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74 Days Until the Final. What does the Latin root exo- mean? What does the Latin root endo- mean?. End. Today ’ s Learning Targets.
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74 Days Until the Final • What does the Latin root exo- mean? • What does the Latin root endo- mean? End
Today’s Learning Targets • 7.1 – I can describe how the motion of molecules relates to temperature. For example, if I have a hot solution and a cold solution, I can explain the motion in the molecules in each one of these solutions. • 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?
Review of Heat and Temperature • Heat is the transfer of energy between substances due to a difference in temperature • The faster a substance is moving the higher its temperature will be. • A substance at a high temperature has fast moving molecules and a substance at a low temperature has slow moving molecules
Exothermic Reactions • A reaction that releases energy during the reaction is known as an exothermic reaction. • Energy often given off in the form of heat • Energy listed as a product in the equation Reactants Products + Energy
Endothermic Reactions • A reaction that requires energy during the reaction is known as an endothermic reaction. • Energy often absorbed in the form of heat, so the substance feels cold • Energy listed as a reactant in the equation Energy + Reactants Products
Phase Changes are Exo- and Endothermic! Absorbs Energy
Phase Changes are Exo- and Endothermic! Release Energy
Class Example • Is the following reaction endothermic or exothermic? NH4NO3 + 453 kJ/mol HNO3 + NH3
Table Talk • Is the following reaction endo- or exothermic? 2H2 + O2 → 2H2O + 484 kJ/mol
Table Talk • I have a pot of water and I heat it up until it turns into gas. Is this an endothermic or exothermic process?
Stop and Jot • 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?
The Breakdown of Cheetos in Our Bodies • Before we can use food it needs to be converted to glucose. • Glucose is the only usable form that we humans can use to make ATP. C6H12O6 (aq) + 6O2 (g) → 6CO2 (g) + 6H2O (l) + 2880 kJ/mol
Work Time Complete the worksheet with your table.
Exit Slip • Elephant Toothpaste Chemistry: Ever wanted to make elephant toothpaste? • The overall equation for this reaction is: • 2 H2O2(aq) --> 2 H2O(l) + O2(g) + 4080 kJ/mol • However, the decomposition of the hydrogen peroxide into water and oxygen is catalzyed by the iodide ion. • H2O2(aq) + I-(aq) --> OI-(aq) + H2O(l) + 2000 kJ/mol • H2O2(aq) + OI-(aq) + 1500 kJ/mol--> I-(aq) + H2O(l) + O2(g) • WHICH OF THE THREE ARE ENDOTHERMIC AND WHICH ARE EXOTHERMIC? HOW DO YOU KNOW? (2 SENTENCES)
Closing Time • No Homework tonight!