Chemical Equations and Endo/Exo Reactions Study Guide

These flashcards cover key concepts related to chemical equations, endothermic and exothermic reactions, and the laws governing these chemical processes.

What do we call the substances that are present before a chemical reaction takes place?

Reactants

In a chemical equation, what do we call the substances produced as a result of a reaction?

Products

What does the Law of Conservation of Mass state?

Matter cannot be created or destroyed, only changed in forms.

If 500 grams of KCIO3 decomposes to produce 303 grams of KCI, how many grams of O2 are produced?

197 grams of O2.

When balancing the equation 4Fe + 3O2 → 2Fe2O3, how much oxygen is needed to react with 350 grams of iron?

150 grams of O2.

What is an endothermic reaction?

A reaction in which energy is absorbed, causing a decrease in temperature.

Give an example of an endothermic reaction.

Photosynthesis or a cold pack.

What is an exothermic reaction?

A reaction in which energy is released, generally causing an increase in temperature.

Give an example of an exothermic reaction.

A campfire, glow sticks, or fireworks.

Which reaction is endothermic if one shows a temperature decrease?

Reaction 2 is endothermic.

Which reaction is exothermic if one shows a temperature increase?

Reaction 1 is exothermic.

What will happen to the temperatures of both reactions over 24 hours?

Both reaction temperatures will eventually return to thermal equilibrium.

Calculate the temperature change in Reaction 2 if T1 = 3°C and Ti = 22°C.

ΔT = -19°C.