LARN 139 C35D3

LARN 139 C35D3

Start the following in class:

1.a.  Write your journal entry on sheets of three holed 8.5 inch by 11 inch ruled paper in your Journal notebook. In the upper right corner white space of each upward facing page, write your hand in number within a circle followed by your name. Each journal entry should either be at least a paragraph of exemplary writing and penmanship concerning a single topic, or be a concept map relating chemistry terms. Begin each day’s paragraph with a topic sentence, follow with explained instances, and close with a focused summary statement.

The required focus topic, J139A,  for today is

1. Compare and contrast the concepts of heat and temperature as they are used in chemistry.
2. Examine and study Figure 17.10 on page 523 of your text.  Note that as thermal energy is added to a substance and the substance absorbs that energy,sometimes the temperature of the substance increases but at other times the temperature of the substance levels off as the substance changes phase [by melting, freezing, vaporizing, or condensing].

b1. What algebraic expression is used to calculate the amount of thermal energy absorbed when the substance’s temperature is increasing?   Give an example and in your learning journal and by explain how the example demonstrates the concept being considered.

b2. What algebraic expression is used to calculate the total amount of thermal energy absorbed per the mole of substance undergoing a phase change?  Give an example and in your learning journal and by explain how the example demonstrates the concept being considered.

1.b.  Though the text should be referred to, the goal of journaling is to deepen understanding by thinking and reflection, so do not paraphrase material out of the text that might not directly address the challenge at hand.

Recall:

• Enthapy is the term used in chemistry to designate the total energy (a.k.a. heat content) of a chemical system when the total pressure of any gases present in the system is not changing (a.k.a. the system is at constant pressure).
• A thermochemical equation is a chemical equation with a statement of the measured enthalpy change for the reaction as recorded in the balanced chemical expression being added to the right side of the chemical equation (after leaving a slight space to the right of the last products formula). The change in enthalpy for reactions that are too slow to observe or which do not readily occur as written in a balanced equation can be determined by using Hess’ law.  Hess’ law states that the enthalpy change for a multistep process is equal to the sum of all of the enthalpy changes for each individual step of the process.  Hess’ law thus states that the thermochemical equation for a target process is equal to the sum of any set of thermochemical equations that produce the thermochemical equation for the target process when added together.
• The standard state of a substance is a statement of the phase and formula for the way the substance exists at 25.0 C [298.15 K] and 101.325 kPa pressure.

The required focus topic, J139B,  for today is

a. Compare and contrast the concepts of thermal energy and temperature as they are used in chemistry.

b. Describe how Hess’ law follows logically from the principle of the conservation of energy in chemical processes.

2.a. Use the PQ5R or SQ5R method to prepare study guide for text section 17.4 on Calculating Heats of Reaction.  Read section 17.4 in your chemistry text, pages 527 through 533 and as you do, create a study guide using the SQ5R or PQ5R method explained in class and on the distributed handout packet. You may record vocabulary entries in the body of your study guide, or you may check them off on the chapter 17 vocabulary list that was distributed as you think about the meanings of the terms and add any notations to the vocabulary list for clarifications sake.

2.b.  After you have finished reading the assigned section of the chapter, answer the formative assessment questions and do some formative assessment problems to inform you about the degree of your comprehension and understanding.  Assessment questions are printed at the end of the section that you have just read.  Reflect on your answers to assure yourself that you have understood the major points in the section that you have just read.  Record your responses to questions that are challenging you, so that you can later review what you are learning.  If all problems seem easy to you, record the response to the problem that was least easy for you to answer.

Writing in blue or black ink, place your hand in number in a circle followed by your name in the upper right white space of a piece of three holed composition paper that hasn’t been written on.  Place the page reference for the problems to be considered to the left of the red marginal line on the first blue line.  Centered on the first blue line, write a descriptive title for the learning activity such as Section C1.4 Responses where C1.4 represents Chapter1.section4.  Before you write your response to each question or problem listed below, write its designation to the left of the red marginal line as listed below, followed by your response in ink to the right of the marginal line.

If solving the problem entails the use of multiplication or division, show your work by including a ? followed by the unit of the quantity you are solving for, an = sign, followed by the quantity given that has all or part of the dimensions of whatever quantity you are solving for, followed by mathematical operations on all labeled quantities, conversion ratios or comparison ratios that are used to obtain the sought for quantity.

• Study Conceptual Problem 17.7 on page 531.  Show your work for practice problem I17-32abc (In chapter 17, problem 32abc).
• Show your work, answer the question and explain your reasoning for practice problem I17-33ab.
• In the Section Assessment 17.4 on page 532, read, analyze, describe and explain practice problems I17-34 (In chapter 17, problem 34), and I17-36; and read, analyze, and show your work including all calculations involving values for changes in enthalpy for practice problems I17-35, and I17-37.
• After you have finished responding to the formative assessment questions and problems, check page R97 of the text and check each of those problems that you can by writing in either a check mark (√) or a correction in green ink.  Write down any question that you still have so that you can ask about it in class.  In the margin of your notebook page, circle the number of formative assessment questions do not have a suggested response given and check your response with that of your classmates when you come to class.

Recommended for those who have time left in their 45 minute study period, but not required of all:

1.  How do the properties of covalent molecular substances with hydrogen bonding typically differ from those covalent molecular substances that form molecules whose van der Waals attractive forces only weakly attract other molecules?

2.  Think about the sixteen properties of covalent molecular substances listed on the Properties to be understood worksheet describing differences in the properties of metals, ionic compounds, covalent network solids, and covalent molecular compounds.  Continue to study this handout for understanding and review how the typical properties of members of these classes of compounds depend on whether the compound has localized or delocalized electrons, and upon whether strong metallic, ionic, or covalent bonding or weak van der Waals forces of attraction are predominant between representative particles of the substances.  Try to understand how each property of a given covalent molecular substance is related to the groups of covalently bonded atoms that form molecules whose van der Waals attractive forces only weakly attract other molecules.

3. Continue to review the meanings of the words on the chapter 1, chapter 2, chapter 3, chapter 4, chapter 5, chapter 7, chapter 8, chapter 9, chapter 10, chapter 11, chapter 12, chapter 13, chapter 14, chapter 15, chapter 16, and chapter 17 vocabulary lists.  Place a – symbol in front of each word that you have to study more, and a change the- to a + symbol in front when you have demonstrated mastery over the word to a study buddy, parent, or friend.