Solutions to Homework Assignment 10 CHM 152 Spring 2002

Size: px
Start display at page:

Download "Solutions to Homework Assignment 10 CHM 152 Spring 2002"

Transcription

1 Solutions to Homework Assignment 10 CHM 152 Spring (a) This is a weak acid problem. Setting up the standard equilibrium table: CH 3 COOH(aq) H + (aq) + CH 3 COO (aq) Initial (M): Equilibrium (M): (0.40 x) +x +x = 2 2 [H ][CH3COO ] x x = [CH3COOH] (0.40 x) 0.40 x = [H + ] = M ph = 2.57 In addition to the acetate ion formed from the ionization of acetic acid, we also have acetate ion formed from the sodium acetate dissolving. CH 3 COONa(aq) CH 3 COO (aq) + Na + (aq) Dissolving 0.20 M sodium acetate initially produces 0.20 M CH 3 COO and 0.20 M Na +. The sodium ions are not involved in any further equilibrium (why?), but the acetate ions must be added to the equilibrium in part (a). CH 3 COOH(aq) H + (aq) + CH 3 COO (aq) Initial (M): Equilibrium (M): (0.40 x) +x ( x) = [H ][CH3COO ] ( x)( x) x(0.20) = [CH3COOH] (0.40 x) 0.40 x = [H + ] = M ph = 4.44 Could you have predicted whether the ph should have increased or decreased after the addition of the sodium acetate to the pure 0.40 M acetic acid in part (a)? An alternate way to work part of this problem is to use the Henderson-Hasselbalch equation. [conjugate base] ph = pk a + log [acid] ph M = log( ) + log 0.40 M = = 4.44

2 16.4 (a) This is a weak base calculation. K b = [NH = 4 ][OH ] ( x)( x) = [NH ] 0.20 x x = M = [OH ] poh = 2.72 ph = NH 4 Cl completely ionizes to give 0.30 M NH 4 + and 0.30 M Cl. NH4 + is the conjugate acid of NH3, and its concentration must be added to the equilibrium from part (a). NH 3 (aq) + H 2 O (l) NH 4 + (aq) + OH (aq) Initial (M): Equilibrium (M): (0.20 x) ( x) x 5 ( x)( x) K b = = (. 020 x) x = [OH ] = M poh = 4.92 ph = ( x) 020. Could you have predicted whether the ph should have increased or decreased after the addition of the ammonium chloride to the pure 0.20 M ammonia in part (a)? You could also use the Henderson-Hasselbalch equation to solve part. Table 15.4 gives the value of K a for the ammonium ion. Using this and the given concentrations with the Henderson- Hasselbalch equation gives: [ ] 10 ph = pk a + log ( ) ph = = 9.07 ( ) ( ) conjugate base = log log 0.20 acid 0.30 Is there any difference in the Henderson-Hasselbalch equation in the cases of a weak acid and its conjugate base and a weak base and its conjugate acid? 16.7 The p in front of pk a means "take the negative log" (Think of the meanings of ph and poh). A smaller pk a value will correspond to a larger K a value and hence a stronger acid. Therefore, the acid with pk a of 5.9 is the stronger acid (a) HCl (hydrochloric acid) is a strong acid. A buffer is a solution containing both a weak acid and a weak base. Therefore, this is not a buffer system. (c) NH 3 (ammonia) is a weak base, and its conjugate acid, NH 4 + is a weak acid. Therefore, this is a buffer system. This solution contains both a weak acid, H 2 PO 4 and its conjugate base, HPO4 2. Therefore, this is a buffer system.

3 (d) HNO 2 (nitrous acid) is a weak acid, and its conjugate base, NO 2 (nitrite ion, the anion of the salt KNO 2 ), is a weak base. Therefore, this is a buffer system. (e) (f) H 2 SO 4 (sulfuric acid) is a strong acid. A buffer is a solution containing both a weak acid and a weak base. Therefore, this is not a buffer system. HCOOH (formic acid) is a weak acid, and its conjugate base, HCOO (formate ion, the anion of the salt HCOOK), is a weak base. Therefore, this is a buffer system (a) This problem is greatly simplified because the concentration of the weak acid (acetic acid) is equal to the concentration of its conjugate base (acetate ion). Let s set up a table of initial concentrations, change in concentrations, and equilibrium concentrations. CH 3 COOH (aq) H + (aq) + CH 3 COO (aq) Initial 2.0 M M Change x +x +x Equilibrium 2.0 M x x 2.0 M + x [H ][CH3COO ] [CH3COOH] + + [H ](2.0 + x) [H ](2.0) (2.0 x) 2.0 [H + ] Taking the log of both sides, p ph Thus, for a buffer system in which the [weak acid] = [weak base], ph = pk a ph = log( ) = 4.74 Similar to part (a), ph = p 4.74 Buffer (a) will be a more effective buffer because the concentrations of acid and base components are ten times higher than those in. Thus, buffer (a) can neutralize 10 times more added acid or base compared to buffer H 2 CO 3 (aq) HCO 3 (aq) + H + (aq) K a1 = pk a1 = 6.38 [HCO 3 ] ph = pk a + lo g [H CO ] 2 3

4 8.00 = log [ HCO3 ] [ HCO 2 3] log [ HCO3 ] = 162. [ HCO 2 3] [ HCO3 ] = 41.7 [ HCO 2 3] [ HCO 2 3] = [ HCO3 ] Step 1: Write the equilibrium that occurs between H 2 PO 4 and HPO4 2. Set up a table relating the initial concentrations, the change in concentration to reach equilibrium, and the equilibrium concentrations. H 2 PO 4 (aq) H + (aq) + HPO4 2 (aq) Initial (M): Equilibrium (M): 0.15 x x x Step 2: Write the ionization constant expression in terms of the equilibrium concentrations. Knowing the value of the equilibrium constant (K a ), solve for x. + 2 [H ][HPO 4 ] [H2PO 4] You can look up the K a value for dihydrogen phosphate in Table 15.5 of your text = ( x)( x) (0.15 x) ( x)(0.10) (0.15) x = [H + ] = M Step 3: Having solved for the [H + ], calculate the ph of the solution. ph = log[h + ] = log( ) = For the first part we use K a for ammonium ion. (Why?) The Henderson Hasselbalch equation is 10 (0.20 M ) ph = log( ) + log (0.20 M = 9.25 ) For the second part, the acid base reaction is NH 3 (g) + H + + (aq) NH 4 (aq)

5 We find the number of moles of HCl added 1 L 0.10 mol HCl 10.0 ml = mol HCl 1000 ml 1 L + The number of moles of NH 3 and NH 4 originally present are 1 L 0.20 mol 65.0 ml = mol 1000 ml 1 L + Using the acid base reaction, we find the number of moles of NH 3 and NH 4 after addition of the HCl. moles NH 3 = ( ) mol = mol NH moles NH 4 = ( ) mol = mol NH4 We find the new ph: (0.012) ph = log = 9.18 (0.014) As calculated in Problem 16.10, the ph of this buffer system is equal to pk a. ph = p log( ) = 4.74 (a) The added NaOH will react completely with the acid component of the buffer, CH 3 COOH. NaOH ionizes completely; therefore, mol of OH are added to the buffer. Step 1: The neutralization reaction is: CH 3 COOH (aq) + OH (aq) CH3COO (aq) + H 2 O (l) Initial (mol) After reaction (mol) Step 2: Now, the acetic acid equilibrium is reestablished. Since the volume of the solution is 1.00 L, we can convert directly from moles to molar concentration. CH 3 COOH (aq) H + (aq) + CH 3 COO (aq) Initial (M) Change (M) x +x +x Equilibrium (M) 0.92 x x x Write the K a expression, then solve for x. [H ][CH3COO ] [CH3COOH] = ( x )( x ) (1.08) x (0.92 x) 0.92 x = [H + ] = M

6 Step 3: Having solved for the [H + ], calculate the ph of the solution. ph = log[h + ] = log( ) = 4.82 The ph of the buffer increased from 4.74 to 4.82 upon addition of mol of strong base. The added acid will react completely with the base component of the buffer, CH 3 COO. HCl ionizes completely; therefore, 0.12 mol of H + ion are added to the buffer Step 1: The neutralization reaction is: CH 3 COO (aq) + H + (aq) CH3COOH (aq) Initial (mol) After reaction (mol) Step 2: Now, the acetic acid equilibrium is reestablished. Since the volume of the solution is 1.00 L, we can convert directly from moles to molar concentration. CH 3 COOH (aq) H + (aq) + CH 3 COO (aq) Initial (M) Change (M) x +x +x Equilibrium (M) 1.12 x x x Write the K a expression, then solve for x. [H ][CH3COO ] [CH3COOH] = ( x )( x ) (0.88) x (1.12 x) 1.12 x = [H + ] = M Step 3: Having solved for the [H + ], calculate the ph of the solution. ph = log[h + ] = log( ) = 4.64 The ph of the buffer decreased from 4.74 to 4.64 upon addition of 0.12 mol of strong acid Recall that to prepare a solution of a desired ph,, we should choose a weak acid with a pk a value close to the desired ph. Calculating the pk a for each acid: For HA, p log( ) = 2.57 For HB, p log( ) = 5.36 For HC, p log( ) = 8.59 The buffer solution with a pk a closest to the desired ph is HC. Thus, HC is the best choice to prepare a buffer solution with ph = 8.60.

Acids and Bases. Chapter 16

Acids and Bases. Chapter 16 Acids and Bases Chapter 16 The Arrhenius Model An acid is any substance that produces hydrogen ions, H +, in an aqueous solution. Example: when hydrogen chloride gas is dissolved in water, the following

More information

Acid-Base (Proton-Transfer) Reactions

Acid-Base (Proton-Transfer) Reactions Acid-Base (Proton-Transfer) Reactions Chapter 17 An example of equilibrium: Acid base chemistry What are acids and bases? Every day descriptions Chemical description of acidic and basic solutions by Arrhenius

More information

4. Acid Base Chemistry

4. Acid Base Chemistry 4. Acid Base Chemistry 4.1. Terminology: 4.1.1. Bronsted / Lowry Acid: "An acid is a substance which can donate a hydrogen ion (H+) or a proton, while a base is a substance that accepts a proton. B + HA

More information

1. Read P. 368-375, P. 382-387 & P. 429-436; P. 375 # 1-11 & P. 389 # 1,7,9,12,15; P. 436 #1, 7, 8, 11

1. Read P. 368-375, P. 382-387 & P. 429-436; P. 375 # 1-11 & P. 389 # 1,7,9,12,15; P. 436 #1, 7, 8, 11 SCH3U- R.H.KING ACADEMY SOLUTION & ACID/BASE WORKSHEET Name: The importance of water - MAKING CONNECTION READING 1. Read P. 368-375, P. 382-387 & P. 429-436; P. 375 # 1-11 & P. 389 # 1,7,9,12,15; P. 436

More information

ACID-BASE REACTIONS/ THE PH CONCEPT.

ACID-BASE REACTIONS/ THE PH CONCEPT. Dr Mike Lyons School of Chemistry Trinity College Dublin. melyons@tcd.ie ACID-BASE REACTIONS/ THE PH CONCEPT. Chemistry Preliminary Course 2011 1 Lecture topics. 2 lectures dealing with some core chemistry

More information

Name: Class: Date: 2 4 (aq)

Name: Class: Date: 2 4 (aq) Name: Class: Date: Unit 4 Practice Test Multiple Choice Identify the choice that best completes the statement or answers the question. 1) The balanced molecular equation for complete neutralization of

More information

1. When the following equation is balanced, the coefficient of Al is. Al (s) + H 2 O (l)? Al(OH) 3 (s) + H 2 (g)

1. When the following equation is balanced, the coefficient of Al is. Al (s) + H 2 O (l)? Al(OH) 3 (s) + H 2 (g) 1. When the following equation is balanced, the coefficient of Al is. Al (s) + H 2 O (l)? Al(OH) (s) + H 2 (g) A) 1 B) 2 C) 4 D) 5 E) Al (s) + H 2 O (l)? Al(OH) (s) + H 2 (g) Al (s) + H 2 O (l)? Al(OH)

More information

Acid-base Equilibria and Calculations

Acid-base Equilibria and Calculations Acid-base Equilibria and Calculations A Chem1 Reference Text Stephen K. Lower Simon Fraser University Contents 1 Proton donor-acceptor equilibria 4 1.1 The ion product of water... 4 1.2 Acid and base strengths...

More information

Acid-base Equilibria and Calculations

Acid-base Equilibria and Calculations Acid-base Equilibria and Calculations A Chem1 Reference Text Stephen K. Lower Simon Fraser University Contents 1 Proton donor-acceptor equilibria 4 1.1 The ion product of water... 4 1.2 Acid and base strengths...

More information

Chapter 8, Acid-base equilibria

Chapter 8, Acid-base equilibria Chapter 8, Acid-base equilibria Road map of acid-base equilibria On first encounter, the study of acid-base equilibria is a little like a strange land with seemingly confusing trails that make passage

More information

Chapter 13 & 14 Practice Exam

Chapter 13 & 14 Practice Exam Name: Class: Date: Chapter 13 & 14 Practice Exam Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Acids generally release H 2 gas when they react with a.

More information

Chemistry 201. Practical aspects of buffers. NC State University. Lecture 15

Chemistry 201. Practical aspects of buffers. NC State University. Lecture 15 Chemistry 201 Lecture 15 Practical aspects of buffers NC State University The everyday ph scale To review what ph means in practice, we consider the ph of everyday substances that we know from experience.

More information

ACIDS AND BASES SAFETY PRECAUTIONS

ACIDS AND BASES SAFETY PRECAUTIONS ACIDS AND BASES Mild acids and bases are used in cooking (their reaction makes biscuits and bread rise). Acids such as those in our stomachs eat away at food or digest it. Strong acids and bases are used

More information

I N V E S T I C E D O R O Z V O J E V Z D Ě L Á V Á N Í CHEMICAL REACTIONS

I N V E S T I C E D O R O Z V O J E V Z D Ě L Á V Á N Í CHEMICAL REACTIONS Chemical reaction = process during which original substances change to new substances, reactants turn to... The bonds of reactants... and new bonds are... The classification of reactions: 1. Classification

More information

Q1: What is the ph Scale? Q6: As acids become more acidic, their ph values

Q1: What is the ph Scale? Q6: As acids become more acidic, their ph values Q1: What is the ph Scale? Q6: As acids become more acidic, their ph values increase or decrease? Q2: The range of values of the ph scale is: Q7: As bases become more alkaline, their ph values increase

More information

Ch 15: Acids and Bases

Ch 15: Acids and Bases Ch 15: Acids and Bases A c i d s a n d B a s e s C h 1 5 P a g e 1 Homework: Read Chapter 15 Work out sample/practice exercises in the sections, Bonus problems: 39, 41, 49, 63, 67, 83, 91, 95, 99, 107,

More information

AP*Chemistry The Chemistry of Acids and Bases

AP*Chemistry The Chemistry of Acids and Bases AP*Chemistry The Chemistry of Acids and Bases "ACID"--Latin word acidus, meaning sour. (lemon) "ALKALI"--Arabic word for the ashes that come from burning certain plants; water solutions feel slippery and

More information

PART I: MULTIPLE CHOICE (30 multiple choice questions. Each multiple choice question is worth 2 points)

PART I: MULTIPLE CHOICE (30 multiple choice questions. Each multiple choice question is worth 2 points) CHEMISTRY 123-07 Midterm #1 Answer key October 14, 2010 Statistics: Average: 74 p (74%); Highest: 97 p (95%); Lowest: 33 p (33%) Number of students performing at or above average: 67 (57%) Number of students

More information

Acid 7 Base. 1. Describe two things hydrochloric acid does in your body system. 2. What does sodium hydrogencarbonate do in your body system?

Acid 7 Base. 1. Describe two things hydrochloric acid does in your body system. 2. What does sodium hydrogencarbonate do in your body system? Acids and Bases acid: a compound that, when dissolved in water, forms a solution with a ph less than 7 base: a compound that, when dissolved in water, forms a solution with a ph greater than 7 ph: the

More information

Summer Holidays Questions

Summer Holidays Questions Summer Holidays Questions Chapter 1 1) Barium hydroxide reacts with hydrochloric acid. The initial concentration of the 1 st solution its 0.1M and the volume is 100ml. The initial concentration of the

More information

W1 WORKSHOP ON STOICHIOMETRY

W1 WORKSHOP ON STOICHIOMETRY INTRODUCTION W1 WORKSHOP ON STOICHIOMETRY These notes and exercises are designed to introduce you to the basic concepts required to understand a chemical formula or equation. Relative atomic masses of

More information

SCH 4C1 Unit 2 Problem Set Questions taken from Frank Mustoe et all, "Chemistry 11", McGraw-Hill Ryerson, 2001

SCH 4C1 Unit 2 Problem Set Questions taken from Frank Mustoe et all, Chemistry 11, McGraw-Hill Ryerson, 2001 SCH 4C1 Unit 2 Problem Set Questions taken from Frank Mustoe et all, "Chemistry 11", McGraw-Hill Ryerson, 2001 1. A small pin contains 0.0178 mol of iron. How many atoms of iron are in the pin? 2. A sample

More information

TITRATION CURVES, INDICATORS, AND ACID DISSOCIATION CONSTANTS

TITRATION CURVES, INDICATORS, AND ACID DISSOCIATION CONSTANTS TITRATION CURVES, INDICATORS, AND ACID DISSOCIATION CONSTANTS Adapted from "Chemistry with Computers" Vernier Software, Portland OR, 1997 INTRODUCTION Titration is the volumetric measurement of a solution

More information

n molarity = M = N.B.: n = litres (solution)

n molarity = M = N.B.: n = litres (solution) 1. CONCENTRATION UNITS A solution is a homogeneous mixture of two or more chemical substances. If we have a solution made from a solid and a liquid, we say that the solid is dissolved in the liquid and

More information

Acids and Bases. Problem Set: Chapter 17 questions 5-7, 9, 11, 13, 18, 43, 67a-d, 71 Chapter 18 questions 5-9, 26, 27a-e, 32

Acids and Bases. Problem Set: Chapter 17 questions 5-7, 9, 11, 13, 18, 43, 67a-d, 71 Chapter 18 questions 5-9, 26, 27a-e, 32 Acids and Bases Problem Set: Chapter 17 questions 5-7, 9, 11, 13, 18, 43, 67a-d, 71 Chapter 18 questions 5-9, 26, 27a-e, 32 Arrhenius Theory of Acids An acid base reaction involves the reaction of hydrogen

More information

Sketch the model representation of the first step in the dissociation of water. H 2. O (l) H + (aq) + OH- (aq) + H 2. OH - (aq) + H 3 O+ (aq)

Sketch the model representation of the first step in the dissociation of water. H 2. O (l) H + (aq) + OH- (aq) + H 2. OH - (aq) + H 3 O+ (aq) Lesson Objectives Students will: Create a physical representation of the autoionization of water using the water kit. Describe and produce a physical representation of the dissociation of a strong acid

More information

Chemistry Post-Enrolment Worksheet

Chemistry Post-Enrolment Worksheet Name: Chemistry Post-Enrolment Worksheet The purpose of this worksheet is to get you to recap some of the fundamental concepts that you studied at GCSE and introduce some of the concepts that will be part

More information

ATOMS. Multiple Choice Questions

ATOMS. Multiple Choice Questions Chapter 3 ATOMS AND MOLECULES Multiple Choice Questions 1. Which of the following correctly represents 360 g of water? (i) 2 moles of H 2 0 (ii) 20 moles of water (iii) 6.022 10 23 molecules of water (iv)

More information

Experiment 9: Acids and Bases Adapted from: Chemistry, Experimental Foundations, 4th Ed. Laboratory Manual, by Merrill, Parry & Bassow.

Experiment 9: Acids and Bases Adapted from: Chemistry, Experimental Foundations, 4th Ed. Laboratory Manual, by Merrill, Parry & Bassow. Chem 121 Lab Clark College Experiment 9: Acids and Bases Adapted from: Chemistry, Experimental Foundations, 4th Ed. Laboratory Manual, by Merrill, Parry & Bassow. Content Goals: Increase understanding

More information

Moles, Molecules, and Grams Worksheet Answer Key

Moles, Molecules, and Grams Worksheet Answer Key Moles, Molecules, and Grams Worksheet Answer Key 1) How many are there in 24 grams of FeF 3? 1.28 x 10 23 2) How many are there in 450 grams of Na 2 SO 4? 1.91 x 10 24 3) How many grams are there in 2.3

More information

Experiment 18: ph Measurements of Common Substances. Experiment 17: Reactions of Acids with Common Substances

Experiment 18: ph Measurements of Common Substances. Experiment 17: Reactions of Acids with Common Substances Experiment 18: ph Measurements of Common Substances and Experiment 17: Reactions of Acids with Common Substances What is this lab about? You mean what ARE THESE labs about? Ok, so what are THESE labs about?

More information

Calculation of Molar Masses. Molar Mass. Solutions. Solutions

Calculation of Molar Masses. Molar Mass. Solutions. Solutions Molar Mass Molar mass = Mass in grams of one mole of any element, numerically equal to its atomic weight Molar mass of molecules can be determined from the chemical formula and molar masses of elements

More information

Chapter 6. Solution, Acids and Bases

Chapter 6. Solution, Acids and Bases Chapter 6 Solution, Acids and Bases Mixtures Two or more substances Heterogeneous- different from place to place Types of heterogeneous mixtures Suspensions- Large particles that eventually settle out

More information

The Mole. Chapter 2. Solutions for Practice Problems

The Mole. Chapter 2. Solutions for Practice Problems Chapter 2 The Mole Note to teacher: You will notice that there are two different formats for the Sample Problems in the student textbook. Where appropriate, the Sample Problem contains the full set of

More information

Definition The property of exhibiting the qualities of a base

Definition The property of exhibiting the qualities of a base Acids and Bases Word Acidity Alkalinity Amphiprotic Amphoteric Arrhenius Acid Arrhenius Base Basicity Bronsted/Lowry Acid Bronsted/Lowry Base Buret Caustic Conjugate pair Corrosive Electrolyte Hydrolysis

More information

CHM 130LL: ph, Buffers, and Indicators

CHM 130LL: ph, Buffers, and Indicators CHM 130LL: ph, Buffers, and Indicators Many substances can be classified as acidic or basic. Acidic substances contain hydrogen ions, H +, while basic substances contain hydroxide ions, OH. The relative

More information

Acids and Bases 7. Have You Ever Wondered?

Acids and Bases 7. Have You Ever Wondered? Acids and Bases 7 Have You Ever Wondered? 1. Are all acids corrosive? 2. What is an amino acid? 3. Is vitamin C really an acid? Are all vitamins acids? 4. What is the difference between salt and sodium?

More information

INTI COLLEGE MALAYSIA A? LEVEL PROGRAMME CHM 111: CHEMISTRY MOCK EXAMINATION: DECEMBER 2000 SESSION. 37 74 20 40 60 80 m/e

INTI COLLEGE MALAYSIA A? LEVEL PROGRAMME CHM 111: CHEMISTRY MOCK EXAMINATION: DECEMBER 2000 SESSION. 37 74 20 40 60 80 m/e CHM111(M)/Page 1 of 5 INTI COLLEGE MALAYSIA A? LEVEL PROGRAMME CHM 111: CHEMISTRY MOCK EXAMINATION: DECEMBER 2000 SESSION SECTION A Answer ALL EIGHT questions. (52 marks) 1. The following is the mass spectrum

More information

1. What do you think is the definition of an acid? Of a base?

1. What do you think is the definition of an acid? Of a base? Concepts of ph Why? The level of acidity or basicity affects many important biological and environmental processes: enzymes function effectively only in narrowly defined ranges of ph; blood ph in part

More information

Formulas, Equations and Moles

Formulas, Equations and Moles Chapter 3 Formulas, Equations and Moles Interpreting Chemical Equations You can interpret a balanced chemical equation in many ways. On a microscopic level, two molecules of H 2 react with one molecule

More information

Chemistry 2014 Scoring Guidelines

Chemistry 2014 Scoring Guidelines AP Chemistry 2014 Scoring Guidelines 2014 The College Board. College Board, Advanced Placement Program, AP, AP Central, and the acorn logo are registered trademarks of the College Board. Visit the College

More information

Moles. Moles. Moles. Moles. Balancing Eqns. Balancing. Balancing Eqns. Symbols Yields or Produces. Like a recipe:

Moles. Moles. Moles. Moles. Balancing Eqns. Balancing. Balancing Eqns. Symbols Yields or Produces. Like a recipe: Like a recipe: Balancing Eqns Reactants Products 2H 2 (g) + O 2 (g) 2H 2 O(l) coefficients subscripts Balancing Eqns Balancing Symbols (s) (l) (aq) (g) or Yields or Produces solid liquid (pure liquid)

More information

Number of moles of solute = Concentration (mol. L ) x Volume of solution (litres) or n = C x V

Number of moles of solute = Concentration (mol. L ) x Volume of solution (litres) or n = C x V 44 CALCULATIONS INVOLVING SOLUTIONS INTRODUCTION AND DEFINITIONS Many chemical reactions take place in aqueous (water) solution. Quantities of such solutions are measured as volumes, while the amounts

More information

Soil Chemistry Ch. 2. Chemical Principles As Applied to Soils

Soil Chemistry Ch. 2. Chemical Principles As Applied to Soils Chemical Principles As Applied to Soils I. Chemical units a. Moles and Avogadro s number The numbers of atoms, ions or molecules are important in chemical reactions because the number, rather than mass

More information

Chapter 3 Stoichiometry

Chapter 3 Stoichiometry Chapter 3 Stoichiometry 3-1 Chapter 3 Stoichiometry In This Chapter As you have learned in previous chapters, much of chemistry involves using macroscopic measurements to deduce what happens between atoms

More information

Stoichiometry. Unit Outline

Stoichiometry. Unit Outline 3 Stoichiometry Unit Outline 3.1 The Mole and Molar Mass 3.2 Stoichiometry and Compound Formulas 3.3 Stoichiometry and Chemical Reactions 3.4 Stoichiometry and Limiting Reactants 3.5 Chemical Analysis

More information

Solubility of Salts - Ksp. Ksp Solubility

Solubility of Salts - Ksp. Ksp Solubility Solubility of Salts - Ksp We now focus on another aqueous equilibrium system, slightly soluble salts. These salts have a Solubility Product Constant, K sp. (We saw this in 1B with the sodium tetraborate

More information

Chapter 3: Stoichiometry

Chapter 3: Stoichiometry Chapter 3: Stoichiometry Key Skills: Balance chemical equations Predict the products of simple combination, decomposition, and combustion reactions. Calculate formula weights Convert grams to moles and

More information

Determination of the Amount of Acid Neutralized by an Antacid Tablet Using Back Titration

Determination of the Amount of Acid Neutralized by an Antacid Tablet Using Back Titration Determination of the Amount of Acid Neutralized by an Antacid Tablet Using Back Titration GOAL AND OVERVIEW Antacids are bases that react stoichiometrically with acid. The number of moles of acid that

More information

MOLECULAR MASS AND FORMULA MASS

MOLECULAR MASS AND FORMULA MASS 1 MOLECULAR MASS AND FORMULA MASS Molecular mass = sum of the atomic weights of all atoms in the molecule. Formula mass = sum of the atomic weights of all atoms in the formula unit. 2 MOLECULAR MASS AND

More information

Chapter 3 Mass Relationships in Chemical Reactions

Chapter 3 Mass Relationships in Chemical Reactions Chapter 3 Mass Relationships in Chemical Reactions Student: 1. An atom of bromine has a mass about four times greater than that of an atom of neon. Which choice makes the correct comparison of the relative

More information

English already has many collective nouns for fixed, given numbers of objects. Some of the more common collective nouns are shown in Table 7.1.

English already has many collective nouns for fixed, given numbers of objects. Some of the more common collective nouns are shown in Table 7.1. 96 Chapter 7: Calculations with Chemical Formulas and Chemical Reactions Chemical reactions are written showing a few individual atoms or molecules reacting to form a few atoms or molecules of products.

More information

TOPIC-1: CHEMICAL EQUILIBRIUM A MATTER OF BALANCE

TOPIC-1: CHEMICAL EQUILIBRIUM A MATTER OF BALANCE Chemistry 534 CHAPTER 6 Chemical Equilibrium The subject of any investigation is called a system. When the study involves experimentation, the system is said to be real. When the study involves ideas,

More information

STOICHIOMETRY UNIT 1 LEARNING OUTCOMES. At the end of this unit students will be expected to:

STOICHIOMETRY UNIT 1 LEARNING OUTCOMES. At the end of this unit students will be expected to: STOICHIOMETRY LEARNING OUTCOMES At the end of this unit students will be expected to: UNIT 1 THE MOLE AND MOLAR MASS define molar mass and perform mole-mass inter-conversions for pure substances explain

More information

Four common concentration units 1. Molarity 2. Weight Percent (Wt %), ppm, ppb 3. Molality 4. Mole Fraction. Molarity, M =

Four common concentration units 1. Molarity 2. Weight Percent (Wt %), ppm, ppb 3. Molality 4. Mole Fraction. Molarity, M = Four common concentration units 1. Molarity 2. Weight Percent (Wt %), ppm, ppb 3. Molality 4. Mole Fraction Molarity, M tells you how many s of solute are present in every liter of solution (solute-to-solution)

More information

Moles. Balanced chemical equations Molar ratios Mass Composition Empirical and Molecular Mass Predicting Quantities Equations

Moles. Balanced chemical equations Molar ratios Mass Composition Empirical and Molecular Mass Predicting Quantities Equations Moles Balanced chemical equations Molar ratios Mass Composition Empirical and Molecular Mass Predicting Quantities Equations Micro World atoms & molecules Macro World grams Atomic mass is the mass of an

More information

4.4 Calculations Involving the Mole Concept

4.4 Calculations Involving the Mole Concept 44 Section 43 Questions 1 Define Avogadro s constant, and explain its significance in quantitative analysis 2 Distinguish between the terms atomic mass and molar mass 3 Calculate the mass of a molecule

More information

MOLES AND MOLE CALCULATIONS

MOLES AND MOLE CALCULATIONS 35 MOLES ND MOLE CLCULTIONS INTRODUCTION The purpose of this section is to present some methods for calculating both how much of each reactant is used in a chemical reaction, and how much of each product

More information

Study Guide For Chapter 7

Study Guide For Chapter 7 Name: Class: Date: ID: A Study Guide For Chapter 7 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. The number of atoms in a mole of any pure substance

More information

Chem 31 Fall 2002. Chapter 3. Stoichiometry: Calculations with Chemical Formulas and Equations. Writing and Balancing Chemical Equations

Chem 31 Fall 2002. Chapter 3. Stoichiometry: Calculations with Chemical Formulas and Equations. Writing and Balancing Chemical Equations Chem 31 Fall 2002 Chapter 3 Stoichiometry: Calculations with Chemical Formulas and Equations Writing and Balancing Chemical Equations 1. Write Equation in Words -you cannot write an equation unless you

More information

Experiment 3: Extraction: Separation of an Acidic, a Basic and a Neutral Substance

Experiment 3: Extraction: Separation of an Acidic, a Basic and a Neutral Substance 1 Experiment 3: Extraction: Separation of an Acidic, a Basic and a Neutral Substance Read pp 142-155, 161-162, Chapter 10 and pp 163-173, Chapter 11, in LTOC. View the videos: 4.2 Extraction (Macroscale);

More information

Continuous process of sodium bicarbonate production by Solvay method

Continuous process of sodium bicarbonate production by Solvay method Continuous process of sodium bicarbonate production by Solvay method Manual to experiment nr 10 Instructor: Dr Tomasz S. Pawłowski 1 Goal of the experiment The goal of the experiment is introduction of

More information

Part One: Mass and Moles of Substance. Molecular Mass = sum of the Atomic Masses in a molecule

Part One: Mass and Moles of Substance. Molecular Mass = sum of the Atomic Masses in a molecule CHAPTER THREE: CALCULATIONS WITH CHEMICAL FORMULAS AND EQUATIONS Part One: Mass and Moles of Substance A. Molecular Mass and Formula Mass. (Section 3.1) 1. Just as we can talk about mass of one atom of

More information

Stoichiometry. Lecture Examples Answer Key

Stoichiometry. Lecture Examples Answer Key Stoichiometry Lecture Examples Answer Key Ex. 1 Balance the following chemical equations: 3 NaBr + 1 H 3 PO 4 3 HBr + 1 Na 3 PO 4 2 C 3 H 5 N 3 O 9 6 CO 2 + 3 N 2 + 5 H 2 O + 9 O 2 2 Ca(OH) 2 + 2 SO 2

More information

PROFESSIONAL DEVELOPMENT

PROFESSIONAL DEVELOPMENT PROFESSIONAL DEVELOPMENT AP Chemistry Acids and Bases Special Focus The College Board: Connecting Students to College Success The College Board is a not-for-profit membership association whose mission

More information

EDEXCEL INTERNATIONAL GCSE CHEMISTRY EDEXCEL CERTIFICATE IN CHEMISTRY ANSWERS SECTION E

EDEXCEL INTERNATIONAL GCSE CHEMISTRY EDEXCEL CERTIFICATE IN CHEMISTRY ANSWERS SECTION E EDEXCEL INTERNATIONAL GCSE CHEMISTRY EDEXCEL CERTIFICATE IN CHEMISTRY ANSWERS SECTION E (To save endless repetition, wherever they are included, comments are intended for homeschooling parents who may

More information

Chemistry Final Study Guide

Chemistry Final Study Guide Name: Class: Date: Chemistry Final Study Guide Multiple Choice Identify the choice that best completes the statement or answers the question. 1. The electrons involved in the formation of a covalent bond

More information

Acid-Base Indicator Useful Indicators

Acid-Base Indicator Useful Indicators Chemistry 101 - H Acids and Bases This presentation was created by Professor Carl H. Snyder Chemistry Department University of Miami Coral Gables, FL 33124 CSnyder@miami.edu Chapter 10 - Acids and Bases

More information

Concept 1. The meaning and usefulness of the mole. The mole (or mol) represents a certain number of objects.

Concept 1. The meaning and usefulness of the mole. The mole (or mol) represents a certain number of objects. Chapter 3. Stoichiometry: Mole-Mass Relationships in Chemical Reactions Concept 1. The meaning and usefulness of the mole The mole (or mol) represents a certain number of objects. SI def.: the amount of

More information

AP Chemistry 2006 Free-Response Questions

AP Chemistry 2006 Free-Response Questions AP Chemistry 006 Free-Response Questions The College Board: Connecting Students to College Success The College Board is a not-for-profit membership association whose mission is to connect students to college

More information

ION EXCHANGE FOR DUMMIES. An introduction

ION EXCHANGE FOR DUMMIES. An introduction ION EXCHANGE FOR DUMMIES An introduction Water Water is a liquid. Water is made of water molecules (formula H 2 O). All natural waters contain some foreign substances, usually in small amounts. The water

More information

Nomenclature and Household Items

Nomenclature and Household Items Nomenclature and Household Items NAME: DATE: PERIOD: Background: Many household items contain chemicals that are commonly used in everyday life. Some chemicals are edible while other compounds would be

More information

Chapter 14 Solutions

Chapter 14 Solutions Chapter 14 Solutions 1 14.1 General properties of solutions solution a system in which one or more substances are homogeneously mixed or dissolved in another substance two components in a solution: solute

More information

Guide To Preparation of Stock Standard Solutions

Guide To Preparation of Stock Standard Solutions chemias ft Guide To Preparation of Stock Standard Solutions First Edition May 2011 Na+ 1000 ppm Guide To Preparation Of Stock Standard Solutions By: CHEMIASOFT May 2011 Page 2 of 61 Page 3 of 61 Table

More information

Candidate Style Answer

Candidate Style Answer Candidate Style Answer Chemistry A Unit F321 Atoms, Bonds and Groups High banded response This Support Material booklet is designed to accompany the OCR GCE Chemistry A Specimen Paper F321 for teaching

More information

Experiment 7: Titration of an Antacid

Experiment 7: Titration of an Antacid 1 Experiment 7: Titration of an Antacid Objective: In this experiment, you will standardize a solution of base using the analytical technique known as titration. Using this standardized solution, you will

More information

Letter to the Student... 5 Test-Taking Checklist... 6 Next Generation Sunshine State Standards Correlation Chart... 7

Letter to the Student... 5 Test-Taking Checklist... 6 Next Generation Sunshine State Standards Correlation Chart... 7 Table of Contents Letter to the Student..................................... 5 Test-Taking Checklist.................................... 6 Next Generation Sunshine State Standards Correlation Chart...

More information

Chapter 2 Polar Covalent Bonds: Acids and Bases

Chapter 2 Polar Covalent Bonds: Acids and Bases John E. McMurry www.cengage.com/chemistry/mcmurry Chapter 2 Polar Covalent Bonds: Acids and Bases Modified by Dr. Daniela R. Radu Why This Chapter? Description of basic ways chemists account for chemical

More information

Mole Notes.notebook. October 29, 2014

Mole Notes.notebook. October 29, 2014 1 2 How do chemists count atoms/formula units/molecules? How do we go from the atomic scale to the scale of everyday measurements (macroscopic scale)? The gateway is the mole! But before we get to the

More information

Chapter 6 Chemical Calculations

Chapter 6 Chemical Calculations Chapter 6 Chemical Calculations 1 Submicroscopic Macroscopic 2 Chapter Outline 1. Formula Masses (Ch 6.1) 2. Percent Composition (supplemental material) 3. The Mole & Avogadro s Number (Ch 6.2) 4. Molar

More information

a. Cherry Garcia ice cream: heterogeneous mixture b. mayonnaise: colloid c, d, e. seltzer water, nail polish remover, and brass: solutions

a. Cherry Garcia ice cream: heterogeneous mixture b. mayonnaise: colloid c, d, e. seltzer water, nail polish remover, and brass: solutions Chapter 8 1 Chapter 8 Solutions Solutions to In-Chapter Problems 8.1 A heterogeneous miture does not have a uniform composition throughout a sample. A solution is a homogeneous miture that contains small

More information

Chapter 1: Moles and equations. Learning outcomes. you should be able to:

Chapter 1: Moles and equations. Learning outcomes. you should be able to: Chapter 1: Moles and equations 1 Learning outcomes you should be able to: define and use the terms: relative atomic mass, isotopic mass and formula mass based on the 12 C scale perform calculations, including

More information

6.8 Measuring the Acidity of Solutions Page 160

6.8 Measuring the Acidity of Solutions Page 160 6.8 Measuring the Acidity of Solutions Page 160 PRESCRIBED LEARNING OUTCOMES measure substances and solutions according to ph, solubility, and concentration KNOWLEDGE ph is the measure of the tendency

More information

Chapter 4. Chemical Composition. Chapter 4 Topics H 2 S. 4.1 Mole Quantities. The Mole Scale. Molar Mass The Mass of 1 Mole

Chapter 4. Chemical Composition. Chapter 4 Topics H 2 S. 4.1 Mole Quantities. The Mole Scale. Molar Mass The Mass of 1 Mole Chapter 4 Chemical Composition Chapter 4 Topics 1. Mole Quantities 2. Moles, Masses, and Particles 3. Determining Empirical Formulas 4. Chemical Composition of Solutions Copyright The McGraw-Hill Companies,

More information

Answers and Solutions to Text Problems

Answers and Solutions to Text Problems Chapter 7 Answers and Solutions 7 Answers and Solutions to Text Problems 7.1 A mole is the amount of a substance that contains 6.02 x 10 23 items. For example, one mole of water contains 6.02 10 23 molecules

More information

10 Cl atoms. 10 H2O molecules. 8.3 mol HCN = 8.3 mol N atoms 1 mol HCN. 2 mol H atoms 2.63 mol CH2O = 5.26 mol H atoms 1 mol CH O

10 Cl atoms. 10 H2O molecules. 8.3 mol HCN = 8.3 mol N atoms 1 mol HCN. 2 mol H atoms 2.63 mol CH2O = 5.26 mol H atoms 1 mol CH O Chem 100 Mole conversions and stoichiometry worksheet 1. How many Ag atoms are in.4 mol Ag atoms? 6.0 10 Ag atoms 4.4 mol Ag atoms = 1.46 10 Ag atoms 1 mol Ag atoms. How many Br molecules are in 18. mol

More information

Tutorial 2 FORMULAS, PERCENTAGE COMPOSITION, AND THE MOLE

Tutorial 2 FORMULAS, PERCENTAGE COMPOSITION, AND THE MOLE T-6 Tutorial 2 FORMULAS, PERCENTAGE COMPOSITION, AND THE MOLE FORMULAS: A chemical formula shows the elemental composition of a substance: the chemical symbols show what elements are present and the numerical

More information

UNIT (4) CALCULATIONS AND CHEMICAL REACTIONS

UNIT (4) CALCULATIONS AND CHEMICAL REACTIONS UNIT (4) CALCULATIONS AND CHEMICAL REACTIONS 4.1 Formula Masses Recall that the decimal number written under the symbol of the element in the periodic table is the atomic mass of the element. 1 7 8 12

More information

Stoichiometry. Web Resources Chem Team Chem Team Stoichiometry. Section 1: Definitions Define the following terms. Average Atomic mass - Molecule -

Stoichiometry. Web Resources Chem Team Chem Team Stoichiometry. Section 1: Definitions Define the following terms. Average Atomic mass - Molecule - Web Resources Chem Team Chem Team Section 1: Definitions Define the following terms Average Atomic mass - Molecule - Molecular mass - Moles - Avagadro's Number - Conservation of matter - Percent composition

More information

Chapter 1 The Atomic Nature of Matter

Chapter 1 The Atomic Nature of Matter Chapter 1 The Atomic Nature of Matter 6. Substances that cannot be decomposed into two or more simpler substances by chemical means are called a. pure substances. b. compounds. c. molecules. d. elements.

More information

Calculating Atoms, Ions, or Molecules Using Moles

Calculating Atoms, Ions, or Molecules Using Moles TEKS REVIEW 8B Calculating Atoms, Ions, or Molecules Using Moles TEKS 8B READINESS Use the mole concept to calculate the number of atoms, ions, or molecules in a sample TEKS_TXT of material. Vocabulary

More information

Fluid, Electrolyte & ph Balance

Fluid, Electrolyte & ph Balance , Electrolyte & ph Balance / Electrolyte / AcidBase Balance Body s: Cell function depends not only on continuous nutrient supply / waste removal, but also on the physical / chemical homeostasis of surrounding

More information

AP Chemistry 2015 Free-Response Questions

AP Chemistry 2015 Free-Response Questions AP Chemistry 2015 Free-Response Questions College Board, Advanced Placement Program, AP, AP Central, and the acorn logo are registered trademarks of the College Board. AP Central is the official online

More information

THE MOLE / COUNTING IN CHEMISTRY

THE MOLE / COUNTING IN CHEMISTRY 1 THE MOLE / COUNTING IN CHEMISTRY ***A mole is 6.0 x 10 items.*** 1 mole = 6.0 x 10 items 1 mole = 60, 00, 000, 000, 000, 000, 000, 000 items Analogy #1 1 dozen = 1 items 18 eggs = 1.5 dz. - to convert

More information

EXPERIMENT 12: Empirical Formula of a Compound

EXPERIMENT 12: Empirical Formula of a Compound EXPERIMENT 12: Empirical Formula of a Compound INTRODUCTION Chemical formulas indicate the composition of compounds. A formula that gives only the simplest ratio of the relative number of atoms in a compound

More information

Tuesday, November 27, 2012 Expectations:

Tuesday, November 27, 2012 Expectations: Tuesday, November 27, 2012 Expectations: Sit in assigned seat Get out Folder, Notebook, Periodic Table Have out: Spiral (notes), Learning Target Log (new) No Backpacks on tables Listen/Pay Attention Learning

More information

Determination of calcium by Standardized EDTA Solution

Determination of calcium by Standardized EDTA Solution Determination of calcium by Standardized EDTA Solution Introduction The classic method of determining calcium and other suitable cations is titration with a standardized solution of ethylenediaminetetraacetic

More information

Chemistry 65 Chapter 6 THE MOLE CONCEPT

Chemistry 65 Chapter 6 THE MOLE CONCEPT THE MOLE CONCEPT Chemists find it more convenient to use mass relationships in the laboratory, while chemical reactions depend on the number of atoms present. In order to relate the mass and number of

More information

Improving Silica Removal By EDI and GTM January 16, 2014 August 27, 2014 -- McIlvaine

Improving Silica Removal By EDI and GTM January 16, 2014 August 27, 2014 -- McIlvaine Improving Silica Removal By EDI and GTM January 16, 2014 August 27, 2014 McIlvaine Michael J. Snow, Ph.D. President SnowPure Water Technologies (USA) San Clemente, California Headquarters Electropure EDI

More information