Catalyst 1.What does the Latin root exo- mean? 2.What does the Latin root endo- mean? End

Justify – TPS In your opinion, which character would be exothermic? Which character would be endothermic?

Lecture 7.1 – Endothermic and Exothermic Reactions

Today’s Learning Targets 7.1 – I can describe how the motion of molecules relates to temperature. 7.2 – I can compare and contrast the ideas of an exothermic reaction and an endothermic reaction.

Today’s Focus Question Does the breakdown of Flamin’ Hot Cheetos require energy or release energy?

What are endothermic and exothermic reactions?

I. Heat and Temperature Heat is the transfer of energy between substances due to a difference in temperature Faster a substance moves = higher temperature

II. Exothermic Reactions An exothermic reaction is one that releases energy during the reaction Energy listed as a product in the equation Reactants  Products + Energy

III. Endothermic Reactions An endothermic reaction that requires energy during the reaction Energy listed as a reactant in the equation Energy + Reactants  Products

Class Example Is the following reaction endothermic or exothermic? NH 4 NO kJ/mol  HNO 3 + NH 3

Table Talk Is the following reaction endo- or exothermic? 2H 2 + O 2 → 2H 2 O kJ/mol

How are phase changes endothermic or exothermic?

I. Endothermic Phase Changes Absorbs Energy

II. Exothermic Phase Changes Release Energy

Class Example I have a pot of water and I heat it up until it turns into gas. Is this an endothermic or exothermic process?

Table Talk You have a test tube where you run the reaction. If the test tube is hot following the reaction, then is this endothermic or exothermic?

Summarize

White Board Problems

1. The reaction container feels “hot” kJ + 2H 2 + O 2 → 2H 2 O 3. Bromine goes from a gas to a liquid 4. Water goes from a solid to a liquid 5. HCl + NaOH  H 2 O + NaCl kJ kJ + HNO 3 + KOH  H 2 O + KNO 3 7. Iodine goes from a liquid to a gas

Work Time Complete the worksheet with your table.

Exit Ticket Identify the following reactions as endothermic or exothermic: 1. Ca(OH) 2 + 2HCl  CaCl 2 + 2H 2 O kJ 2. The reaction container “feels cold” 3. Water going from solid to liquid.

Closing Time Worksheet 7.1 due Thursday/Friday