Sample Problem (mole-mass)

Size: px
Start display at page:

Download "Sample Problem (mole-mass)"

Transcription

1 Name: KEY Class: Sample Problem (mole-mass) Potassium chlorate is sometimes decomposed in the laboratory to generate oxygen. What mass of KClO 3 do you need to produce 0.50 moles of O 2? 2 KClO 3 (s) 2 KCl(s) + 3 O 2 (g). What do you know? (What are the facts?) Amount of O 2 in moles: 0.5 mol O 2 Where do you want to go? (What is the unknown?) Mass of potassium chlorate: mass of KClO 3 How do you get there? (conversion factor set-up) What steps are needed to calculate the mass of KClO 3 needed to produce 0.50 moles O 2? 0.5 mol O 2 x 2 mol KClO 3 x 122 g KClO 3 = 40.7 g KClO mol O 2 1 mol KClO 3 Does it make sense? Are the units correct? yes 1

2 Practice Problems (Mole-Mass or Mass-Mole) 1. Phosphorus burns in air to produce a phosphorus oxide in the following reaction: 4 P (s) + 5_O 2 P 4 O 10 (s). a. What mass of phosphorus will be needed to produce 3.25 moles of P 4 O 10? 3.25 mol P 4 O 10 x _4 mol P x _31 g P_ = 403 g P 1 1 mol P 4 O 10 1 mol P b. If moles of phosphorus burn, what mass of oxygen is used? What mass of P 4 O 10 is produced? (1) mol P X 5 mol O 2 x 32 g O2 = g O mol P 1 mol O 2 (2) mol P x 1 mol P 4 O 10 x 284 g P 4 O 10 = g P 4 O mol P 1 mol P 4 O Hydrogen peroxide breaks down, releasing oxygen, in the following reaction: 2 H 2 O 2 (aq) 2 H 2 O (l) + O 2 (g) a. What mass of oxygen is produced when moles of H 2 O 2 decompose? 1.84 mol O 2 x _1 mol O 2 _ x _32 g O 2 = g O mol H 2 O 2 1 mol O 2 b. What mass of water is produced when 5.0 moles O 2 are produced by this reaction? 5 mol O 2 x 2 mol H 2 O x 18 g H 2 O = 180 g H 2 O 1 2 mol H 2 O 2 1 mol H 2 O 3. Sodium carbonate reacts with nitric acid according to the following equation: Na 2 CO 3 (s) + _2_HNO 3 (aq) _2_NaNO 3 (aq) + CO 2 (g) + H 2 O(l) a. How many moles of Na 2 CO 3 are required to produce g of NaNO 3? 100 g NaNO 3 x 1 mol NaNO 3 x 1 mol Na 2 CO 3 = mol Na 2 CO g NaNO 3 2 mol NaNO 3 b. If 7.50 g of Na 2 CO 3 reacts, how many moles of CO 2 are produced? 7.5 g Na 2 CO 3 x 1 mol Na 2 CO 3 x 1 mol CO 2 = mol CO g Na 2 CO 3 1 mol Na 2 CO 3 2

3 Sample Problem (mass-mass) Methane burns in air by the following reaction: CH 4 (g) + _2_O 2 CO 2 (g) + _2_H 2 O (g) What do you know? (What are the facts?) The mass of methane in grams 500 g CH 4 (Molar mass = 16 g ) Where are you going? (What is the unknown?) The mass of water produced unknown (Molar Mass = 18 g ) How do you get there? (conversion factor set-up) What steps are needed to calculate the mass of H 2 O produced from the burning of 500g of CH 4? 500 g CH 4 x 1 mol CH 4 x 2 mol H 2 O x 18 g H 2 O = 1125 g H 2 O 1 16 g CH 4 1 mol CH 4 1 mol H 2 O Does it make sense? yes 3

4 Practice Problems (Mixed Stoichiometry) To tell which equation process to use, look to the units on your fact and unknown. If your fact is in grams (mass) and the unknown is to be moles, then it is a mass to mole problem. If your fact is in mole, and the unknown is to be mole, then it is a mole to mole problem. Again, your units will let you know which process to use. 1. Ammonium hydrogen phosphate, (NH 4 ) 2 HPO 4, a common fertilizer, is made from reacting phosphoric acid, H 3 PO 4, with ammonia, NH 3. H 3 PO NH 3 (NH 4 ) 2 HPO 4 a. If 10.0 g of ammonia react, how many moles of fertilizer will be produced? (mass-mol) 10 g NH 3 x 1 mol NH 3 x 1 mol (NH 4 ) 2 HPO 4 = 0.29 mol (NH 4 ) 2 HPO g NH 3 2 mol NH 3 b. What mass of ammonia will react with 2800 kg of H 3 PO 4? (hint: convert kg to g) (mass-mass) 2800 kg H 3 PO 4 x 1000 g x 1 mol H 3 PO 4 x 2 mol NH 3 x 17 g NH 3 = 9.71x10 5 g NH kg 98 g H 3 PO 4 1 mol H 3 PO 4 1 mol NH 3 2. The following reaction shows the synthesis of zinc citrate, and ingredient in toothpaste, from zinc carbonate and citric acid. _3_ZnCO 3 + _2_C 6 H 8 O 7 (aq) Zn 3 (C 6 H 5 O 7 ) 2 (aq)+ _3_H 2 O(l)+ _3_CO 2 (g) a. How many moles of ZnCO 3 and C 6 H 8 O 7 are required to produce 30.0 mol of Zn 3 (C 6 H 5 O 7 ) 2? (mol-mol) (1) 30 mol Zn 3 (C 6 H 5 O 7 ) 2 x 3 mol ZnCO 3 = 90 mol ZnCO mol Zn 3 (C 6 H 5 O 7 ) 2 (2) 30 mol Zn 3 (C 6 H 5 O 7 ) 2 x _2 mol C 6 H 8 O 7 = 60 mol C 6 H 8 O mol Zn 3 (C 6 H 5 O 7 ) 2 (mol-mass)b. What quantities, in kilograms, of H 2 O and CO 2 are produced by the reaction of 500 mol of citric acid? (hint: answer calculates to grams, then convert to kg.) (1) 500 mol C 6 H 8 O 7 x 3 mol H 2 O x 18 g H 2 O x 1 kg = 13.5 kg H 2 O 1 2 mol C 6 H 8 O 7 1 mol H 2 O 1000 g (2) 500 mol C 6 H 8 O 7 x 3 mol CO 2 x 44 g CO 2 x 1 kg = 33 kg CO mol C 6 H 8 O 7 1 mol CO g 4

5 Source: Team 3, ICLCS Project, UIUC, ; IL State Stds: 11.A.4d; 11.5d; 12.C.5a 5

Stoichiometry. What is the atomic mass for carbon? For zinc?

Stoichiometry. What is the atomic mass for carbon? For zinc? Stoichiometry Atomic Mass (atomic weight) Atoms are so small, it is difficult to discuss how much they weigh in grams We use atomic mass units an atomic mass unit (AMU) is one twelfth the mass of the catbon-12

More information

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 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

More information

Problem Solving. Stoichiometry of Gases

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.

More information

Name Date Class STOICHIOMETRY. SECTION 12.1 THE ARITHMETIC OF EQUATIONS (pages 353 358)

Name Date Class STOICHIOMETRY. SECTION 12.1 THE ARITHMETIC OF EQUATIONS (pages 353 358) Name Date Class 1 STOICHIOMETRY SECTION 1.1 THE ARITHMETIC OF EQUATIONS (pages 353 358) This section explains how to calculate the amount of reactants required or product formed in a nonchemical process.

More information

Stoichiometry Review

Stoichiometry Review Stoichiometry Review There are 20 problems in this review set. Answers, including problem set-up, can be found in the second half of this document. 1. N 2 (g) + 3H 2 (g) --------> 2NH 3 (g) a. nitrogen

More information

Unit 9 Stoichiometry Notes (The Mole Continues)

Unit 9 Stoichiometry Notes (The Mole Continues) Unit 9 Stoichiometry Notes (The Mole Continues) is a big word for a process that chemist s use to calculate amounts in reactions. It makes use of the coefficient ratio set up by balanced reaction equations

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

Unit 10A Stoichiometry Notes

Unit 10A Stoichiometry Notes Unit 10A Stoichiometry Notes Stoichiometry is a big word for a process that chemist s use to calculate amounts in reactions. It makes use of the coefficient ratio set up by balanced reaction equations

More information

Name Class Date. Section: Calculating Quantities in Reactions. Complete each statement below by writing the correct term or phrase.

Name Class Date. Section: Calculating Quantities in Reactions. Complete each statement below by writing the correct term or phrase. Skills Worksheet Concept Review Section: Calculating Quantities in Reactions Complete each statement below by writing the correct term or phrase. 1. All stoichiometric calculations involving equations

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

Chemistry: Chemical Equations

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,

More information

CHEMICAL REACTIONS AND REACTING MASSES AND VOLUMES

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

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

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

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

More information

Acid-Base Titrations. Setup for a Typical Titration. Titration 1

Acid-Base Titrations. Setup for a Typical Titration. Titration 1 Titration 1 Acid-Base Titrations Molarities of acidic and basic solutions can be used to convert back and forth between moles of solutes and volumes of their solutions, but how are the molarities of these

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

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

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

More information

Chemical Proportions in Compounds

Chemical Proportions in Compounds Chapter 6 Chemical Proportions in Compounds Solutions for Practice Problems Student Textbook page 201 1. Problem A sample of a compound is analyzed and found to contain 0.90 g of calcium and 1.60 g of

More information

11-1 Stoichiometry. Represents

11-1 Stoichiometry. Represents 11-1 Stoichiometry What is stoichiometry? Calculations that relate the quantities of substances. It is the study of quantitative (measurable amounts) relationships in chemical reactions and equations.

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

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

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

More information

neutrons are present?

neutrons are present? AP Chem Summer Assignment Worksheet #1 Atomic Structure 1. a) For the ion 39 K +, state how many electrons, how many protons, and how many 19 neutrons are present? b) Which of these particles has the smallest

More information

Chemical Equations & Stoichiometry

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

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

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 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

More information

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.

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

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

2. The percent yield is the maximum amount of product that can be produced from the given amount of limiting reactant.

2. The percent yield is the maximum amount of product that can be produced from the given amount of limiting reactant. UNIT 6 stoichiometry practice test True/False Indicate whether the statement is true or false. moles F 1. The mole ratio is a comparison of how many grams of one substance are required to participate in

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

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

Stoichiometry. 1. The total number of moles represented by 20 grams of calcium carbonate is (1) 1; (2) 2; (3) 0.1; (4) 0.2.

Stoichiometry. 1. The total number of moles represented by 20 grams of calcium carbonate is (1) 1; (2) 2; (3) 0.1; (4) 0.2. Stoichiometry 1 The total number of moles represented by 20 grams of calcium carbonate is (1) 1; (2) 2; (3) 01; (4) 02 2 A 44 gram sample of a hydrate was heated until the water of hydration was driven

More information

Problem Solving. Percentage Yield

Problem Solving. Percentage Yield Skills Worksheet Problem Solving Percentage Yield Although we can write perfectly balanced equations to represent perfect reactions, the reactions themselves are often not perfect. A reaction does not

More information

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

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

More information

Sample Problem: STOICHIOMETRY and percent yield calculations. How much H 2 O will be formed if 454 g of. decomposes? NH 4 NO 3 N 2 O + 2 H 2 O

Sample Problem: STOICHIOMETRY and percent yield calculations. How much H 2 O will be formed if 454 g of. decomposes? NH 4 NO 3 N 2 O + 2 H 2 O STOICHIOMETRY and percent yield calculations 1 Steps for solving Stoichiometric Problems 2 Step 1 Write the balanced equation for the reaction. Step 2 Identify your known and unknown quantities. Step 3

More information

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

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

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

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

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

CHEMISTRY COMPUTING FORMULA MASS WORKSHEET

CHEMISTRY COMPUTING FORMULA MASS WORKSHEET CHEMISTRY COMPUTING FORMULA MASS WORKSHEET Directions: Find the formula mass of the following compounds. Round atomic masses to the tenth of a decimal place. Place your final answer in the FORMULA MASS

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

The Mole and Molar Mass

The Mole and Molar Mass The Mole and Molar Mass 1 Molar mass is the mass of one mole of a substance. Molar mass is numerically equal to atomic mass, molecular mass, or formula mass. However the units of molar mass are g/mol.

More information

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

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

More information

Unit 2: Quantities in Chemistry

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

More information

Chapter 8 How to Do Chemical Calculations

Chapter 8 How to Do Chemical Calculations Chapter 8 How to Do Chemical Calculations Chemistry is both a qualitative and a quantitative science. In the laboratory, it is important to be able to measure quantities of chemical substances and, as

More information

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

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,

More information

Formulae, stoichiometry and the mole concept

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

More information

Appendix D. Reaction Stoichiometry D.1 INTRODUCTION

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

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

6) Which compound is manufactured in larger quantities in the U.S. than any other industrial chemical?

6) Which compound is manufactured in larger quantities in the U.S. than any other industrial chemical? MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Which statement concerning Arrhenius acid-base theory is not correct? A) Acid-base reactions must

More information

4.3 Reaction Stoichiometry

4.3 Reaction Stoichiometry 196 Chapter 4 Stoichiometry of Chemical Reactions 4.3 Reaction Stoichiometry By the end of this section, you will be able to: Explain the concept of stoichiometry as it pertains to chemical reactions Use

More information

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Chapter 10 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) A gas at a pressure of 10.0 Pa exerts a force of N on an area of 5.5 m2. A) 1.8 B) 0.55

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

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

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

Liquid phase. Balance equation Moles A Stoic. coefficient. Aqueous phase

Liquid phase. Balance equation Moles A Stoic. coefficient. Aqueous phase STOICHIOMETRY Objective The purpose of this exercise is to give you some practice on some Stoichiometry calculations. Discussion The molecular mass of a compound is the sum of the atomic masses of all

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

Atomic Masses. Chapter 3. Stoichiometry. Chemical Stoichiometry. Mass and Moles of a Substance. Average Atomic Mass

Atomic Masses. Chapter 3. Stoichiometry. Chemical Stoichiometry. Mass and Moles of a Substance. Average Atomic Mass Atomic Masses Chapter 3 Stoichiometry 1 atomic mass unit (amu) = 1/12 of the mass of a 12 C atom so one 12 C atom has a mass of 12 amu (exact number). From mass spectrometry: 13 C/ 12 C = 1.0836129 amu

More information

IB Chemistry. DP Chemistry Review

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

More information

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

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

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

Chemical Calculations: Formula Masses, Moles, and Chemical Equations

Chemical Calculations: Formula Masses, Moles, and Chemical Equations Chemical Calculations: Formula Masses, Moles, and Chemical Equations Atomic Mass & Formula Mass Recall from Chapter Three that the average mass of an atom of a given element can be found on the periodic

More information

Name period Unit 9: acid/base equilibrium

Name period Unit 9: acid/base equilibrium Name period Unit 9: acid/base equilibrium 1. What is the difference between the Arrhenius and the BronstedLowry definition of an acid? Arrhenious acids give H + in water BronstedLowry acids are proton

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

Problem Solving. Percentage Composition

Problem Solving. Percentage Composition Skills Worksheet Problem Solving Percentage Composition Suppose you are working in an industrial laboratory. Your supervisor gives you a bottle containing a white crystalline compound and asks you to determine

More information

We know from the information given that we have an equal mass of each compound, but no real numbers to plug in and find moles. So what can we do?

We know from the information given that we have an equal mass of each compound, but no real numbers to plug in and find moles. So what can we do? How do we figure this out? We know that: 1) the number of oxygen atoms can be found by using Avogadro s number, if we know the moles of oxygen atoms; 2) the number of moles of oxygen atoms can be found

More information

Temperature. Number of moles. Constant Terms. Pressure. Answers Additional Questions 12.1

Temperature. Number of moles. Constant Terms. Pressure. Answers Additional Questions 12.1 Answers Additional Questions 12.1 1. A gas collected over water has a total pressure equal to the pressure of the dry gas plus the pressure of the water vapor. If the partial pressure of water at 25.0

More information

Concentration of a solution

Concentration of a solution Revision of calculations Stoichiometric calculations Osmotic pressure and osmolarity MUDr. Jan Pláteník, PhD Concentration of a solution mass concentration: grams of substance per litre of solution molar

More information

Unit 3 Notepack Chapter 7 Chemical Quantities Qualifier for Test

Unit 3 Notepack Chapter 7 Chemical Quantities Qualifier for Test Unit 3 Notepack Chapter 7 Chemical Quantities Qualifier for Test NAME Section 7.1 The Mole: A Measurement of Matter A. What is a mole? 1. Chemistry is a quantitative science. What does this term mean?

More information

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 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:

More information

CHEM 120 Online: Chapter 6 Sample problems Date: 2. Which of the following compounds has the largest formula mass? A) H2O B) NH3 C) CO D) BeH2

CHEM 120 Online: Chapter 6 Sample problems Date: 2. Which of the following compounds has the largest formula mass? A) H2O B) NH3 C) CO D) BeH2 CHEM 120 Online: Chapter 6 Sample problems Date: 1. To determine the formula mass of a compound you should A) add up the atomic masses of all the atoms present. B) add up the atomic masses of all the atoms

More information

Stoichiometry. 1. The total number of moles represented by 20 grams of calcium carbonate is (1) 1; (2) 2; (3) 0.1; (4) 0.2.

Stoichiometry. 1. The total number of moles represented by 20 grams of calcium carbonate is (1) 1; (2) 2; (3) 0.1; (4) 0.2. Stoichiometry 1 The total number of moles represented by 20 grams of calcium carbonate is (1) 1; (2) 2; (3) 01; (4) 02 2 A 44 gram sample of a hydrate was heated until the water of hydration was driven

More information

WRITING CHEMICAL FORMULA

WRITING CHEMICAL FORMULA WRITING CHEMICAL FORMULA For ionic compounds, the chemical formula must be worked out. You will no longer have the list of ions in the exam (like at GCSE). Instead you must learn some and work out others.

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

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

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

Chapter 8: Quantities in Chemical Reactions

Chapter 8: Quantities in Chemical Reactions Ch 8 Page 1 Chapter 8: Quantities in Chemical Reactions Stoichiometry: the numerical relationship between chemical quantities in a balanced chemical equation. Ex. 4NH 3 + 5O 2 4NO + 6H 2 O The reaction

More information

Chemistry Ch 15 (Solutions) Study Guide Introduction

Chemistry Ch 15 (Solutions) Study Guide Introduction Chemistry Ch 15 (Solutions) Study Guide Introduction Name: Note: a word marked (?) is a vocabulary word you should know the meaning of. A homogeneous (?) mixture, or, is a mixture in which the individual

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

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

Enthalpy of Reaction and Calorimetry worksheet

Enthalpy of Reaction and Calorimetry worksheet Enthalpy of Reaction and Calorimetry worksheet 1. Calcium carbonate decomposes at high temperature to form carbon dioxide and calcium oxide, calculate the enthalpy of reaction. CaCO 3 CO 2 + CaO 2. Carbon

More information

Molecules, Atoms, Grams and Mole Calculation Practice

Molecules, Atoms, Grams and Mole Calculation Practice Molecules, Atoms, Grams and Mole Calculation Practice Helpful HINTS: In these problems look for two things: 1) From what unit to what unit? 2) Does the object stay the same, or does the object change?

More information

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

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

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

Balancing Chemical Equations Worksheet

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.

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

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

Exercise 3.5 - Naming Binary Covalent Compounds:

Exercise 3.5 - Naming Binary Covalent Compounds: Chapter Exercise Key 1 Chapter Exercise Key Exercise.1 Classifying Compounds: Classify each of the following substances as either a molecular compound or an ionic compound. a. formaldehyde, CH 2 O (used

More information

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

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

More information

Chemistry B11 Chapter 4 Chemical reactions

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

More information

Sample Exercise 3.1 Interpreting and Balancing Chemical Equations

Sample Exercise 3.1 Interpreting and Balancing Chemical Equations Sample Exercise 3.1 Interpreting and Balancing Chemical Equations The following diagram represents a chemical reaction in which the red spheres are oxygen atoms and the blue spheres are nitrogen atoms.

More information

Chemistry 12 Worksheet 1-1 - Measuring Reaction Rates

Chemistry 12 Worksheet 1-1 - Measuring Reaction Rates Chemistry 12 Worksheet 1-1 - Measuring Reaction Rates 1. A chemist wishes to determine the rate of reaction of zinc with hydrochloric acid. The equation for the reaction is: Zn (s) + 2HCl (aq) oh 2(g)

More information

87 16 70 20 58 24 44 32 35 40 29 48 (a) graph Y versus X (b) graph Y versus 1/X

87 16 70 20 58 24 44 32 35 40 29 48 (a) graph Y versus X (b) graph Y versus 1/X HOMEWORK 5A Barometer; Boyle s Law 1. The pressure of the first two gases below is determined with a manometer that is filled with mercury (density = 13.6 g/ml). The pressure of the last two gases below

More information

A dozen. Molar Mass. Mass of atoms

A dozen. Molar Mass. Mass of atoms A dozen Molar Mass Science 10 is a number of objects. A dozen eggs, a dozen cars, and a dozen people are all 12 objects. But a dozen cars has a much greater mass than a dozen eggs because the mass of each

More information

Balancing Chemical Equations

Balancing Chemical Equations Why? Balancing Chemical Equations Atoms are neither created nor destroyed in a chemical reaction, they are just rearranged. In other words, in a chemical reaction, what goes into the reaction must come

More information

CHM1 Review for Exam 12

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

More information

UNIT (6) ACIDS AND BASES

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

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

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

Chapter 8: Chemical Equations and Reactions

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

More information

Chapter 6 Notes. Chemical Composition

Chapter 6 Notes. Chemical Composition Chapter 6 Notes Chemical Composition Section 6.1: Counting By Weighing We can weigh a large number of the objects and find the average mass. Once we know the average mass we can equate that to any number

More information