Unit 2: Matter
In Unit 2, students will study matter, its properties, how it changes, and how substances can be combined. Students will also be introduced to foundational chemistry concepts such as atoms, elements, molecules, compounds, mixtures, solutions, and the work of chemists.
Matter is anything that has mass and takes up space.
Matter can be identified and compared using its physical properties.
Matter is made of particles too small to see.
Matter can exist as a solid, liquid, or gas.
Adding or removing thermal energy can cause matter to change states.
A mixture contains two or more substances that are physically combined.
Substances in many mixtures keep their original physical properties.
A solution is a special type of mixture in which one substance dissolves in another.
Matter is conserved when substances form a solution—it does not disappear.
A physical change changes the form or appearance of matter without forming a new substance.
A chemical change forms one or more new substances.
Scientists use observations, models, investigations, and evidence to understand matter.
Scientific discoveries about matter have changed over time as scientists gained new evidence and technology.
Matter
Anything that has mass and takes up space.
Physical Property
A characteristic of matter that can be observed, measured, or tested without changing the substance into something new.
Mass
The amount of matter in an object.
Volume
The amount of space an object or substance takes up.
Magnetism
The ability of a material to attract or be attracted to a magnet.
Relative Density
A comparison that helps determine whether an object will sink or float in a substance such as water.
Solubility
The ability of a substance to dissolve in another substance.
Conductor
A material that allows thermal or electrical energy to move through it easily.
Insulator
A material that slows or prevents the movement of thermal or electrical energy.
Particle
A very small piece of matter. Matter is made of particles that may be too small to see.
Atom
A very small particle that makes up matter.
Nucleus
The center of an atom.
Proton
A positively charged particle found in the nucleus of an atom.
Neutron
A particle with no electrical charge found in the nucleus of an atom.
Electron
A negatively charged particle found outside the nucleus of an atom.
Element
A pure substance made of only one type of atom.
Molecule
Two or more atoms joined together.
Compound
A substance formed when atoms of two or more different elements are chemically combined.
Solid
A state of matter with a definite shape and definite volume.
Liquid
A state of matter with a definite volume that takes the shape of its container.
Gas
A state of matter that does not have a definite shape or definite volume.
Change of State
A physical change in which matter changes from one state to another because thermal energy is added or removed.
Mixture
Two or more substances physically combined while the substances keep many of their original properties.
Solution
A mixture in which one substance is evenly dissolved in another substance.
Solute
The substance that is dissolved in a solution.
Solvent
The substance that dissolves the solute.
Concentration
The amount of solute dissolved in a certain amount of solution.
Alloy
A mixture containing two or more elements in which at least one is a metal.
Conservation of Matter
The principle that matter is not lost when substances are combined or changed. The matter is still present even if it looks different.
Physical Change
A change in the size, shape, form, or state of matter that does not create a new substance.
Chemical Change
A change in which one or more new substances are formed.
Chemistry
The study of matter, its properties, and how substances interact and change.
Chemist
A scientist who studies matter and how substances interact and change.