# stoichiometry = the numerical relationships between chemical amounts in a reaction.

Size: px
Start display at page:

Download "stoichiometry = the numerical relationships between chemical amounts in a reaction."

Transcription

1 1 REACTIONS AND YIELD ANSWERS stoichiometry = the numerical relationships between chemical amounts in a reaction. 2C 8 H 18 (l) + 25O 2 16CO 2 (g) + 18H 2 O(g) From the equation, 16 moles of CO 2 (a greenhouse gas resulting in global warming) are produced for every 2 moles of octane burned (by combustion). Estimate the mass of CO 2 produced in 2004 by the combustion of 3.4 x g gasoline. Solution: number of moles = mass/molar mass; molar mass = molecular mass molecular masses: C 8 H 18 = ; CO 2 = gmol x / = x moles C8H18. stoichiometric ratio CO 2 : C 8 H 18 = 16: x x (16/2) = x moles CO 2 = 1.05 x g CO 2. limiting reactant (or reagent) = the reactant that limits the amount of product excess reactants = reactants not completely consumed theoretical yield = the amount of product that can be made from the limiting reactant actual yield = the amount of product that is made in a reaction; actual yield generally less than the theoretical yield, never more! percent yield = the efficiency of product recovery actual yield Percent yield = x 100% theoretical yield When 28.6 kg of C reacts with 88.2 kg of TiO 2, 42.8 kg of Ti are obtained. Find the Limiting Reactant, Theoretical Yield, and Percent Yield. TiO 2 (s) + 2 C(s) Ti(s) + 2CO(g) Solution: 1 mole TiO 2 gives 1 mole Ti; 2 moles C gives 1 mole Ti. molar masses C = 12.01; TiO 2 = 79.87; Ti = gmol -1. Number of moles of C = 2.38 x 10 3 moles Number of moles of TiO 2 = 2.38 x 10 3 moles x 10 3 moles Ti x 10 3 moles Ti TiO 2 = limiting reactant x 10 3 x = 52.9 kg Ti = theoretical yield Percent yield = 100% x 42.8 / 52.9 = 80.9 %. PRACTICE EXAMPLE ONE Mining companies use the following reaction to obtain iron from iron ore: Fe 2 O 3 (s) + 3CO(g) 2Fe(s) + 3CO 2 (g) The reaction of 167g of Fe 2 O 3 with 85.8g of CO produces 72.3g Fe. Find the limiting reagent, theoretical yield and percent yield.

2 2 CO is the limiting reagent since it only produces 114 g Fe (work out number of moles CO = 85.8/28.01= so max Fe = 2 / 3 x = 2 = 2 x = 114 g Fe) Therefore 114 g Fe is the theoretical yield; percentage yield = 100% x 72.3 / 114 = 63.4 % Making aqueous solutions When an ionic compound dissolves in water, the water molecules surround the cations and anions; e.g. KCl(s) K + (aq) + Cl - (aq). Heating the solution increases solubility. Substances such as potassium chloride or hydrogen chloride (strong acid) that completely dissociate into ions are strong electrolytes (solution conducts electrical current). Weak electrolytes dissolve mostly as molecules but partly dissociate into ions: CH 3 COOH(aq) CH 3 COO - (aq) + H + (aq) dilute solutions = small amount of solute compared to solvent concentrated solutions = large amount of solute compared to solvent amount of solute (in moles) Molarity = amount of solution (in L or dm 3 ) Find the molarity, M (or concentration, C) of a solution that has 25.5 g KBr dissolved in 1.75 L of solution Solution: molar mass KBr = gmol -1 number of moles = 25.5 / 119 = mol KBr molarity = / 1.75 = M (or mol dm -3 ). Dilution = make a solution less concentrated moles solute in solution 1 = moles solute in solution 2 M 1 V 1 = M 2 V 2 To what volume should you dilute L of 15.0 M NaOH to make 3.00 M NaOH? Solution: V 2 = M 1 V 1 / M 2 = 15 x 0.2 / 3 = 1 L PRACTICE EXAMPLE TWO What volume of a 6.00 M NaNO 3 solution should you use to make L of a 1.20 M NaNO 3 solution? V 2 = M 1 V 1 /M 2 = 1.20 x / 6 = L

3 3 What volume of M KCl is required to completely react with L of M Pb(NO 3 ) 2 in the reaction 2KCl(aq) + Pb(NO 3 ) 2 (aq) PbCl 2 (s) + 2 KNO 3 (aq)? 1 L Pb(NO 3 ) 2 = mol, 1 L KCl = mol, stoichiometry: 1 mol Pb(NO 3 ) 2 reacts with 2 mol KCl Number of moles of Pb(NO 3 ) 2 used = molarity x volume = moles Number of moles of KCl used = moles x 2 = moles volume KCl = moles / molarity = /0.150 = 0.35 L PRACTICE EXAMPLE THREE Consider the following reaction: Li 2 S(aq) + Co(NO 3 ) 2 (aq) 2LiNO 3 (aq) + CoS(S) What volume of M Li 2 S solution is required to completely react with 125 ml of M Co(NO 3 ) 2? Stoichiometry: 1:1 so number of moles Co(NO 3 ) 2 = x = moles = volume Li 2 S = 0.031/0.150 = L= 208 ml soluble = compounds that dissolve in a solvent (e.g. NaCl dissolves in water) insoluble = compounds that do not dissolve (e.g. AgCl does not) Most Group I compounds are soluble in water (e.g. NaOH, Na 2 SO 4 ). Some Group II compounds are soluble (e.g. CaCl 2 ), slightly soluble e.g. Ca(OH) 2, others are not (e.g. CaSO 4 ). Many ammonium NH 4 + compounds are soluble (e.g. NH 4 Cl) and ALL NITRATES (e.g. Ca(NO 3 ) 2 ) are soluble. Precipitation reactions = reactions between aqueous solutions of ionic compounds that produce an ionic compound that is insoluble (precipitate) in water: 2KI(aq) + Pb(NO 3 ) 2 (aq) PbI 2 (s) + 2 KNO 3 (aq); PbI 2 (s) is the precipitate Discussed in more detail (book p. 153). Writing and simplifying equations molecular equations = equations which describe the chemicals put into the water and the product molecules molecular equations, e.g. 2KI(aq) + Pb(NO 3 ) 2 (aq) PbI 2 (s) + 2 KNO 3 (aq) complete ionic equations = equations which describe the actual dissolved species: 2K + (aq) + 2I - (aq) + Pb 2+ (aq) + 2NO 3 2- (aq) 2K + (aq) + 2NO 3 2- (aq) + PbI 2 (s) ions that are both reactants and products are called spectator ions (they do not react and remain in the solution)

4 4 net ionic equation = an ionic equation in which the spectator ions are removed: Pb 2+ (aq) + 2I - (aq) PbI 2 (s) neutralization reactions = the acid and base neutralize each other s properties 2HNO 3 (aq) + Ca(OH) 2 (aq) Ca(NO 3 ) 2 (aq) + 2 H 2 O(l) the net ionic equation for an acid-base reaction is: H + (aq) + OH (aq) H 2 O(l) PRACTICE EXAMPLE FOUR Write complete ionic and net ionic equations for each reaction: K 2 SO 4 (aq) + CaI 2 (aq) CaSO 4 (s) + KI(aq) NH 4 Cl(aq) + NaOH(aq) NH 3 (g) + NaCl(aq) + H 2 O(l) 2K + (aq) + SO 4 (aq) + Ca 2+ (aq)+ 2 I - (aq) CaSO 4 (s) + 2K+(aq) + 2I - (aq) = Ca 2+ (aq)+ SO 4 2- (aq) CaSO 4 (s) NH 4 + (aq) + Cl - (aq) + Na + (aq) + OH - (aq) NH 3 (g) + Na+(aq) + Cl - (aq) + H 2 O(l) = NH 4 + (aq) + OH - (aq) NH 3 (g) + H 2 O(l) acids ionize in water to form H + ions more precisely, the H from the acid molecule is donated to a water molecule to form hydronium ion, H 3 O +. A proton (H + ) cannot exist on its own in water! bases dissociate in water to form OH ions bases, such as NH 3, that do not contain OH ions, produce OH by pulling H off water molecules acid + base salt + water titration - a solution s concentration is determined by reacting it with another material and using stoichiometry (involving a chemical equation and calculation). An indicator permanently changes colour at the end-point (just finished). For example, if we know the concentration and precise volume of the alkali but only the volume of acid of unknown concentration, we can determine its concentration. Titration can be used for many ionic reactions. n 1 A + n 2 B products (e.g. salt + water) C 1 x V 1 = n 1 C 1 x V 1 x n or 2 C C 2 x V 2 n 2 = 2 n 1 x V 2

5 ml of M NaOH(aq) reacts ml of HCl(aq) solution. What is the concentration of the acid? The formula can be used with ml (for both solutions) or converted to L for both solutions. NaOH(aq) + HCl(aq) NaCl(aq) + H 2 O(l) C 1 concentration = M NaOH(aq); C 2 =? V 1 volume = ml NaOH(aq); V 2 = ml n 1 stoichiometric value = 1 for NaOH; n 2 = 1 for HCl C 2 = x x 1 / 1 x = M HCl(aq) Some neutralization reactions evolve gases; the intermediate carbonic acid (H 2 CO 3 ) thus decomposes, e.g. Na 2 CO 3 (aq) + 2HNO 3 (aq) 2NaNO 3 (aq) + CO 2 (g) + H 2 O(l) PRACTICE EXAMPLE FIVE A ml sample of an unknown H 3 PO 4 solution is titrated with a M NaOH solution. The end-point (equivalence point) is reached when ml of NaOH solution is added. What is the concentration of the unknown H 3 PO 4 solution? 3NaOH(aq) + H 3 PO 4 (aq) Na 3 PO 4 (aq) + 3H 2 O(l) Stoichiometry: n 1 = 3; n 2 = 1 so C 2 = x x 1 / x 3 = M H 3 PO 4 REDOX REACTIONS REDOX (oxidation-reduction) reactions = transferring electrons from one atom to another Many involve the use of O 2, Cl 2 etc. 4 Fe(s) + 3O 2 (g) 2 Fe 2 O 3 (s); the iron has transferred its electrons to the oxygen atoms Combustion (molecular - involve the use of O 2 ) is also REDOX, e.g. H 2 (g) + O 2 (g) 2H 2 O(l) oxidation occurs when an atom s oxidation state increases during a reaction (Fe(0) to Fe +3). LOSS OF ELECTRONS reduction occurs when an atom s oxidation state decreases during a reaction (O (0) to O (- 2). GAIN OF ELECTRONS In a REDOX reaction, the oxidizing agent is always reduced and the reducing agent always oxidized.

6 6 C +2S CS 2 carbon is the reducing agent (0 to +4) and sulphur the oxidizing agent (0 to -2). Oxidation state and ionic charges are not to be confused; see the table in book p.164. for single atoms with a charge (e.g. Fe 3+, O 2- ) the oxidation state is often the charge! oxygen is nearly always -2 (exception KO 2 ). Group I = +1; Group 2 = +2 Transition metals have variable oxidation states (e.g. chromium from +2 to +6) K 2 Cr 2 O 7 : Cr = +6 = potassium chromate(vi) elements (e.g. O 2 oxidation state = zero (0). Metals have positive oxidation states. In a neutral atom or formula the sum ( ) of the oxidation states = 0. An ion is equal to the charge of the ion. SO 4 2-, and H 2 SO 4 sulphur has oxidation state of +6. PRACTICE EXAMPLE SIX What is the oxidation state of Cl in each ion? 1. a) ClO - +1 b)clo c)clo d)clo Determine the oxidizing and reducing agent: a) Al(s) + 3Ag+(aq) Al 3+ (aq) + 2Ag(s) b) NaI 2 (aq) + Cl 2 (g) 2NaCl(aq) + I 2 (aq) a) oxidizing agent = reduced (gain in electrons); reducing agent = oxidized (loss of electrons) so reducing agent = Al; oxidizing agent = Ag +. b) I - = reducing agent; Cl 2 = oxidizing agent. COMBUSTION REACTIONS We have encountered several combustion reactions so far. Common ones include burning elemental carbon, hydrogen, sulphur, phosphorous, hydrocarbons (e.g. methane) or alcohol in air or oxygen. They give off heat (exothermic, H < 0 typically about 2000 KJmol -1 ) and light. See book, p for equations. Equations must be balanced in an exam (number of atoms on the left = number of atoms on the right).

### Chemical Equations. Chemical Equations. Chemical reactions describe processes involving chemical change

Chemical Reactions Chemical Equations Chemical reactions describe processes involving chemical change The chemical change involves rearranging matter Converting one or more pure substances into new pure

### Chemical Reactions in Water Ron Robertson

Chemical Reactions in Water Ron Robertson r2 f:\files\courses\1110-20\2010 possible slides for web\waterchemtrans.doc Properties of Compounds in Water Electrolytes and nonelectrolytes Water soluble compounds

### Aqueous Solutions. Water is the dissolving medium, or solvent. Some Properties of Water. A Solute. Types of Chemical Reactions.

Aqueous Solutions and Solution Stoichiometry Water is the dissolving medium, or solvent. Some Properties of Water Water is bent or V-shaped. The O-H bonds are covalent. Water is a polar molecule. Hydration

### H 2 + O 2 H 2 O. - Note there is not enough hydrogen to react with oxygen - It is necessary to balance equation.

CEMICAL REACTIONS 1 ydrogen + Oxygen Water 2 + O 2 2 O reactants product(s) reactant substance before chemical change product substance after chemical change Conservation of Mass During a chemical reaction,

### 6 Reactions in Aqueous Solutions

6 Reactions in Aqueous Solutions Water is by far the most common medium in which chemical reactions occur naturally. It is not hard to see this: 70% of our body mass is water and about 70% of the surface

### Solution a homogeneous mixture = A solvent + solute(s) Aqueous solution water is the solvent

Solution a homogeneous mixture = A solvent + solute(s) Aqueous solution water is the solvent Water a polar solvent: dissolves most ionic compounds as well as many molecular compounds Aqueous solution:

### Chapter 8: Chemical Equations and Reactions

Chapter 8: Chemical Equations and Reactions I. Describing Chemical Reactions A. A chemical reaction is the process by which one or more substances are changed into one or more different substances. A chemical

### Chapter 5. Chemical Reactions and Equations. Introduction. Chapter 5 Topics. 5.1 What is a Chemical Reaction

Introduction Chapter 5 Chemical Reactions and Equations Chemical reactions occur all around us. How do we make sense of these changes? What patterns can we find? 1 2 Copyright The McGraw-Hill Companies,

### Appendix D. Reaction Stoichiometry D.1 INTRODUCTION

Appendix D Reaction Stoichiometry D.1 INTRODUCTION In Appendix A, the stoichiometry of elements and compounds was presented. There, the relationships among grams, moles and number of atoms and molecules

### Chemical Equations and Chemical Reactions. Chapter 8.1

Chemical Equations and Chemical Reactions Chapter 8.1 Objectives List observations that suggest that a chemical reaction has taken place List the requirements for a correctly written chemical equation.

### 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)

### 1/7/2013. Chapter 9. Chemical Reactions in Aqueous Solutions. Chemistry: Atoms First Julia Burdge & Jason Overby. Reactions in Aqueous Solutions 9.

Chemistry: Atoms First Julia Burdge & Jason Overby 9 Reactions in Aqueous s Chapter 9 Chemical Reactions in Aqueous s Kent L. McCorkle Cosumnes River College Sacramento, CA Copyright (c) The McGraw-Hill

### 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

### Stoichiometry and Aqueous Reactions (Chapter 4)

Stoichiometry and Aqueous Reactions (Chapter 4) Chemical Equations 1. Balancing Chemical Equations (from Chapter 3) Adjust coefficients to get equal numbers of each kind of element on both sides of arrow.

### Chemistry B11 Chapter 4 Chemical reactions

Chemistry B11 Chapter 4 Chemical reactions Chemical reactions are classified into five groups: A + B AB Synthesis reactions (Combination) H + O H O AB A + B Decomposition reactions (Analysis) NaCl Na +Cl

### 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

### Formulae, stoichiometry and the mole concept

3 Formulae, stoichiometry and the mole concept Content 3.1 Symbols, Formulae and Chemical equations 3.2 Concept of Relative Mass 3.3 Mole Concept and Stoichiometry Learning Outcomes Candidates should be

### 4.1 Aqueous Solutions. Chapter 4. Reactions in Aqueous Solution. Electrolytes. Strong Electrolytes. Weak Electrolytes

Chapter 4 Reactions in Aqueous Solution 4.1 Aqueous Solutions Solution homogeneous mixture of 2 or more substances Solute the substance present in a smaller amount (usually solid in Chap. 4) Solvent the

### Chemistry 51 Chapter 8 TYPES OF SOLUTIONS. A solution is a homogeneous mixture of two substances: a solute and a solvent.

TYPES OF SOLUTIONS A solution is a homogeneous mixture of two substances: a solute and a solvent. Solute: substance being dissolved; present in lesser amount. Solvent: substance doing the dissolving; present

### 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

### 2. DECOMPOSITION REACTION ( A couple have a heated argument and break up )

TYPES OF CHEMICAL REACTIONS Most reactions can be classified into one of five categories by examining the types of reactants and products involved in the reaction. Knowing the types of reactions can help

### Chemistry: Chemical Equations

Chemistry: Chemical Equations Write a balanced chemical equation for each word equation. Include the phase of each substance in the equation. Classify the reaction as synthesis, decomposition, single replacement,

### 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

### REVIEW QUESTIONS Chapter 8

Chemistry 51 ANSWER KEY REVIEW QUESTIONS Chapter 8 1. Identify each of the diagrams below as strong electrolyte, weak electrolyte or non-electrolyte: (a) Non-electrolyte (no ions present) (b) Weak electrolyte

### 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

### Tutorial 4 SOLUTION STOICHIOMETRY. Solution stoichiometry calculations involve chemical reactions taking place in solution.

T-27 Tutorial 4 SOLUTION STOICHIOMETRY Solution stoichiometry calculations involve chemical reactions taking place in solution. Of the various methods of expressing solution concentration the most convenient

### Aqueous Ions and Reactions

Aqueous Ions and Reactions (ions, acids, and bases) Demo NaCl(aq) + AgNO 3 (aq) AgCl (s) Two clear and colorless solutions turn to a cloudy white when mixed Demo Special Light bulb in water can test for

### Experiment 8 - Double Displacement Reactions

Experiment 8 - Double Displacement Reactions A double displacement reaction involves two ionic compounds that are dissolved in water. In a double displacement reaction, it appears as though the ions are

### Chapter 7: Chemical Reactions

Chapter 7 Page 1 Chapter 7: Chemical Reactions A chemical reaction: a process in which at least one new substance is formed as the result of a chemical change. A + B C + D Reactants Products Evidence that

### 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

### Chemical Equations & Stoichiometry

Chemical Equations & Stoichiometry Chapter Goals Balance equations for simple chemical reactions. Perform stoichiometry calculations using balanced chemical equations. Understand the meaning of the term

### NET IONIC EQUATIONS. A balanced chemical equation can describe all chemical reactions, an example of such an equation is:

NET IONIC EQUATIONS A balanced chemical equation can describe all chemical reactions, an example of such an equation is: NaCl + AgNO 3 AgCl + NaNO 3 In this case, the simple formulas of the various reactants

### Balance the following equation: KClO 3 + C 12 H 22 O 11 KCl + CO 2 + H 2 O

Balance the following equation: KClO 3 + C 12 H 22 O 11 KCl + CO 2 + H 2 O Ans: 8 KClO 3 + C 12 H 22 O 11 8 KCl + 12 CO 2 + 11 H 2 O 3.2 Chemical Symbols at Different levels Chemical symbols represent

### IB Chemistry. DP Chemistry Review

DP Chemistry Review Topic 1: Quantitative chemistry 1.1 The mole concept and Avogadro s constant Assessment statement Apply the mole concept to substances. Determine the number of particles and the amount

### Chapter 11. Electrochemistry Oxidation and Reduction Reactions. Oxidation-Reduction Reactions. Oxidation-Reduction Reactions

Oxidation-Reduction Reactions Chapter 11 Electrochemistry Oxidation and Reduction Reactions An oxidation and reduction reaction occurs in both aqueous solutions and in reactions where substances are burned

### 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

### Chemical Quantities and Aqueous Reactions

4 Chemical Quantities and Aqueous Reactions I feel sorry for people who don t understand anything about chemistry. They are missing an important source of happiness. Linus Pauling (1901 1994) 4.1 Climate

### 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

### Aqueous Chemical Reactions

Name: Date: Lab Partners: Lab section: Aqueous Chemical Reactions The purpose of this lab is to introduce you to three major categories of reactions that occur in aqueous solutions: precipitation reactions,

### Balancing Chemical Equations Worksheet

Balancing Chemical Equations Worksheet Student Instructions 1. Identify the reactants and products and write a word equation. 2. Write the correct chemical formula for each of the reactants and the products.

### 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.

### Chapter 17. How are acids different from bases? Acid Physical properties. Base. Explaining the difference in properties of acids and bases

Chapter 17 Acids and Bases How are acids different from bases? Acid Physical properties Base Physical properties Tastes sour Tastes bitter Feels slippery or slimy Chemical properties Chemical properties

### Chemical Reactions 2 The Chemical Equation

Chemical Reactions 2 The Chemical Equation INFORMATION Chemical equations are symbolic devices used to represent actual chemical reactions. The left side of the equation, called the reactants, is separated

### Chapter 17. The best buffer choice for ph 7 is NaH 2 PO 4 /Na 2 HPO 4. 19)

Chapter 17 2) a) HCl and CH 3 COOH are both acids. A buffer must have an acid/base conjugate pair. b) NaH 2 PO 4 and Na 2 HPO 4 are an acid/base conjugate pair. They will make an excellent buffer. c) H

### 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

### Chapter 8 - Chemical Equations and Reactions

Chapter 8 - Chemical Equations and Reactions 8-1 Describing Chemical Reactions I. Introduction A. Reactants 1. Original substances entering into a chemical rxn B. Products 1. The resulting substances from

### Practical Lesson No 4 TITRATIONS

Practical Lesson No 4 TITRATIONS Reagents: 1. NaOH standard solution 0.1 mol/l 2. H 2 SO 4 solution of unknown concentration 3. Phenolphthalein 4. Na 2 S 2 O 3 standard solution 0.1 mol/l 5. Starch solution

### 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

### SAMPLE PROBLEM 8.1. Solutions of Electrolytes and Nonelectrolytes SOLUTION STUDY CHECK

Solutions of Electrolytes and Nonelectrolytes SAMPLE PROBLEM 8.1 Indicate whether solutions of each of the following contain only ions, only molecules, or mostly molecules and a few ions: a. Na 2 SO 4,

### Steps for balancing a chemical equation

The Chemical Equation: A Chemical Recipe Dr. Gergens - SD Mesa College A. Learn the meaning of these arrows. B. The chemical equation is the shorthand notation for a chemical reaction. A chemical equation

### 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

### Chapter 4 Chemical Reactions

Chapter 4 Chemical Reactions I) Ions in Aqueous Solution many reactions take place in water form ions in solution aq solution = solute + solvent solute: substance being dissolved and present in lesser

### 4.1 Stoichiometry. 3 Basic Steps. 4. Stoichiometry. Stoichiometry. Butane Lighter 2C 4 H 10 + 13O 2 10H 2 O + 8CO 2

4. Stoichiometry 1. Stoichiometric Equations 2. Limiting Reagent Problems 3. Percent Yield 4. Limiting Reagent Problems 5. Concentrations of Solutes 6. Solution Stoichiometry 7. ph and Acid Base Titrations

### MOLARITY = (moles solute) / (vol.solution in liter units)

CHEM 101/105 Stoichiometry, as applied to Aqueous Solutions containing Ionic Solutes Lect-05 MOLES - a quantity of substance. Quantities of substances can be expressed as masses, as numbers, or as moles.

### CHEMICAL REACTIONS. Chemistry 51 Chapter 6

CHEMICAL REACTIONS A chemical reaction is a rearrangement of atoms in which some of the original bonds are broken and new bonds are formed to give different chemical structures. In a chemical reaction,

### 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

### Acid-Base Chemistry. Brønsted-Lowry Acids & Bases

Acid-Base Chemistry ν There are a couple of ways to define acids and bases ν Brønsted-Lowry acids and bases ν Acid: H + ion donor ν Base: H + ion acceptor ν Lewis acids and bases ν Acid: electron pair

### Problem Solving. Stoichiometry of Gases

Skills Worksheet Problem Solving Stoichiometry of Gases Now that you have worked with relationships among moles, mass, and volumes of gases, you can easily put these to work in stoichiometry calculations.

### Chapter 6 Notes Science 10 Name:

6.1 Types of Chemical Reactions a) Synthesis (A + B AB) Synthesis reactions are also known as reactions. When this occurs two or more reactants (usually elements) join to form a. A + B AB, where A and

### Molarity of Ions in Solution

APPENDIX A Molarity of Ions in Solution ften it is necessary to calculate not only the concentration (in molarity) of a compound in aqueous solution but also the concentration of each ion in aqueous solution.

### CHEMISTRY 101 EXAM 3 (FORM B) DR. SIMON NORTH

1. Is H 3 O + polar or non-polar? (1 point) a) Polar b) Non-polar CHEMISTRY 101 EXAM 3 (FORM B) DR. SIMON NORTH 2. The bond strength is considerably greater in HF than in the other three hydrogen halides

### Experiment 1 Chemical Reactions and Net Ionic Equations

Experiment 1 Chemical Reactions and Net Ionic Equations I. Objective: To predict the products of some displacement reactions and write net ionic equations. II. Chemical Principles: A. Reaction Types. Chemical

### Calculations and Chemical Equations. Example: Hydrogen atomic weight = 1.008 amu Carbon atomic weight = 12.001 amu

Calculations and Chemical Equations Atomic mass: Mass of an atom of an element, expressed in atomic mass units Atomic mass unit (amu): 1.661 x 10-24 g Atomic weight: Average mass of all isotopes of a given

### 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

### Chapter 3. Chemical Reactions and Reaction Stoichiometry. Lecture Presentation. James F. Kirby Quinnipiac University Hamden, CT

Lecture Presentation Chapter 3 Chemical Reactions and Reaction James F. Kirby Quinnipiac University Hamden, CT The study of the mass relationships in chemistry Based on the Law of Conservation of Mass

### UNIT (6) ACIDS AND BASES

UNIT (6) ACIDS AND BASES 6.1 Arrhenius Definition of Acids and Bases Definitions for acids and bases were proposed by the Swedish chemist Savante Arrhenius in 1884. Acids were defined as compounds that

### Balancing Reaction Equations Oxidation State Reduction-oxidation Reactions

Balancing Reaction Equations Oxidation State Reduction-oxidation Reactions OCN 623 Chemical Oceanography Balanced chemical reactions are the math of chemistry They show the relationship between the reactants

### 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

### Honors Chemistry: Unit 6 Test Stoichiometry PRACTICE TEST ANSWER KEY Page 1. A chemical equation. (C-4.4)

Honors Chemistry: Unit 6 Test Stoichiometry PRACTICE TEST ANSWER KEY Page 1 1. 2. 3. 4. 5. 6. Question What is a symbolic representation of a chemical reaction? What 3 things (values) is a mole of a chemical

### Acid/base Definitions. Acid/Base Definitions. Acid / Base Chemistry. Acid/Base Definitions. Identifying Acids and Bases

Acids Identifying Acids and Bases Acid (anhydrides) contains H+ ions as the cation, with and other element as the anion Non-metal oxide H2SO4 HI P2O5 Bases Base (anhydrides) Contains OH- as the anion Combined

### Unit 2: Quantities in Chemistry

Mass, Moles, & Molar Mass Relative quantities of isotopes in a natural occurring element (%) E.g. Carbon has 2 isotopes C-12 and C-13. Of Carbon s two isotopes, there is 98.9% C-12 and 11.1% C-13. Find

### Writing, Balancing and Predicting Products of Chemical Reactions.

Writing, Balancing and Predicting Products of Chemical Reactions. A chemical equation is a concise shorthand expression which represents the relative amount of reactants and products involved in a chemical

### 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)

### 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

### 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

### TOPIC 11: Acids and Bases

TOPIC 11: Acids and Bases ELECTROLYTES are substances that when dissolves in water conduct electricity. They conduct electricity because they will break apart into Ex. NaCl(s)! Na + (aq) + Cl - (aq), and

### HOMEWORK 4A. Definitions. Oxidation-Reduction Reactions. Questions

HOMEWORK 4A Oxidation-Reduction Reactions 1. Indicate whether a reaction will occur or not in each of following. Wtiring a balcnced equation is not necessary. (a) Magnesium metal is added to hydrochloric

### CHM1 Review for Exam 12

Topics Solutions 1. Arrhenius Acids and bases a. An acid increases the H + concentration in b. A base increases the OH - concentration in 2. Strong acids and bases completely dissociate 3. Weak acids and

### CHAPTERS 15 FAKE TEST QUESTIONS. 1. According to the Brønsted Lowry definition, which species can function both as an acid and as a base?

You might need to know the following K values: CHAPTERS 15 FAKE TEST QUESTIONS CH 3 COOH K a = 1.8 x 10 5 Benzoic Acid K a = 6.5 x 10 5 HNO 2 K a = 4.5 x 10 4 NH 3 K b = 1.8 x 10 5 HF K a = 7.2 x 10 4

### Chem101: General Chemistry Lecture 9 Acids and Bases

: General Chemistry Lecture 9 Acids and Bases I. Introduction A. In chemistry, and particularly biochemistry, water is the most common solvent 1. In studying acids and bases we are going to see that water

### CHEMICAL REACTIONS AND REACTING MASSES AND VOLUMES

CHEMICAL REACTIONS AND REACTING MASSES AND VOLUMES The meaning of stoichiometric coefficients: 2 H 2 (g) + O 2 (g) 2 H 2 O(l) number of reacting particles 2 molecules of hydrogen react with 1 molecule

Sample Exercise 17.1 Calculating the ph When a Common Ion is Involved What is the ph of a solution made by adding 0.30 mol of acetic acid and 0.30 mol of sodium acetate to enough water to make 1.0 L of

### Chem 1100 Chapter Three Study Guide Answers Outline I. Molar Mass and Moles A. Calculations of Molar Masses

Chem 1100 Chapter Three Study Guide Answers Outline I. Molar Mass and Moles A. Calculations of Molar Masses B. Calculations of moles C. Calculations of number of atoms from moles/molar masses 1. Avagadro

### CHEM 110: CHAPTER 3: STOICHIOMETRY: CALCULATIONS WITH CHEMICAL FORMULAS AND EQUATIONS

1 CHEM 110: CHAPTER 3: STOICHIOMETRY: CALCULATIONS WITH CHEMICAL FORMULAS AND EQUATIONS The Chemical Equation A chemical equation concisely shows the initial (reactants) and final (products) results of

### IB Chemistry 1 Mole. One atom of C-12 has a mass of 12 amu. One mole of C-12 has a mass of 12 g. Grams we can use more easily.

The Mole Atomic mass units and atoms are not convenient units to work with. The concept of the mole was invented. This was the number of atoms of carbon-12 that were needed to make 12 g of carbon. 1 mole

### Unit 4 Conservation of Mass and Stoichiometry

9.1 Naming Ions I. Monatomic Ions A. Monatomic ions 1. Ions formed from a single atom Unit 4 Conservation of Mass and Stoichiometry B. Naming Monatomic Ions 1. Monatomic cations are a. Identified by the

### Types of Reactions. CHM 130LL: Chemical Reactions. Introduction. General Information

Introduction CHM 130LL: Chemical Reactions We often study chemistry to understand how and why chemicals (reactants) can be transformed into different chemicals (products) via a chemical reaction: Reactants

### 2. Write the chemical formula(s) of the product(s) and balance the following spontaneous reactions.

1. Using the Activity Series on the Useful Information pages of the exam write the chemical formula(s) of the product(s) and balance the following reactions. Identify all products phases as either (g)as,

### ph: Measurement and Uses

ph: Measurement and Uses One of the most important properties of aqueous solutions is the concentration of hydrogen ion. The concentration of H + (or H 3 O + ) affects the solubility of inorganic and organic

### 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

### 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

### Chapter 3! Stoichiometry: Calculations with Chemical Formulas and Equations. Stoichiometry

Chapter 3! : Calculations with Chemical Formulas and Equations Anatomy of a Chemical Equation CH 4 (g) + 2O 2 (g) CO 2 (g) + 2 H 2 O (g) Anatomy of a Chemical Equation CH 4 (g) + 2 O 2 (g) CO 2 (g) + 2

### 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.

### Chapter 5, Calculations and the Chemical Equation

1. How many iron atoms are present in one mole of iron? Ans. 6.02 1023 atoms 2. How many grams of sulfur are found in 0.150 mol of sulfur? [Use atomic weight: S, 32.06 amu] Ans. 4.81 g 3. How many moles

### 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

### 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)

### Acid/Base Definition. Acid/Base Reactions. Major vs. Minor Species. Terms/Items you Need to Know. you need to memorize these!!

Acid/Base Reactions some covalent compounds have weakly bound H atoms and can lose them to water (acids) some compounds produce OH in water solutions when they dissolve (bases) acid/base reaction are very

### General Chemistry II Chapter 20

1 General Chemistry II Chapter 0 Ionic Equilibria: Principle There are many compounds that appear to be insoluble in aqueous solution (nonelectrolytes). That is, when we add a certain compound to water