Matter and Energy Concepts

Reactants

• Elements or compounds on the left side of a chemical equation.

• Elements or compounds on the right side of a chemical equation.

• Substances that are produced in a chemical reaction.

• The process of breaking down compounds into simpler substances.

Subscript

• The number written before an element’s symbol in a chemical formula that indicates the number of atoms of a specific element.

• The number written after an element’s symbol in a chemical formula that indicates the number of atoms of a specific element.

• A symbol used to represent a chemical reaction in a formula.

• The total number of atoms in a chemical compound.

Mass

• The amount of matter in an object.

• The weight of an object in a vacuum.

• The volume of an object measured in liters.

• The density of an object calculated by mass divided by volume.

Brittleness

• The ability to bend without breaking.

• The ability to absorb energy without deforming.

• The ability to break or shatter under stress.

• The ability to stretch and return to original shape.

Mixture

• Two or more substances that are together, but not chemically combined.

• A single substance with uniform composition.

• A combination of elements that form a compound.

• A solution where one substance is dissolved in another.

Food Web

• A diagram that shows many overlapping food chains.

• A single linear path of energy flow in an ecosystem.

• A representation of the water cycle in nature.

• A chart showing the different types of soil in an area.

Ductility

• The ability to be stretched into a wire.

• The ability to be hammered into thin sheets.

• The ability to conduct electricity.

• The ability to resist deformation under stress.

Evidence of a Chemical Reaction

• Unexpected temperature change

• Formation of a solid

• Change in texture

• Change in size

Irregular Shaped Object

• An object that has a measurable length, width, or height.

• An object that does not have a measurable length, width, or height (e.g., marble, rock, key).

• An object that is perfectly spherical in shape.

• An object that can be easily categorized into geometric shapes.

Law of Conservation of Mass

• Matter can be created in a chemical reaction.

• Matter can be destroyed in a chemical reaction.

• Matter cannot be created or destroyed in a chemical reaction.

• The total mass of reactants is always less than the total mass of products.