Monday April 6th and Tuesday April 7th

• please read exothermic vs endothermic reactions
• please try enthalphy game (answers)
• please also try enthalphy game test questions

This concept can be very difficult.  There are easy questions and hard.  Endothermic means an increase in potential energy which means a + "Delta" H value (can't find the upside down triangle sign that is needed for "Delta"), - Q value, heat is aborbed could get cold or is at least preventing it form getting hot.  Exothermic is the opposite.  You will need to read through the note on heat and first law of thermodynamics to get a better sense of this.  Please look at the enthalphy game test questions to get a better sense of this.  The exothermic vs endothemic section in the thermodynamics summary has additional information.

VIDEO PART #1

VIDEO PART #2

NOTE 1,  NOTE 2,  NOTE 3,  NOTE 4

Friday April 3rd - Day 40

Thursday April 2nd - Day 39

Wednesday April 1st - Day 38

• carefully read through the Hess law and heat summation focusing on the Hess' Law section
• look through (step through process for question #2 from the Hess law questions)
• try as many questions from Hess law as you like and check your answers against what is show in the upper right of this page!

• review and learn how to do combination problems
• answers: 1,  2,  3,  4,  5,  6,  7,  8
• answers to 1 to 8 combined
• do more of the combination problems  and find the answer from the answers to tests by test number: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, bonus using the reference number show in red on the combination problems sheet

• work on some of combination problems
• answers: 1,  2,  3,  4,  5,  6,  7,  8
• answers to 1 to 8 combined
• pay very careful attention to the format and the parts for each problem
• the conversion factor sequence is often the most difficult
  • please see "METHODS OF CONVERTING" from the thermodynamics summary
  • once you have this figured out, you are well on your way!

• read through the second half of the Hess law and heat summation starting at the zero point energy section
• look carefully at the heat of formation values from pg 799 - THIS TABLE IS VERY IMPORTANT IN THIS UNIT AND SHOULD ALWAYS BE AVAILABLE AS A REFERENCE SOURCE
  • the column with the DH_f^o values is the importan column, the energy in kJ is a potential energy and can be used two different ways
  • represents the potential energy of the compound (using the element zero point reference)
  • represents the "heat of reaction" (a.k.a the change in enthalph a.k.a the change in chemical potential energy) for a FORMATION REACTION that produces the given compound
• please look at the third page of thermodynamics summary for key terminology
  • IN PARTICULAR FORMATION REACTION AND HEAT OF FORMATION
  • a formation reaction must have only one product and only one mole of that product (i.e. the stoichiometric coefficient in the balance chemical equation must be a "1")
  • a formation reaction can only have element reactants and fractional coefficients are allowed (improper fraction is preferred)
• the values from page 799 are used in the heat summation calculation from the Hess law and heat summation note - PLEASE LOOK THIS THROUGH CAREFULLY TO SEE HOW THE NUMBERS FROM 799 ARE USED
  • also please note that elements are give a 0 kJ value as per the choice of zero point (it is for this reason that they do not show up in the 799 table - this would be like adding 0 oxidation states to all elements on the periodic table - instead it is understood that an element in its natural state has 0 as an oxidation state and has been assigned 0 for its potential energy
• you could start on tomorrows work at this point, or you could think about this a bit more, the key ideas in this unit are here and worth figuring out

• go through note on the first law of thermodynamics slowly and carefully
• would like to give examples of two calculations similar to the first two question from thermodynamics worksheet #2
  • see these two calculations - answers 1,  2
  • please note the rigorous format
  • the first law of thermodynamics DH = - Q (the D should be a delta symbol) is an important part of this, heat is Q and is kinetic, DH is chemical potential energy
  • you could think of these problems as having a working with Q vs a working with DH sections with DH = -Q as the link between these sections
• work on question #1, 2 and 3 only from thermodynamics worksheet #2  - see above for answers

• review the note on heat
• complete thermodynamics worksheet #1 (answers)

• carefully read through the note on heat
• start working on thermodynamics worksheet #1 (answers) using answers to help formulate your thinking