Endothermic / Exothermic Lab

Part 1 – Baking Soda and Vinegar Vinegar + Baking Soda General Observations Clear Liquid; Slightly cool Bubbles occur; substance changes color; Solution feels colder Exact Temperature 21oC 14oC Vinegar Vinegar + Baking Soda General Observations Exact Temperature

Part 1 – Analysis Questions How do you know a reaction occurred? Bubbles occurred Substance changed color / consistency Temperature decreased How did the temperature of the vinegar change when combined with baking soda? It decreased slightly Why do you think this happened? Answers can vary – Opinion question

Part 2 – Calcium Chloride and Water General Observations Clear; Room Temperature Solution gets warmer immediately; No bubbles occur; Changes color slightly Exact Temperature 21oC 32oC W Water Calcium Chloride and Water General Observations Exact Temperature

Part 2 – Analysis Questions How do you know a reaction occurred? Temperature increased How did the temperature of the water change when combined with calcium chloride? It increased significantly Why do you think this happened? Answers can vary – Opinion question

Part 1 & 2 Analysis Questions What do you think endothermic means? Answers can vary – Opinion question What do you think exothermic means?

Part 1 & 2 Analysis Questions List experimental errors

“What was Happening” Article What does exothermic mean? Gives off heat Exo - means out Thermal energy goes out What does endothermic mean? Uses heat Endo – Means in Thermal energy goes in

“What was Happening” Article Reactants Products Baking Soda + Vinegar _______ + ________ + ________ NaHCO3 + CH3COOH Water + Carbon + Sodium Dioxide acetate H2O + CO2 +C2H3NaO2

“What was Happening” Article Reactants Products _______ + ________ __________ + ___________ CaCl2 + H2O CaO + 2 HCl Calcium + Water chloride Calcium + Hydrochloric Oxide Acid

“What was Happening” Article What is a common use for calcium chloride? Driveway Salt Explain why calcium chloride would be helpful in the winter. Make sure you mention temperature changes and how this might help Calcium chloride when it comes into contact with water releases heat which melts the ice around it