Marking Period 3 Review Day 3 Unit 9, Mole Calculations Unit 10, Solutions

Schedule For the Week Day 1: Unit 7 - PE Diagrams and Equilibrium (Wednesday) Day 2: Unit 8 - Heat/Exo and Endo Reactions (Thursday) Day 3: Unit 9 - Mole Calculations and Unit 10 - Solutions (Friday) Day 4: Marking Period 3 Review Exam (Monday)

How are you graded? The packets for Day 1, 2, and 3 are worth 25 HW points each. The exam on Monday is an exam grade. On days 1, 2, and 3, the class will end with a short quiz on that day’s material. The class with the highest quiz average receives a reward the following day.

Answer key to day #2 Topic #1: summarize 1)Did during Do-Now…KE change = temp change; PE change = phase change a)MP = Liquid to solid = 50°C; BP = gas to liquid = 110°C b) KE decreases = AB, CD and EF c)PE decreases = BC and DE d)B Topic #2: entropy 1. S  L randomness increases (particles spread out) 2. L  S entropy decreases (particles closer together) Summarize: 1) EntRopy = Randomness Topic #3: enthalpy 1. enthalpy increases (energy a product = adding heat l  g Summarize: 1) EntHalpy = Heat

Unit 8 practice 1)3 minutes 2)5 minutes 3)B 4)110°C 5)C 6)20 kJ 7)15 kJ

Heat calc review

More practice! 1)Mcdt = 15 x 4.18 x 8 = J 2)mHf = 14.2 x 334 = J 3)mHv = 8.2 x 2260 = J 4)Mcdt = 109 g Not water 1)Mcdt = J 2)mHf = J 3)mHv = J 4)Mcdt = g

1. If Daniel dissolves 20g NaCl at 90  C in 100g H 2 O, is his solution saturated, unsaturated, or supersaturated? _____________________________ Explain: 2. If Laura dissolves 20g NaCl at 90  C in 100g H 2 O, how many more grams does he need to dissolve to make a saturated solution? _________________ g 3. Jaylene added 70 grams HCl to 100grams H 2 O at 70  C. How many grams of solid precipitate settled at the bottom of the container? _______________ g 4. Chris completely dissolved 100g KNO 3 in 100g H 2 O at 70  C. When the solution cooled to 10  C, how many grams of KNO 3 precipitated out of the solution (became a solid and sat at the bottom of the beaker) _____________ g 5. At 10  C, how many grams of SO 2 dissolves in…. a) 100 grams of H 2 O___________ g b) 200 grams of H 2 O___________ g c) 50 grams of H 2 O___________ g

Practice: 1. Which molecule is polar? (a) H 2 (b) CH 4 (c) H 2 O(d) Br 2 2. Which molecule is polar? (a) Cl 2 (b) I 2 (c) CO 2 (d) NH 3 3. Which molecule is non-polar? (a) HCl(b) H 2 O (c) F 2 (d) CH 4 4a. Explain, in terms of distribution of electrons, why H-H is non- polar. Answer: H-H is a polar bond because the atoms have equal electronegativities so the electrons are shared equally. 4b. Explain, in terms of distribution of electrons, why H-F is polar.

5a. Explain, in terms of electronegativity, why H-H is non-polar. Answer: H-H is a non-polar bond because both H atoms have the same electronegativity. 5b. Explain, in terms of electronegativity, why H-F is polar. 6. Explain, in terms of molecular polarity, why oils do not dissolve in water. (Your answer must include the polarity of both water and oil to receive credit) 7. An atom of which element has the weakest attraction for electrons in a covalent bond? (a)F(b) O (c) Na(d) Cl