This website uses cookies to ensure you have the best experience. Learn more

Lab Chapter 3 Essay

5125 words - 21 pages

CHAPTER 3
MASS RELATIONSHIPS IN CHEMICAL REACTIONS
This chapter reviews the mole concept, balancing chemical equations, and stoichiometry. The topics covered in this chapter are:
• Atomic mass and average atomic mass
• A vogadro’ s number, mole, and molar mass
• Percent composition calculations
• Empirical and molecular formula determinations
• Chemical equations, amount of reactant and product calculations
• Limiting reagents and reaction yield calculations
Take Note: It is absolutely essential that you master the mole concept to do well on the quantitative aspects of AP Chemistry!!
When solving quantitative problems on the Free Response section of the AP exam, supporting work ...view middle of the document...

00000 amu and 13.00335 amu, respectively.)
- 24 -
Solution to Example 1.
(12.00 amu × 0.9890) + (13.00335 amu × 0.0110) = 12.01 = average atomic mass of carbon
Molecular mass refers to the mass of a molecule expressed in atomic mass units. The molecular mass is the sum of the atomic masses of the atoms in the molecular formula.
Example 2. Determining molecular mass.
Determine the molecular mass of barium hydroxide, Ba(OH)2 .
Solution to Example 2.
1 Ba atom + 2 O atoms + 2 H atoms
137.33 amu + 2(16.00 amu) + 2(1.0079 amu) = 171.34 amu
Avogadro’s number, mole, and molar mass
Avogadro’s number refers to 6.022 × 1023 particles. The quantity of an element that contains Avogadro’s number of particles is called a mole. The molar mass of an element or compound is the mass of one mole of its atoms or molecules expressed in grams.
Some examples of mole, atom, ion, molecule, and mass equivalencies are: • 1moleofCatoms= 6.022×1023 atomsofC= 12.01gofC
• 1 mole of O2 molecules = 6.022 × 1023 molecules of O2 = 32.00 g O2
• 1 mole of of O2 molecules = 2 moles of oxygen atoms = 12.044 × 1023 atoms of O
• 1 mole O2– ions = 6.022 × 1023 O2– ions = 16.00 g O2– ions
Percent composition calculations
The percent composition of an element in a compound =
n × molar mass of element × 100% where molar mass of compound
n is the number of moles of the element in the compound
- 25 -
Example 3. Determining the percent composition.
Determine the percent composition of chloride in barium chloride, BaCl2.
Mass of 2 Cl ̄ × 100 = 2(35.45 g Cl ̄)_____
Mass of BaCl2 2(35.45 g Cl ̄) + 137.33 g Ba × 100% = 34.0 % Cl ̄
Empirical and molecular formula determinations
The empirical formula is the most reduced form of the molecular formula. For instance, sugar, which has the molecular formula of C6H12O6, has an empirical formula of CH2O. Empirical formulas can be determined from percent composition data. If the molar mass is also known, the molecular formula can be determined as well (see Example 4).
Example 4. Determining empirical and molecular formulas.
An unknown compound is known to contain 30.43% N and 60.56% O and has a molar mass of 92.00 g. What are the empirical formula and the molecular formula for the compound?
General Strategy
Solution to Example 4
Assume a 100 g sample.
30.43 g of N 60.56 g O
Convert gram quantities to moles by dividing by the molar mass of the atom.
30.43gN _ 14.01 g N/mol N
60.56 g O 16.00 g O/ mol O
= 2.17 mol N = 4.35 mol
Divide by the smallest number of moles to obtain whole number ratios. The whole number ratios are the subscripts in the empirical formula.
2.17 mol N 2.17 mol N
4.35 mol O 2.17 mol N
Empirical formula
= 1molN = 2mol
= NO2
To determine the molecular formula divide the molar mass by the empirical mass. Multiply the subscripts of the empirical formula by this factor.
Empirical mass of NO2 = 14.01 g N + 2(16.00) g O = 46.01 g NO2
Molar mass = 92.00 g = 2...

Other Papers Like Lab Chapter 3

Lab Final Essay

638 words - 3 pages ------------------------------------------------- Lab Final Unit 11 Lab Final: Voltage Regulator with Constant Current Limiting (PORTFOLIO) Scope and Intention of the Project: The Lab Final Project is a self-directed project with specific requirements provided. You will be given a design task which utilizes a standard circuit in the textbook. You will apply knowledge that has been acquired in lecture, assignments, and previous labs

Java Page Essay

4657 words - 19 pages ? —Psalms 42:5 ■ ■ © Copyright 1992-2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved. Chapter 10 Object-Oriented Programming: Polymorphism 307 Assignment Checklist Name: Section: Date: Exercises Assigned: Circle assignments Date Due Prelab Activities Matching Fill in the Blank Short Answer Programming Output Correct the Code YES YES YES YES YES YES 1 NO NO 1 YES NO NO NO NO NO NO Lab

Strand: the Nature of Science

730 words - 3 pages :: polen grain, polinitzation, ovule, stamente, pistil, ovary, germination. ï‚¡___ Section Focus Transparency 3, p. 68, TCR; Transparency Activity, p. 44, CRB, (ELL) ____ Reading Preview, p. 413, TWE ____ Interactive Chalkboard, Ch. 14, Sec. 3, TCH Journal/Essay Class work Quiz/ Test H. Learning Oral Resp Demonstration Laboratory Hands on__ MiniLAB: Modeling Seed Dispersal, p. 420; MiniLAB Worksheet, p. 4, T9, CRB, (ELL) __ LAB

Itt 255 Lab 6

3922 words - 16 pages 2 2 Application of Security Countermeasures to Mitigate Malicious Attacks Fundamentals of Information Systems Security:  Chapter 3  Chapter 4 Project 2.2 6 2.3 Assignment 2.4 1 1 3 Appropriate Access Controls for Systems, Applications, and Data Access Fundamentals of Information Systems Security:  Chapter 5 Lab 3.1 2 Discussion 3.2 4 Assignment 3.3 1 15 Date: 2/12/2012

Nt2580 Unit 1

3775 words - 16 pages NT2580-M1 Introduction to Information Security Unit 1: Information Systems Security Fundamentals 2015-Summer, 6/20/2015, Saturday (9:00am – 1:30pm) Student Name ___________________________________ Lesson Plan Theory (in class, Lab #2)……………………………..…………………..……...2 Reading  Kim and Solomon, Chapter 1: Information Systems Security. Objectives……………..………………….……………………………….2 Student Assignments for this Unit Unit 1 Lab Perform

Anything Relevant

4105 words - 17 pages | | | |In-class activity 2: Growth strategy | |3 |Lecture |Chapter 3: Analyzing the Marketing Environment | |(Jan 25-29) | | | | |Discussion

Business Amd Management

346 words - 2 pages to the factual numbers. The people in the focus groups did not believe that they could really kill more germs. Question 3 How did Unilever use qualitative and quantitative research (see Chapter 16) to develop the positioning claim for Lifebuoy? Answer: Unilever use the qualitative and quantitative research to develop a positioning claim. They use quantitative research by using the lab to prove that they killed more germs than competitors

Ge150

1675 words - 7 pages . Exercise 1 – Chapter 3 * When you rub your hands together vigorously, you feel the heat building up and in this process; you are converting kinetic energy into heat energy. * I would definitely purchase the one that is expensive to buy and cheaper to run because it will save me more money in the long haul and will also be more environmentally friendly and very energy efficient as well. Unit 2. Exercise 1 – Chapter 4 Discussion Questions

Nt1210 Chapter 1

1281 words - 6 pages . Chapter 1 review questions 1. Which of the following is true about 1 bit? d. Represents four binary digits 2. Which of the following terms means approximately 106 bytes? b. Megabyte 3. Which answer lists the correct number of bits associated with each term? b. 32 bits per word 4. Which of the following answers are true about random-access

Double Pipe Heat Exchanger

2578 words - 11 pages comparing test #3 to test #8, which has been brought to my attention by the teaching assistant for this lab as being a known issue for the laboratory’s experimental setup. This could be due to the turbulence experienced in the 90° bends of the lab setup or perhaps the length of the pipes that the temperatures are being measured at the beginning and end of perhaps not being long enough, there are many factors that may make the data appear as it has for

Lab1

765 words - 4 pages sections of the model. 3. Provide a comparison table showing the similarities and differences between desktop and notebook computers. Required Setup and Tools In this laboratory, students will need only paper and pencil to do the required work. However, the use of a drawing program, such as Visio or the Drawing toolbar in Microsoft Word, is suggested for drawing the von Neumann computer model. Lab Solutions The student should provide

Related Essays

Vulnerability Assessment Scan Essay

572 words - 3 pages ------------------------------------------------- Lab Assignment for Chapter 3 Performing a Vulnerability Assessment Course Name and Number: Student Name: Student Number: Instructor Name: Onook Oh Submission Due by: 11:59PM on February 3rd, 2015 ------------------------------------------------- Overview To complete the Lab Assignment for Chapter 3, students should first carefully read the “Introduction” information in the lab

It250 Week 9 Essay

1093 words - 5 pages following homework is designed to cover the course objectives for this unit. Assignment 9.1: Complete the following exercise in your textbook: * Chapter 16: Question 1-5 on page 643 Submit your written answer to your instructor at the start of Unit 10. Labs Instructor Notes: Assign students the following lab which can be printed from Appendix D. Lab 9.1: Using tar to Back Up Files What is the purpose? This lab exercise lets you

Work Ethics Essay

1791 words - 8 pages which the sub-departments within the lab can work together to form one strong core lab (a unit of one)? Hypothesis I predicted that if we can create a core lab, then we will be able to decrease our turnaround times and provide better patient care. Method Chapter 13 in our textbook written by Bateman and Snell, helped me formulate my idea. The chapter has a section called motivating for performances, and while reading it I decided that we needed

Management Information System Essay

713 words - 3 pages processes in the clinic? * What specific benefits does the institution stand to benefit from implementing the EMR? * The system should allow capturing of only the relevant data from patients. * Presentation (PP and Proposal) to include a flow chart diagram. CHAPTER 3: BUSINESS INFORMATION SYSTEMS The various business processes and activities can be done manually without using ICT. You have been contracted as an IT consultancy company