Hot and Cold: Endothermic and Exothermic Reactions

Add to list Go to activity
Visitors mix urea with water in one flask and mix calcium chloride with water in another flask. They observe that the urea flask gets cold and the calcium chloride flask gets hot. Visitors learn that some chemical reactions release energy in the form of heat and others absorb energy, becoming cold. They learn that there are practical uses for these kinds of chemical reactions.

Quick Guide

Preparation Time:
30 to 45 minutes
Learning Time:
Under 5 minutes
Estimated Materials Cost:
$1 - $5 per group of students
Age Range:
Ages 6 - adult
Resource Types:
Activity, Experiment/Lab Activity
Language:
English

Materials List (per group of students)

  • Two 250-ml Erlenmeyer flasks
  • Two 1-tsp (4-ml) measuring spoons (one yellow; one red)
  • Two small plastic funnels
  • One 25-ml graduated cylinder
  • CaCl2 (calcium chloride) pellets (keep 1000 g on hand)
  • NH2CONH2 (urea) (keep 1000 g on hand)
  • One 250-ml squirt bottle
  • Super glue
  • Two small jars (about 8-oz size) with lids
  • Two large jars (32-oz or larger) with lids

Keywords

Subjects

  • Engineering and Technology
    • Engineering
      • Chemical Engineering
    • Technology
  • Physical Sciences
    • Heat and Thermodynamics
      • Heat and Temperature
      • Thermodynamics and Entropy
    • Energy
    • Chemistry
      • Chemical Bonding
      • Chemical Reactions
    • States of Matter
    • Structure and Properties of Matter
  • Life Sciences
    • Human Body
  • The Nature of Science
    • Science and Society
  • The Nature of Technology
    • Technology and Society
      • Technology and the Environment

Audience

To use this activity, learners need to:

  • see
  • read

Learning styles supported:

  • Involves hands-on or lab activities

Other

Components that are part of this resource:

This resource is part of:

Access Rights:

  • Free access

By:

Rights:

Funding Source:

  • National Science Foundation