The Classification of Matter

Matter is described as “anything that takes up space and has mass.”

Organization of Matter Pure substances Mixtures

Only one kind of particle Division of Matter Mixtures Pure Substances Two or more pure substances physically placed together, not chemically joined Only one kind of particle

physical combinations of pure substances Mixtures physical combinations of pure substances

Mixtures Since a mixture is only a physical combination of different atoms, it is NOT a pure substance.

Mixtures Heterogeneous Homogeneous Different kinds of particles are visible. Different kinds of particles are not visible. Example: sand and rocks Example: salt water

another name for a homogeneous mixture solution another name for a homogeneous mixture

Solution vs. Pure Substance A pure substance has a fixed composition. A mixture has a variable composition.

Only one kind of particle Pure Substances Only one kind of particle Elements Compounds

Elements Substances that cannot be broken down into simpler substances by ordinary chemical means

The smallest “piece” of an element that is still the element Atom The smallest “piece” of an element that is still the element Made up of subatomic particles: protons, neutrons, and electrons

Question What is the smallest piece of an element that is still that element? Hydrogen Symbol Atom Mixture Pure substance Atom - Clipart.com Item #20307567

Naturally occur in 3 categories Elements Naturally occur in 3 categories Monatomic He Diatomic Polyatomic O2, H2 S8 Molecules

Berzelius’s System Chemical Symbol One or two letters represent the name of an element. The 1st letter is always uppercase. The 2nd letter is always lowercase.

Question What is true about the symbols that stand for an element? They use Greek letters. The 1st letter is never capitalized. The 2nd letter is never capitalized. Berzwali invented this system. Atom - Clipart.com Item #20307567

Molecules Two or more atoms that are chemically bonded together Can be atoms of the same element chemically bonded together Can be atoms of different elements chemically bonded together

Question Atoms are related to elements as molecules are related to ______. bonds particles mixtures compounds symbols Atom - Clipart.com Item #20307567

Compounds Molecules from two or more different elements that have been chemically bonded together

Only one kind of particle Pure Substances Only one kind of particle Elements Compounds

Compounds Can be expressed by a “formula” which tells the number of atoms of each element present

Compounds Can be expressed by a “formula” which tells the number of atoms of each element present Example: H2 O 2 hydrogen atoms 1 oxygen atom

Compounds Formula Tells the type and number of atoms that are present in one molecule of a compound Example: Fe2O3 Subscripts

Question Although an element can exist as atoms or molecules, a compound always exists as _________. atoms elements mixtures pure substances molecules Atom - Clipart.com Item #20307567

Subscript A number that indicates the amount of atoms or groups of atoms in a formula

There are 22 hydrogen atoms. Subscript C 12 H 22 O 11 There are 12 carbon atoms. There are 11 oxygen atoms. There are 22 hydrogen atoms.

Question What is the name for the number in a formula which indicates how many atoms of each element are present? Coefficient Subscript Compound Mixture Atom - Clipart.com Item #20307567

Coefficient A number in front of a formula which tells how many molecules or atoms are present

Coefficient Example: 5 Fe2O3 Coefficient Subscripts

Question What is the name for the number that indicates how many molecules of a compound are present? Mixture Substance Subscript Coefficient Atom - Clipart.com Item #20307567

Only one kind of particle Division of Matter Mixtures Pure Substances Two or more pure substances physically placed together, not chemically joined Only one kind of particle

Question If a substance is not a pure substance, it is a _____. mixture element compound molecule atom Atom - Clipart.com Item #20307567

Mixtures Heterogeneous Homogeneous Different kinds of particles are visible. Different kinds of particles are not visible. Example: sand and rocks Example: salt water

Only one kind of particle Pure Substances Only one kind of particle Elements Compounds Cannot be broken into simpler substances by ordinary chemical means Molecules from two or more different elements that have been chemically bonded together

Classification of Matter Elements H2 molecules O2 molecules Spartan Software, p. 30 of Chem. textbook

Classification of Matter Compounds H2O molecules H2O2 molecules Spartan Software, p. 30 of Chem. textbook

Classification of Matter Mixtures H2 and O2 molecules H2O and H2O2 molecules Spartan Software, p. 30 of Chem. textbook