PS.5 Physical and Chemical Changes

PS.5 Reactions Physical Science Middle Home

SOL PS.5 physical and chemical changes
PS.5 The student will investigate and understand changes in matter and the relationship of these changes to the Law of Conservation of Matter and Energy. Key concepts include physical changes chemical changes nuclear reactions Physical and Chemical Changes Matter can undergo physical and chemical changes. In physical changes, the chemical composition of the substances does not change. In chemical changes, different substances are formed. Chemical changes are often affected by the surface area/volume ratio of the materials involved in the change. The Law of Conservation of Matter (Mass) states that regardless of how substances within a closed system are changed, the total mass remains the same. The Law of Conservation of Energy states that energy cannot be created or destroyed but only changed from one form to another. Chemical Equations A chemical equation represents the changes that take place in a chemical reaction. The chemical formulas of the reactants are written on the left, an arrow indicates a change to new substances, and the chemical formulas of the products are written on the right. Chemical reactions are classified into two broad types: ones in which energy is released (exothermic) and ones in which energy is absorbed (endothermic). (The study of synthesis, decomposition, and replacement reactions can be reserved for high school chemistry.) Nuclear Reactions Another type of change occurs in nuclear reactions. Nuclear energy is the energy stored in the nucleus of an atom. This energy can be released by joining nuclei together (fusion) or by splitting nuclei (fission), resulting in the conversion of minute amounts of matter into energy. In nuclear reactions, a small amount of matter produces a large amount of energy. However, there are potential negative effects of using nuclear energy, including radioactive nuclear waste storage and disposal. STUDENTS SHOULD BE ABLE TO: PHYSICAL AND CHEMICAL CHANGES compare and contrast physical, chemical, and nuclear changes. analyze experimental data to determine whether it supports the Law of Conservation of Mass. CHEMICAL EQUATIONS identify the reactants and products in a given chemical equation formula. given chemical formulas, write and balance simple chemical equations. recognize that some types of chemical reactions require continuous input of energy (endothermic) and others release energy (exothermic). NUCLEAR REACTIONS describe, in simple terms, the processes that release nuclear energy (i.e., nuclear fission and nuclear fusion). c ompare and contrast these two types of nuclear energy. evaluate the positive and negative effects of using nuclear energy.

SOL PS.5 physical and chemical changes

physical changes
chemical changes
nuclear reactions

Physical and Chemical Changes

Matter can undergo physical and chemical changes.
- In physical changes, the chemical composition of the substances does not change.
- In chemical changes, different substances are formed.
- Chemical changes are often affected by the surface area/volume ratio of the materials involved in the change.
The Law of Conservation of Matter (Mass) states that regardless of how substances within a closed system are changed, the total mass remains the same.
The Law of Conservation of Energy states that energy cannot be created or destroyed but only changed from one form to another.

Chemical Equations

A chemical equation represents the changes that take place in a chemical reaction.
- The chemical formulas of the reactants are written on the left, an arrow indicates a change to new substances, and the chemical formulas of the products are written on the right.
- Chemical reactions are classified into two broad types: ones in which energy is released (exothermic) and ones in which energy is absorbed (endothermic).
- (The study of synthesis, decomposition, and replacement reactions can be reserved for high school chemistry.)

Nuclear Reactions

Another type of change occurs in nuclear reactions.
- Nuclear energy is the energy stored in the nucleus of an atom.
- This energy can be released by joining nuclei together (fusion) or by splitting nuclei (fission), resulting in the conversion of minute amounts of matter into energy.
- In nuclear reactions, a small amount of matter produces a large amount of energy.
- However, there are potential negative effects of using nuclear energy, including radioactive nuclear waste storage and disposal.

STUDENTS SHOULD BE ABLE TO:

PHYSICAL AND CHEMICAL CHANGES

compare and contrast physical, chemical, and nuclear changes.
analyze experimental data to determine whether it supports the Law of Conservation of Mass.

CHEMICAL EQUATIONS

identify the reactants and products in a given chemical equation formula.
given chemical formulas, write and balance simple chemical equations.
recognize that some types of chemical reactions require continuous input of energy (endothermic) and others release energy (exothermic).

NUCLEAR REACTIONS

describe, in simple terms, the processes that release nuclear energy (i.e., nuclear fission and nuclear fusion).
c ompare and contrast these two types of nuclear energy.
evaluate the positive and negative effects of using nuclear energy.