LARN 138 C35D2

LARN 138 C35D2

Start the following in class:

1.  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, J138A, for today is

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).

a. Compare and contrast the terms enthalpy of fusion (a.k.a. heat of fusion) and an enthalpy of solidification (a.k.a. heat of solidification).

b. Compare and contrast the terms enthalpy of vaporization (a.k.a. heat of vaporization) and an enthalpy of condensation (a.k.a. heat of condensation).

c. Compare and contrast the terms enthalpy of reaction (a.k.a. heat of reaction) and an enthalpy of solution (a.k.a. heat of solution).

1.b. The second required focus topic, J138B, for today is

Examine Figure 17.10 on page 523 of the text which shows how the temperature of a sample of water that is being heated changes as time progresses.

1. What is happening to the water in those places on the graph where the temperature of the water is not rising, even though the water is being heated?
2.  Why does the temperature of the water go up most of the time when the ice, liquid water, or water vapor is heated?
3. When the ice, liquid water, and steam are increasing in temperature, how is the thermal energy being transferred into the water being stored?
4. What mathematical formula might be used to calculate the amount of energy being absorbed by the ice, liquid water, or steam when the waters temperature is rising?
5. Is the specific heat capacity of ice, liquid water, and steam the same? Give the reasoning in support of your response.
6. Why doesn’t the temperature of the water increase when the water is melting or boiling?
7. When the ice is melting and when the water is boiling, how is the thermal energy being transferred into the ice being stored?
8. What mathematical formula might be used to calculate the amount of energy being absorbed by the ice when the water’s temperature is not rising because the ice is changing into liquid water?
9. What mathematical formula might be used to calculate the amount of energy being absorbed by the liquid water when the water’s temperature is not rising because the liquid water is changing into steam?
10. Again look at Figure 17.10 on page 523 of the text.  Tell when each of the following formulas might be used to solve a problem involving the transfer of thermal energy.

1) Use q = ΔH_fus when …

2) Use q = m_ice · C_{p ice} · T_ice when …

3) Use q = ΔH_vap when …

4) Use q = m_steam · C_{p steam} · T_steam when …

5) Use q = m_water · C_pwater  · T_water when … 

2.a. Use the PQ5R or SQ5R method to prepare study guide for text section 17.3 on Heat in Changes of State or go to https://socratic.org/chemistry  to research the topics brought up in section 17.3 of your text.  Read section 17.3 in your chemistry text, pages 520 through 526 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.

Use dimensional analysis and the molar heat of fusion conversion ratio to help set up the next two problems.

• Include the units of each measured quantity, cancel all units that are both in a numerator and a denominator of multiplied ratios, and label the resulting units of each calculated value. Also circle and express the calculated result to the proper number of significant figures.
• Study Sample Problem 17.4 on page 521 and then show your work including all conversion ratios for practice problems I17-21 (In chapter 17, problem 21) and I17-22.

Use dimensional analysis and the molar heat of vaporization conversion ratio to help set up the next two problems.

• Include the units of each measured quantity, cancel all units that are both in a numerator and a denominator of multiplied ratios, and label the resulting units of each calculated value. Also circle and express the calculated result to the proper number of significant figures.
• Study Sample Problem 17.5 on page 524 and then show your work including all conversion ratios for practice problems I17-23 (In chapter 17, problem 23) and I17-24.

Use dimensional analysis and the molar heat of solution conversion ratio to help set up the next two problems.

• Include the units of each measured quantity, cancel all units that are both in a numerator and a denominator of multiplied ratios, and label the resulting units of each calculated value. Also circle and express the calculated result to the proper number of significant figures.
• Study Sample Problem 17.6 on page 526 and then show your work including all conversion ratios for practice problems I17-25 (In chapter 17, problem 25) and I17-26.

In the Section Assessment 17.3 on page 526, read, analyze, describe and explain practice problems I17-27 (In chapter 17, problem 27), I17-28, I17-29, I17-30abcde and I17-30a b c d e, and I17-31.

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. Review those concepts that we have discussed in class that are in your study guides, that are in your text study guide at the end of the chapter, and that on the chapter vocabulary sheet provided to you that describes what is a substance, an element, a compound, a coarse mixture, a colloidal suspension, a solution; an atom; a formula unit, a molecule;a phase, an aqueous phase; a chemical change,a physical change;a chemical reaction, a reactant, a product, a word equation, and a formula unit equation;and how are these concepts different?  You need to be able to explain the meaning of each of these terms, and be able to differentiate the terms, be able to compare and contrast these related terms, and give examples that make clear the points that you are trying to  explain.  Go over each of these concepts with your study partner.

2. 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?

3. Think about the fifteen 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.