Chemical Reactions

A chemical reaction is a process that leads to the transformation of one set of chemical substances to another. It involves the breaking and forming of chemical bonds to create new substances with different properties.

Key Concepts

Reactants: The substances that undergo a chemical change.
Products: The new substances formed as a result of the chemical reaction.
Chemical Equations: Represent the reactants and products in a chemical reaction.
Endothermic Reaction: Absorbs heat from the surroundings.
Exothermic Reaction: Releases heat into the surroundings.

Types of Chemical Reactions

There are several types of chemical reactions:

Synthesis Reaction: Two or more substances combine to form a more complex product.
Decomposition Reaction: A compound breaks down into simpler substances.
Single Replacement Reaction: An element replaces another element in a compound.
Double Replacement Reaction: The positive and negative ions of two ionic compounds exchange places.
Combustion Reaction: A substance reacts with oxygen, releasing energy in the form of heat and light.

Factors Affecting Chemical Reactions

Several factors can influence the rate of a chemical reaction:

Temperature: Increasing temperature generally leads to a faster reaction rate.
Concentration: Higher concentration of reactants can lead to a faster reaction rate.
Catalysts: Substances that increase the rate of a chemical reaction without being consumed in the process.
Surface Area: In the case of solid reactants, increasing the surface area can lead to a faster reaction rate.

Study Guide

When studying chemical reactions, it's important to understand the following:

Identify the reactants and products in a chemical equation.
Understand the different types of chemical reactions and their characteristics.
Be able to balance chemical equations to satisfy the law of conservation of mass.
Recognize the factors that can affect the rate of a chemical reaction.
Be familiar with common examples of chemical reactions in everyday life.

◂Science Worksheets and Study Guides Eighth Grade. Chemical reactions

Vocabulary/Answer key

Chemical reactions

Vocabulary/Answer key

Chemical reactions

The resources above cover the following skills:

Chemistry: Students will use scientific skills and processes to explain the composition, structure, and interactions of matter in order to support the predictability of structure and energy transformations.

Conservation of Matter: Provide evidence to support the fact that the idea of atoms explains conservation of matter.

Cite evidence from investigations that the total mass of a system remains the same throughout a chemical reaction because the number of atoms of each element remains the same.

Give reasons to justify the statement, 'If the number of atoms stays the same no matter how the same atoms are rearranged, then their total mass stays the same.'

Physical and Chemical Changes: Provide evidence to support the fact that common substances have the ability to change into new substances.

Investigate and describe the occurrence of chemical reactions using the following evidence: Color change; Formation of a precipitate or gas; Release of heat or light.

Use evidence from observations to identify and describe factors that influence reaction rates: Change in temperature; Acidity.

Identify the reactants and products involved in a chemical reaction given a symbolic equation, a word equation, or a description of the reaction.

Provide data from investigations to support the fact that energy is transformed during chemical reactions.