Exothermic and Endothermic Reactions

What is an exothermic reaction?

What is an endothermic reaction?

What’s the main difference between an exothermic and endothermic reaction?

Is the reaction when Sara mixed water and calcium chloride exothermic or endothermic?

Is the reaction when Samuel mixed baking soda with hydrochloric acid exothermic or endothermic?

What kind of reaction occurs when lighting a candle?

What kind of reaction occurs when melting an ice cube?

What kind of reaction occurs when freezing water to make ice?

What kind of reaction occurs when water evaporates?

Are exothermic and endothermic reactions considered physical changes?

Exothermic and Endothermic Reactions

Exothermic Reaction: Releases energy, primarily as heat during a chemical reaction.
Endothermic Reaction: Absorbs energy during a chemical reaction, leading to a temperature drop.

Key Differences

Exothermic reactions release energy and typically feel warm to the touch.
Endothermic reactions absorb energy and generally feel cool to the touch.

Reaction Examples

Calcium Chloride and Water: Mixing causes a temperature increase from 23°C to 52°C, indicating an exothermic reaction.
Baking Soda and Hydrochloric Acid: Reaction results in bubbling and a temperature drop from 52°C to 22°C, demonstrating an endothermic reaction.

Common Exothermic Reactions

Candle Lighting: Heat released as the candle burns, exemplifying an exothermic process.
Freezing Water: Energy is released as water molecules solidify into ice, characterizing an exothermic reaction.

Common Endothermic Reactions

Melting Ice: Energy is absorbed to melt the ice, illustrating an endothermic process.
Water Evaporation: Heat absorbed transforms liquid water into vapor, showcasing an endothermic reaction.

Reaction Types

Both exothermic and endothermic reactions are classified as chemical changes, reflecting the transformation of substances during the process.

This quiz covers key concepts related to exothermic and endothermic reactions. Learn the definitions, compare the two types of reactions, and understand their energy changes. Perfect for chemistry students looking to solidify their knowledge in this area.