Endothermic / Exothermic Lab

Part 1 – Baking Soda and Vinegar

Vinegar Vinegar + Baking Soda

General Observations

Exact Temperature

Vinegar Vinegar + Baking Soda

General Observations

Clear Liquid; Slightly cool

Bubbles occur; substance

changes color; Solution feels

colder

Exact Temperature 21oC 14oC

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

W WaterCalcium

Chloride and Water

General Observations

Exact Temperature

Part 2 – Calcium Chloride and Water

W Water Calcium Chloride and Water

General Observations

Clear; Room Temperature

Solution gets warmer immediately; No bubbles occur;

Changes color slightly

Exact Temperature 21oC 32oC

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?– Answers can vary – Opinion question

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” ArticleReactants 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 + Waterchloride

Calcium + HydrochloricOxide 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