Which statement best describes a chemical change?

It creates new substances with different properties.

It involves only physical changes.

It mixes different substances without changing them.

It only changes the shape of the substances.

What best illustrates the law of conservation of matter?

The total mass of reactants equals the total mass of products after a chemical reaction.

Matter can disappear during a reaction.

Matter can be created during a reaction.

Mass can change if temperature changes.

Which of the following describes a physical property?

The flammability of a substance.

Which of these is a sign that a chemical change has occurred?

The substance dissolves in water.

Which process demonstrates the law of conservation of matter?

Combining vinegar and baking soda produces carbon dioxide gas while the total mass remains unchanged.

Melting chocolate decreases its mass.

Burning paper creates ash that weighs less than the original paper.

Dissolving salt in water increases the weight of the solution.

What happens during a chemical change that does not occur during a physical change?

The substance can be reversed easily.

Chemical changes, physical changes, law of conservation of matter

SC.8.P.9.2 • Students will differentiate between physical and chemical changes. • Students know the characteristics of physical (change in state of matter) and chemical changes. (i.e.: new odor, change in color, new substance, change in temperature) • Students will identify a change as physical, or chemical given evidence. • Students will explain that mass is conserved when substances undergo physical and chemical changes, according to the law of conservation of mass. • Students will summarize the Law of Conservation of mass, explaining that mass cannot be created or destroyed, only transferred. • Students will describe how temperature influences chemical changes. • Students will know thermal energy increases the movement of atoms/molecules. • Students will explain that scientific explanations are based on empirical evidence, logical reasoning, predictions, and modeling.

Science Exam Parts of the Atom: The atom consists of a nucleus at its center, containing protons (positively charged) and neutrons (neutral), while electrons (negatively charged) orbit in electron shells around the nucleus. Atomic Number: The atomic number of an element is the number of protons in its nucleus. It defines the element and determines its place on the periodic table. Properties of Metals: Metals have properties like conductivity, malleability (can be flattened into sheets), and ductility (can be drawn into wires). Elements, Compounds, and Mixtures: Elements consist of only one type of atom. Compounds are made of two or more different elements chemically bonded. Mixtures are combinations of substances that are physically mixed but not chemically bonded. Homogeneous and Heterogeneous Mixtures: Homogeneous mixtures have a uniform composition (e.g., saltwater), while heterogeneous mixtures have different phases (e.g., oil and water). Changes of State: Changes like melting, evaporation, and condensation are examples of physical changes of state. Chemical and Physical Properties: Chemical properties describe how a substance can change to form a new substance, while physical properties are characteristics like color, texture, and state (solid, liquid, gas). Physical and Chemical Change: A physical change involves the appearance or state of matter, but the substance remains the same. A chemical change involves the formation of new substances. Chemical Equations: Chemical reactions can be represented with chemical equations that show reactants (what you start with) and products (what is formed). Chemical Formulas: Chemical formulas represent the composition of compounds. For example, NaHCO3 is sodium bicarbonate, consisting of one sodium (Na), one hydrogen (H), one carbon (C), and three oxygen (O) atoms. Energy: Types of Energy: Energy can be kinetic (related to motion), potential (stored energy), thermal (heat energy), electrical, chemical, and more. Units of Energy: Common units of energy include joules (J) and calories (cal). Law of Conservation of Energy: Energy cannot be created or destroyed, only transferred or transformed from one form to another. Energy Transfer and Transformation: Energy moves from one object to another, changing forms along the way. Useful and Waste Energy: Useful energy is what can be harnessed and used for a specific purpose. Waste energy is energy that is not used and is often lost. Energy Flow Diagrams: These diagrams show how energy is transferred or transformed within a system. Energy Efficiency: Efficiency is a measure of how much useful energy is obtained from a system. It can be calculated using the equation: Efficiency = (Useful Energy Output / Total Energy Input) x 100%. Fossil Fuels and Renewable Energy: Fossil fuels, like coal, oil, and natural gas, are non-renewable sources of energy. Renewable energy sources include solar, wind, and hydroelectric power. Variables: Independent Variable: The variable that is manipulated or changed in an experiment. Dependent Variable: The variable that is measured or observed and is affected by changes in the independent variable. Controlled Variables: Factors that are kept constant to ensure a fair and accurate experiment.

SC.8.P.9.1-Explore the Law of Conservation of Mass by demonstrating and concluding that mass is conserved when substances undergo physical and chemical changes.

PB-SC.8.P.9.1 (H) - Explore the Law of Conservation of Mass by demonstrating and concluding that mass is conserved when substances undergo physical and chemical changes.

SC.8.P.9.1 - Explore the Law of Conservation of Mass by demonstrating and concluding that mass is conserved when substances undergo physical and chemical changes.

PB-SC.8.P.9.2 (M) - Differentiate between physical changes and chemical changes.

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