Pg 569 - 581.  Amphoteric substance: can act as an acid or as a base ◦ Water is the most common amphoteric substance  Self-ionization of water: H 2.

Slides:

Advertisements

Similar presentations

Ways to measure Acidity/Basicity What is pH? What is pOH?

Advertisements

Ch.15: Acid-Base and pH Part 1.

How is pH defined? The pH of a solution is the negative logarithm of the hydrogen-ion concentration. The pH may be represented mathematically, using the.

Acid / Base Equilibria A Practical Application of the Principles of Equilibrium.

Chapter 10 Acids and Bases

Calculating pH and pOH. pH pH = - log [H + ] [H + ] = the hydrogen ion concentration pH: “potential of hydrogen” - A way of expressing the hydrogen ion.

Chemistry Notes: pH Calculations Chemistry

pH scale Measures the amount of H + in a solution. Scale used to measure whether a substance is an acid or a base. Lower numbers are acids. Higher numbers.

pH scale Logarithmic scale expressing the H + concentration, [H + ]. If the pH changes by a factor of 1, the [H + ] changes by a factor of 10. pH =

Unit 8: Acids & Bases PART 2: pH, pOH & pK w. The pH Scale pH is a value chemists use to give a measure of the acidity or alkalinity of a solution. Used.

Hydrogen Ions and Acidity. Hydrogen Ions from Water Water is highly polar – what does that mean? Water particles are in continuous motion If they possess.

We can perform calculations involving pH, pOH, and other quantities for pure water when we’re not at 25°C. We’ll do one example here. Calculations Involving.

Chapter 19 More about ACID-BASES. Self-Ionization of Water Two water molecules produce a hydronium ion & a hydroxide ion by the transfer of a proton.

Ch. 18: Acids & Bases Sec. 18.3: What is pH?. Objectives n Explain the meaning of pH and pOH. n Relate pH and pOH to the ion product constant for water.

What is pH?. Ion Product Constant for Water  H 2 O(l)  H + (aq) + OH - (aq)  Keq = Kw = [H + ] x [OH - ]  The ion product constant for water (Kw)

How is pH defined? The pH of a solution is the negative logarithm of the hydrogen-ion concentration. The pH may be represented mathematically, using the.

14.3 pH Scale 14.4 pH of Strong Acids

Note Guide 10-2 Hydrogen Ions from water (water molecule highly polar) --A water molecule that loses a hydrogen ion becomes a negatively charged hydroxide.

Acid-Base Equilibrium According to Arrhenius theory, substances were acids if they contained hydrogen ion (H + ), and bases if they contained hydroxide.

Kw, pH, and pOH calculations

Review 1: Written the conjugate base and acid for the following acids and bases.

18-3 Hydrogen Ions and pH  The self-ionization of water is …. HOH ↔ H+ + OH-  Ion Product Constant for Water Kw =[H+][OH-]=1.0 x 10-14M2  Use this to.

Let’s take a look at water  2H 2 O  H 3 O + + OH -  [H 3 O + ][OH - ]= 1x M 2  [H 3 O + ]= 1x10 -7 M  [OH - ]= 1x10 -7 M  K w = 1x M.

PH. The Ion product constant for water H 2 O (l) + H 2 O (l)  H 3 O + (aq) + OH − (aq) Dissociation of water is an equilibrium, and since liquid water.

Ch. 15 & 16 - Acids & Bases II. pH (p ) C. Johannesson.

PH ( power of hydronium ion). The pH scale is a way of expressing the strength of acids and bases. Instead of using very small numbers, we just use the.

NOTES: 19.2 – Hydrogen Ions & Acidity (pH and pOH)

C. Johannesson Ch. 15 & 16 - Acids & Bases II. pH (p )

Acids & Bases pH. Ionization of Water H 2 O + H 2 O H 3 O + + OH - K w = [H 3 O + ][OH - ] = 1.0  Kw=ionization constant for H2O.

PH And pOH. Water Water autoionizes H 2 O + H 2 O H 3 O+ + OH- Hydrogen ion concentration determines the acidity of the solution Kc = [H3O+][OH-] ionization.

Friday, March 14, 2008 Turn in Labs Extra Credit Opportunity Review Homework Section 16.1B – Acid Strength Section 16.1C – Water as an Acid and A Base.

Question 1: Name two properties of an acid- Question 2:Name two properties of a base? Academic Chemistry March 20,2012 sour, corrosive, reacts with metals.

Section 16.2 Determining the Acidity of a Solution 1.To understand and determine pH and pOH 2.To learn methods for measuring pH of a solution Objectives.

ION CONCENTRATIONS pH and pOH Calculations.  The pH scale is used to identify a substance as an acid or a base due to the pH value.  This scale is a.

K w, pH, and pOH. IONIZATION OF WATER Water is capable of reacting with itself in an ionization reaction H 2 O (l) + H 2 O (l) ⇌ H 3 O + (aq) + OH - (aq)

Acid-Base Titration and pH l Aqueous Solution and the Concept of pH – Hydronium Ions and Hydroxide Ions – The pH Scale – Calculating Involving pH l Determining.

Power of hydrogen. pH scale logarithmic scale expresses H +1 concentration, [H +1 ] pH = -log[H +1 ]pH = -log[H +1 ] If pH changes by factor of 1, [H.

Strong and Weak Acids and Bases

Acid-Base Titration and pH 1. What ions are associated with acids? Bases? 2.What mathematical operation is the pH scale based on? 3.What is the pH scale?

PH. Ionization of Water  When compounds dissociate/ionize in an aqueous solution, they produce ions - hydronium (H 3 O + ) and hydroxide (OH - )  These.

Acids, Bases, and pH.

Acids and Bases Bundle 4: Water.

The pH Scale Hydronium & Hydroxide Ions (H3O+) (OH–) pH Scale

Self Ionization of Water and the pH Scale

Ch. 19 Acids & Bases II. pH.

Acids and Bases Bundle 4: Water.

Acids and Bases Bundle 4: Water.

Calculations with Acids and Bases

Can you calculate for acids and bases?

Calculating Concentration

Acids & Bases II. pH.

Unit 14 – Acid, Bases, & Salts

Unit 13 – Acid, Bases, & Salts

Calculating Concentration

Ch. 15 & 16 - Acids & Bases II. pH (p ) C. Johannesson.

Calculating pH from the Water Constant

pH Calculations pH = -log[H+] 10-pH = [H+] pOH = -log[OH-]

Unit 13 – Acid, Bases, & Salts

Calculating pH and pOH.

pOH and [OH-] Calculations

Calculating pH (and pOH)

Unit 15 – Acid, Bases, & Salts

Unit 13 – Acid, Bases, & Salts

Unit 14 – Acid, Bases, & Salts

Unit 5- lecture 5 Using the pH scale to characterize acids and bases.

Unit 13 – Acid, Bases, & Salts

Ch. 14 & 15 - Acids & Bases II. pH.

Presentation transcript:

Pg

 Amphoteric substance: can act as an acid or as a base ◦ Water is the most common amphoteric substance  Self-ionization of water: H 2 O(l) + H 2 O(l) H 3 O + (aq) + OH - (aq)

 At 25 o C actual concentrations are: ◦ [H 3 O + ] = [OH - ] = 1.0 x M  The product of the two concentrations is: ◦ [H 3 O + ]*[OH - ] = 1.0 x o C  We call this K w  To simplify the equation, we write H 3 O + as H +  K w = [H + ]*[OH - ] = 1.0 x o C

 Kw = ion-proton constant ◦ In any aqueous solution at 25 o C, no matter what it contains, the product of [H + ] and [OH - ] must ALWAYS equal 1.0 x  What will happen if the concentration of H + increases? If it decreases? ◦ If [H + ] increases, [OH - ] decreases ◦ If [H + ] decreases, [OH - ] increases

1. [H + ] = [OH - ] neutral 2. [H + ] > [OH - ] acidic 3. [H + ] < [OH - ] basic Remember: [H + ]*[OH - ] = 1 x

Calculate [H + ] or [OH - ] as required for each of the following solutions at 25 °C, and state whether the solution is neutral, acidic, or basic. a)1.0 x M OH - b)1.0 x M OH - c)10.0 M H + H+ = 1.0 x M, basic H+ = 1.0 x M, neutral OH- = 1.0 x M, acidic Calculate [H+] in a solution in which [OH-] = 2.0 x M. Is this solution acidic, neutral or basic?  5.0 x M, basic

 pH measures the “power” of the hydrogen ion ◦ “Power” refers to exponent of 10 ◦ Based on the base 10 log scale.  pH = -log[H + ]  If [H + ]= 1.00 x 10 -7, pH = ?  If [H + ]= 1.00 x 10 -2, pH = ?  [H+] = inverse log (-pH)  If pH = 9, [H + ]=?  If a solution has a pH of 2, how much more acidic is it than a solution with a pH of 4?  100 times more acidic!!

Try the following: 1. Find pH if [H + ] = 3.5 x Find pH if [OH - ] = 1.4 x If the pH = 9.4 what is [H + ] ? If the pH = 4.9 what is [OH - ] ? Answers: 1) 2.452) ) 4.0 x ) 7.9 x

 pOH = -log[OH - ]  If pH = 5, What would pOH be?  pH + pOH = 14.00

1. The pOH of a solution is What is the [OH - ] of the solution? What is the [H + ]? 2. The [OH - ] of drain cleaner is 3.2 x M. What is the pOH? The pH? Is it acidic, basic or neutral? 1)2.1 x M and 4.8 x M 2)10.50 and 3.50 = acidic!!