Lab 8 Lab 8 “Endo and Exo The Reaction Twins”

The student will investigate and understand chemical changes in matter

The student will be able to recognize that some types of chemical reactions require continuous input of energy (Endothermic) and others release energy (Exothermic)

Endothermic ReactionExothermic Reaction

A chemical reaction that requires continuous input of energy.

It feels cold.Endothermic reaction of barium hydroxide and an ammonium salt. Mix the two solids; they react, and the products dissolve in water of hydration. The reaction flask may be passed around for students to feel how cold it is.

A chemical reaction that continuously releases energy.

It feels hot.Light Energy could be released in the exothermic reaction taking place in things such as glow sticks.

Temperature change is an indicator or clue of a chemical reactionThe temperature change happens because of the combination of chemicals and energy

There are two types of chemical reactions that cause a temperature changeEndothermic ReactionsExothermic Reactions

Endothermic and Exothermic Reactions are shown using a line graph

The graph is written as change in temperature over time

In Endothermic Reactions, there is a decrease in temperature or a temperature drop.

Endothermic Reactions require more energy to break the original chemical bonds and form new ones

Energy is absorbed from the environment through a continuous input of energy and the product feels coldCold Packs

Endothermic in Blue

Exothermic Reactions give off energy in the form of thermal energy (heat). (increase in temperature)

Exothermic Reactions require Less energy is to break bonds to form new onesBurning wood, paper, hand warmers

We use a line graph to show the changes in endothermic and exothermic reactions

Exothermic reaction in Green

The steeper the line(Slope) the faster the energy change