Thermochemistry 1 January 28 & 29, 2013 Ms. Boon Chemistry

Catalyst Catalyst: Review your grade report. List the standards in which you have earned a 3 or 4. List the standards in which you have earned a 1 or 2. Did you do your homework during the acids/bases unit? How much time did you spend studying for the acid/base exam? Did you complete the pH foldable worksheet (all sides) so that you had as much information as possible going into the exam? What will help you do even better next time? Catalyst: Review your grade report. List the standards in which you have earned a 3 or 4. List the standards in which you have earned a 1 or 2. Did you do your homework during the acids/bases unit? How much time did you spend studying for the acid/base exam? Did you complete the pH foldable worksheet (all sides) so that you had as much information as possible going into the exam? What will help you do even better next time?  Objectives  I can describe temperature and heat flow in terms of the motion of molecules or atoms  I can categorize chemical reactions and phase changes as exothermic or endothermic.  Objectives  I can describe temperature and heat flow in terms of the motion of molecules or atoms  I can categorize chemical reactions and phase changes as exothermic or endothermic.  Agenda  Catalyst  Unit 8 Vocabulary Practice  Notes: Thermochemistry  Practice: Exothermic vs. Endothermic  Agenda  Catalyst  Unit 8 Vocabulary Practice  Notes: Thermochemistry  Practice: Exothermic vs. Endothermic  Take out your flashcards please. Tonight’s HW: pp ; pp. 45 # 1-5, 11, 13

Shout Outs! Period 3: 3 or 4 on all standards: Douglas, Chris, Billy, Michael 3 or 4 on 4/5 standards: Jeric & Irma Out of 27 students who have taken the test, 6 scored proficient or advanced: 22% proficiency

Shout Outs! Period 5: 3 or 4 on all standards: Brian M., Jonathan, Raven, Xochilt 3 or 4 on 4/5 standards: Cristian, Victor, Surmani Out of 28 students who have taken the test, 7 scored proficient or advanced: 25% proficiency

Shout Outs! Period 2: 3 or 4 on all standards: Tania, Rumaldo, Zamir, Christian 3 or 4 on 4/5 standards: Susan, Erick, Saydy, Rudy, Denise Out of 23 students who have taken the test, 9 scored proficient or advanced: 39% proficiency

Shout Outs! Period 4: 3 or 4 on all standards: Leslie, Kieman, Patrick, Abel, Antonio, Luis, Briceida 3 or 4 on 4/5 standards: Ilsse, Richard Out of 24 students who have taken the test, 9 scored proficient or advanced: 38% proficiency

Shout Outs! Period 6: 3 or 4 on all standards: Kathy A., Juan, Kimberly, Christine 3 or 4 on 4/5 standards: Karim, Kevin, Jahmia, Deya, Sabrina, Sereno Out of 22 students who have taken the test, 10 scored proficient or advanced: 45% proficiency

Unit 8 Introduction Videos ce/matter/energy-and-matter.htm ce/matter/energy-and-matter.htm ce/energy-light-sound/heat.htm ce/energy-light-sound/heat.htm ce/matter/changes-of-matter.htm ce/matter/changes-of-matter.htm ce/matter/solids-liquids-gases.htm ce/matter/solids-liquids-gases.htm &CategoryID=2497

Unit 8 Vocabulary Practice Your partner for this activity is the person sitting next to you. Materials: – Each pair needs a white board, flashcards, and marker. Rules: – I will post a question on the board and you will use your flashcards to answer on the whiteboard. – Hold the whiteboard up when time is up.

Question 1 What is the difference between heat and temperature? Answer: – Temperature is a measure of the average kinetic energy of the particles in an object. Heat is the energy transferred between objects because of their different temperatures. Next Question: List the names of phase changes from solid to liquid and from liquid to gas.

Question 2 List the names of phase changes from solid to liquid and from liquid to gas. Answer: – Solid to liquid: melting or fusion – Liquid to gas: evaporation or vaporization Next Question: List the names of phase changes from gas to liquid and from liquid to solid.

Question 3 List the names of phase changes from gas to liquid and from liquid to solid. Answer: – gas to liquid: condensation – Liquid to solid: freezing Next Question: Draw a picture of the particles in a substance as a solid, liquid, and gas. Which has the highest temperature? How do you know?

Question 4 Draw a picture of the particles in a substance as a solid, liquid, and gas. Which has the highest temperature? How do you know? Answer: The gas has the highest temperature because the particles are moving the fastest. Next Question: What are the two units of temperature we use in chemistry? What are the two units for measuring heat & energy?

Question 5 What are the two units of temperature we use in chemistry? What are the two units for measuring heat & energy? Answer: – We use Celsius and Kelvin to measure temperature. – We use joules and calories for measuring heat and energy. That was the last question. Next up: Notes

Notes: Thermodynamics Thermodynamics is the branch of science concerned with the energy changes that accompany chemical and physical changes. In this unit, we will study how energy is transferred as heat in both chemical reactions and physical phase changes.

Heat is the energy that transfers from one object to another due to a difference in temperature. Heat flows from HIGH to LOW temperatures

Endothermic vs. Exothermic Energy transfers can be categorized as either endothermic or exothermic. EndothermicExothermic In an endothermic process, energy is absorbed. Example: cold pack NH 4 NO 3 (s) + H 2 O(l) + energy  NH 4 NO 3 (aq) Why does the cold pack feel cold? In an exothermic process, energy is released. Example: Hand warmer 4Fe(s) + 3O 2 (g)  2Fe 2 O 3 (s) + energy Why does the hand warmer feel hot? The energy absorbed as heat from the surroundings makes it feel cold. The energy released as heat to the surroundings makes it feel hot.

Endothermic vs. Exothermic EndothermicExothermic Example chemical reaction equations: NaCl(s) + H 2 O(l) + energy  NaCl(aq) Li 2 O + H 2 O kJ/mol → 2 LiOH Reaction Diagram Example chemical reaction equations: KBr(aq) + AgNO 3  AgBr(s) + KNO 3 (aq) + energy 1 H 3 PO HCl → 1 PCl H 2 O kJ/mol Reaction Diagram

Endothermic vs. Exothermic EndothermicExothermic Heat flow: Heat flows into the system from the surroundings. Example: Putting a cold pack on your elbow: heat flows into the cold pack. Heat flow: Heat flows out of the system into the surroundings. Examples: A campfire burning: heat flows out of the campfire.

Practice Draw a picture for each of the following scenarios. Clearly label the system and surroundings for each picture. Draw an arrow in the direction of heat flow. Label the Reaction as Endo or Exothermic System: The egg Surroundings: The pan, stove, etc. Heat flows: Into the egg -- Endothermic

More Scenarios Make a poster illustrating heat flow in one of the following scenarios, or make your own! Melting an ice cube Making Ice cream Boiling water to make Ma n’ Cheese The potential energy in a bond between two atoms is released Mixing Calcium Chloride in water feels warm Iron Rusting in acid releasing steam Mixing baking soda in water drops the temperature slightly Mixing water with acid feels hot Condensing steam into liquid water Combustion of octane gas in a car’s engine Breaking a bond between 2 atoms during digestion takes energy Sweat evaporating off an athlete’s skin Cooking an egg Putting a cold pack on your knee Wood burning in a fireplace A lake freezing in the winter