up hydrogen ions (H + ) in a water solution. Bases give up hydroxide ions (OH - ) in a water solution.
Acids, Bases and Salts Acids give up hydrogen ions (H+) in a water solution. Bases give up hydroxide ions (OH-) in a water solution. Mullis.
Acids & Bases Acids Arrhenius Model Produce hydrogen ions aqueous solution. HCl  H + (aq) + Cl - (aq) Acids you SHOULD know: Acids you SHOULD know:
Acids and Bases. Acids are substances that turn blue litmus red, and usually react with metals such as zinc, releasing hydrogen. Examples: hydrochloric.
6.1 – Introduction to Acids and Bases Unit 6 – Acids and Bases.
Acids and Bases
Friday, April 25 th : “A” Day Monday, April 28 th : “B” Day Agenda  Hand back/go over Ch. 14 Tests  Begin chapter 15: Acids & Bases  15.1: “What.
Chapter 18 “Acids, Bases and Salts”
11 IB Topic 8: Acids & Bases 8.1 Theories of Acids & Bases 8.1.1Define acids and bases according to the Brǿnsted- Lowry and Lewis theories Deduce.
Look at some examples, and see if you can figure out what an acid is… HCl (Hydrochloric acid) HNO 3 (Nitric acid) H 2 SO 4 (Sulfuric acid) H 3 PO 4.
THE CHEMISTRY OF ACIDS AND BASES. ACID AND BASES.
What are Acids and Bases ? There are three main theories to describe what acids and bases are In general each theory widens what chemical reactions can.
There are several ways to define acids and bases: Arrhenius ( narrowest/most common definition ) –a–acids – produce H + ions in water –b–bases – produce.
Pick up the PPT notes and the practice paper off the front demo table. PAP CHEMISTRY.
Chapter 16 Acids and Bases Defining Acids and Bases Since the 17 th century, chemists have known about acids and bases… however, it took a while.
Acids and Bases. Common household acids Citric acid Ethanoic acid Lactic acid Stearic acid Acetylsailicylic Acid.
Chapter 15 Acids and Bases. Acids Vocabulary – Hydrogen ion = H +1 = Proton General Properties of Acids: Acids have a sour taste (ex – citrus fruits,
Chapter 15 Acids and Bases. Acids Vocabulary – Hydrogen ion = H +1 = Proton General Properties of Acids: Acids have a sour taste (ex – citrus fruits,
Unit 18 Acids and Bases. I. Defining Acids & Bases A. Properties Acids Bases 1. Taste sour bitter (not in lab) ex: Citrus ex: soap fruits, yogurt vinegar.
ACIDS AND BASES Properties  electrolytes  turn litmus red  sour taste  react with metals to form H 2 gas  slippery feel  turn.
Acids and bases.
Acids & Bases Chpt. 12. When we think of acids and bases we tend to think of chemistry lab acids and bases like But we are surrounded by acids and bases.
Acids and Bases Unit 12. Properties of an Acid  Sour taste  Turns litmus paper red (and responds uniquely to other indicators)  Reacts with:  Hydroxide.
Ch 14.1 Properties of Acids and Bases. Acids  Are sour to taste  React with bases to produce salts and water.  React with metals and release H 2 gas.
Chapter 20 Acids and Bases Describing Acids and Bases Hydrogen Ions and Acidity Acid-Base Theories Strengths of Acids and Bases.
1 Acids, Bases and PH. 2 Some Properties of Acids þ Produce H + (as H 3 O + ) ions in water (the hydronium ion is a hydrogen ion attached to a water molecule)
1 The Chemistry of Acids and Bases Chapter Some Properties of Acids þ Produce H + ions in water þ Taste sour þ Corrode metals þ Electrolytes þ React.
ACIDS, BASES & SALTS The Arrhenius Theory of Acids and Bases.
Acids and Bases. Acids from the Latin word acere  “ sharp ” or “ sour ” taste sour (but you wouldn ’ t taste an acid to see) change litmus paper red.
Chapter 15 Acids and Bases Examples of acids: Vinegar Lemon Juice Soft Drink Battery Acid Stomach Acid Apple Juice Black Tea.
Acids & Bases. Properties ACIDS: Sour taste Conduct electricity React with active metals to form H gas React with carbonate compounds to form CO2 gas.
Acids, Bases, and Salts Chapter 18. Properties of Acids and Bases When dissolved in distilled water, they look the same Taste –Acid developed from the.
1 - SCH3U1 - Acids and Bases Sections Learning Goals 1.What is Arrhenius's definition of an acid? A base? 2.What is the Brønsted-Lowry definition.
Acid and Bases: An Introduction. Properties of Acids 1. Sour taste 2. Can produce H + (hydrogen) ions (protons) 3. Change the color of litmus from blue.
Water Solutions of Acids Universal Indicator is yellow Turn phenolphthalein colorless Turn litmus paper red React with metals to give off hydrogen gas.
Pages Ch. 14 – Acids, Bases, & Salts. Properties  Taste Sour.  Can sting skin if open (cut).  React with metals to produce H 2 gas.  Disassociate.
Mullis Acids, Bases and Salts Acids give up hydrogen ions (H + ) in a water solution. Bases give up hydroxide ions (OH - ) in a water solution.
Acids, Bases, & Salts. Properties  Taste Sour.  Can sting skin if open (cut).  React with metals to produce H 2 gas.  Disassociate in water to produce.
1 Acids and Bases Operational definitions are based on observed properties. Compounds can be Classified as acid or base by observing these sets of properties.
“Acids, Bases, and Salts”
Taste sour Taste sour Form solution that conduct electricity Form solution that conduct electricity React with metals React with metals Turn blue litmus.
When we think of acids and bases we tend to think of chemistry lab acids and bases like But we are surrounded by acids and bases in the world. Most of.
1 Dr. Marwa Eid. 3 4  An acid is a solution that has an excess of H + (hydrogen ion).  The more H + ions, the more acidic the solution.
Acid-Base Theories The “Boyz”. Acid and Base Theories2 Arrhenius Theory of Acids Acid: molecular substances that breaks-ups in aqueous solution into H+
Acids & Bases Chapter 9. Arrhenius Acid DEFINITION Any substance that releases hydrogen ions in water. Any substance that releases hydrogen ions in water.EQUATION:
Acids and Bases – Acid Strength and K a.
Acid and base Iman AlAjeyan. Acid-Base Theory Acids in water solutions show certain properties. They taste sour and turn litmus paper red. They react.
Ch 9: Acids, Bases and Salts Suggested Problems: 2, 6, 10, 12, 28-44, 82, , Bonus: 118.
Acids and Bases Definitions and Properties. Acidic or Basic?
Acids and Bases Chemistry Chapter 15 Acids and Bases.
Ch 14.1 Properties of Acids and Bases. Acids  Are sour to taste  React with bases to produce salt and water.  React with metals and release H 2 gas.
Acids and Bases.
Acids and Bases Chapter 15 & 16.
Bronsted/Lowry Theory of Acids and Bases
The Chemistry of Acids and Bases
Acids and Bases.
Acids and Bases Chapter 12.
Acid / Base Theories Peter Jackson.
Presentation transcript:

Acids and Bases

Acids Definition : latin meaning sour “Acidus” Lots of acids –Dangerous Nitric Acid, Sulfuric Acid –Essential Ascorbic Acid –Dietary Acetic Acid (ethanoic acid) (vinegar), Citric Acid, Carbonic Acid –Odd Stearic Acid, Benzoic Acid

info Turns blue Litmus paper Red React with metals to produce hydrogen gas H 2 SO 4 + ZnZnSO 4 + H 2 React with Carbonates to produce CO 2

Arrhenius Theory An acid is a substance that dissociates in water to produce H + ions –Svante Arrhenius (nobel prize 1903)

Add HCl to water and we get H + ions and Chlorine Nitric and Sulfuric acid behave the same HClH + +Cl HNO 3 H + +NO 3 H 2 SO 4 2H + +SO 4 2-

When we add a solution of Hydrogen chloride to water we call it Hydrochl o ric acid Mono basic: HClH + +Cl Di Basic H 2 SO 4 2H + +SO 4 2- Tri Basic H 3 PO 4 3H + +PO 4 3- Dependant on the number of hydrogen ions donated

Strong and weak acids Sulfuric and nitric are strong as they dissociate fully in water but acetic acid is weak as it only partially dissociates

Hydronium Ion The H + ion....just a proton Cannot exist independently in solution so the Hydronium ion is born The oxygen atom allows an electron to form a dative covalent bond with the hydrogen atom

Hydrogen ion reacts with water to form Hydronium Ion H 3 O + O HXHX H+H+ XHXH.... HXHX H+H+ XHXH.. O.. +

Hydronium Ion For accuracy we should use HA +H 2 OH 3 O + + A - HCl +H 2 OH 3 O + + Cl - Many chemists simply say the hydrogen ion

Importance of water If we add pure Hydrogen Chloride or acetic acid into a solvent like benzene (no water) we do not get either H + or Hydronium ion formation and blue litmus paper stays blue Shows that Hydrogen Chloride or acetic acid is only acid when water is present

Bases Behave in the opposite manner to acids Turn Red litmus paper blue Example: –Sodium Hydroxide (NaOH) –Magnesium Hydroxide ([Mg(OH) 2 ]) –Calcium Hydroxide ([Ca(OH) 2 ])

Info Many bases have a soapy feel Used as degreasers in household detergents Act by converting the oil into soap which washes away more easily

Arrhenius Theory A base is a substance that dissociates in water to produce OH - ions The OH - ion is called the hydroxide ion When added to water it dissociates completely into Sodium ions and hydroxide ions NaOH Na + + OH -

Arrhenius Theory Similarly for Magnesium Hydroxide and Calcium Hydroxide [Mg(OH) 2 ]Mg OH - [Ca(OH) 2 ]Ca OH -

Strong and Weak bases Strong bases include Sodium Hydroxide because they dissociate almost completely in water but....Magnesium Hydroxide and Calcium Hydroxide do not and are referred to as weak bases

A number of flaws to the Arrhenius Theory Hydronium ions are present not bare hydrogen ions Arrhenius theory limited to aqueous solutions and not all acid base reactions are water based NH 3 +HClNH 4 Cl Baseacidammonium chloride

Brønsted -Lowry Update needed to reflect more accurately the reactions that occur 1923 Johannes Bronsted (Danish) & Thomas Lowry (English) – working independently came up with the same theory

Brønsted -Lowry Definition of an Acid –An acid is a proton donor Definition of a base –A Base is a proton acceptor

Detail HCl +H 2 OH 3 O + + Cl - Acidbase Donatesaccepts a protona proton Therefore these obey the B/L definition

Ammonia Gas NH 3 +H 2 ONH OH - baseacid accepts Donates a protona proton Therefore these obey the B/L definition

What to learn Water can act as an acid or a base - amphoteric

Can be applied to non aqueous reactions HCl+ NH 3 NH 4 + +Cl - Acidbase Brønsted –Lowry broadens the definition of what can act as an acid or a base

Homework Questions 12.1 in textbook and 12.1 in workbook

Conjugate acid-base pairs Add acetic acid (ethanoic acid) to water CH 3 COOH+ H 2 OCH 3 COO - + H 3 O The reaction works in both directions

Conjugate acid-base pairs Add acetic acid (ethanoic acid) to water CH 3 COOH+ H 2 OCH 3 COO - + H 3 O Donatesaccepts A protona proton

Conjugate acid-base pairs Add acetic acid (ethanoic acid) to water CH 3 COO - + H 3 O CH 3 COOH+ H 2 O AcceptsDonates A protona proton The water is behaving like an acid

Conjugate acid-base pairs Add acetic acid (ethanoic acid) to water CH 3 COOH+ H 2 OCH 3 COO - + H 3 O The reaction works in both directions so we call each conjugate pairs CH 3 COOH is a conjugate acid of CH 3 COO - CH 3 COO - is a conjugate base of CH 3 COOH

An acid changes into a conjugate base when it donates a proton CH 3 COOHCH 3 COO - H + acidConjugate proton base A base changes into a conjugate acid when it accepts a proton CH 3 COO - H + CH 3 COOH baseproton conjugate acid

Every acid has a conjugate base and every base has a conjugate acid... We call this an conjugate acid - base pair A conjugate acid – base pair is any pair consisting of an acid and a base which differs by one proton

Important The definition says that the pair must involve a single proton so...the conjugate pair of H 2 SO 4 HSO 4 -

Example What is the conjugate acid and the conjugate base of HC 2 O 4 - To change into its conjugate the base must accept a proton...so HC 2 O 4 - +H + H 2 C 2 O 4 HC 2 O 4 - +H + H 2 C 2 O 4 baseconjugate acid

Example What is the conjugate acid and the conjugate base of HC 2 O 4 - To change into its conjugate the acid must donate a proton...so HC 2 O 4 - C 2 O H + HC 2 O 4 - C 2 O H + Acidconjugate base

Tell me Which is the acid and which is the base HNO 3 + H 2 F 2 H 2 NO 3 + HF 2 Also mark out the pairs

HNO 3 + H 2 F 2 H 2 NO 3 + HF 2 Conjugate acid-base pair Acid Base

Neutralisation Neutralisation is the reaction between an acid and a base to form salt and water

Neutralisation Acids and base in the correct proportions cancel each other out This means they lose their characterisitics,the acid is no longer behaving like and acid and vice versa The resulting solution has a neutral effect on litmus paper

example HCl + NaOHNaCl+ H 2 O The word salt simply refers to the fact that the hydrogen in the acid is replaced by a metal or ammonium ion

What’s Happening? HCl + NaOHNaCl+ H 2 O In soln: H + + Cl - + Na + + OH - Na + + Cl - = H 2 O Lets ignore the spectator ions

H + + Cl - + Na + + OH - Na + + Cl - = H 2 O The hydrogen (hydronium) ions from the acid are reacting with the hydroxide ions from the base to form water which results in a neutral solution

Everyday examples Stomach HCL neutralised by NaHCO 3 –In other words...by an antacid (bioSodol) containing sodium hydrogencarbonate HCl + NaHCO 3 NaCl + H 2 O + CO 2 Another example (Maalox) 2HCl + Mg(OH) 2 MgCl + H 2 O

Everyday examples Calcium Oxide (lime) spread on soil to neutralize the acid conditions CaO + H 2 O Ca(OH) 2 Lime + waterCalcium Hydroxide Calcium Hydroxide can neutralize acidity as follows Ca(OH) 2 + H 2 SO 4 CaSO 4 + 2H 2 O Calcium hydroxide plus Sulfuric Acid becomes Calcium Sulfate and Water

Everyday examples Limestone added to lake water to neuralise the effects of acid rain CaCO 3 + H 2 SO 4 CaSO 4 + 2H 2 O + CO 2 Calcium carbonate plus Sulfuric Acid becomes Calcium Sulfate and Water and Carbon Dioxide

Homework Questions 12.2 – 12.6 in textbook and 12.2 – 12.4 in workbook