Matter and Change

extensive properties:•depends on the amount of matter in a sample volume and mass

intensive properties•depends on the type of matter, NOT the amount hardness, boiling/melting point, density…

Matter

Elements•all particles are alike•serve as the building materials of all matter•smallest particle of an element that is still recognizable is called an atom•can’t be broken down anymore by “normal means”•found on the periodic table• currently there are about 118 elements• chemical symbols are used to

represent the elements• Example: C=carbon, N=nitrogen…..

Compounds and Molecules (over 10 million exist)

•two or more elements chemically combined

•a pure substance that is composed of two or more elements in a fixed ratio

•the properties of a compound are different than the elements that make it up

•can be broken down into the elements that make them up

•chemical formula

• a combination of symbols and subscripts that indicates the number and types of elements in a compound

• example: sugar is C6H12O6

• looks nothing like C, H, O by themselves

• can be broken down when burned

Chemical formula: A combination of symbols and subscripts that indicates the number and types of elements in a compound.

Symbol for sulfur Symbol for oxygen

Subscript for oxygenSymbol for copper

Phase: The physical form a substance is in, such as solid (s), liquid (l), or gas (g). Phase is greatly influenced by temperature.

Aqueous: A substance is aqueous (aq) when it is dissolved in water.

Matter

MixturePure Substance

YES NO

YES NO

Homogeneous Mixture

Heterogeneous Mixture

NO

Element(118)

Compound or Molecule

(millions)

YES NO

Solution Colloid

Are the particles one kind of atom?

Are all the particles alike?

Are the particles well-mixed and mixed evenly?

Is one substance dissolved in another?

YES

Pure elements

Elements made of SINGLE ATOMS

An element made of MOLECULES

Mixture of TWO elements

Mixture of THREE elements

Pure compounds

Mixture of TWO compounds

Elements and Compounds “Quiz”

Element, Compound, or Mixture “Quiz”

Physical properties• characteristics that can be easily observed without changing the substance that help identify it

• example: mass, volume, color, melting point, boiling point, shape, texture, hardness…

Physical change• simply change a physical property without changing what it is

• can be reversible or irreversible• example: ripping and folding paper, melting, sanding something, breaking it in half…

Physical vs. Chemical

Chemical properties• describe a substance’s ability to change into a different substance

• hard to observe and only becomes visible during a chemical reaction.

• examples: flammability, chemically reactive

Chemical change (chemical reaction)• the actual process of changing a substance into something new•often transfer of energy (heat), color change, production of gas or formation of a precipitate (solid that forms and settles out of a liquid)

• example: burning, rusting, mixing chemicals that react…

Physical or Chemical Change “Quiz”

conservation of mass• during any chemical reaction, the mass of the products is always equal to the mass of the reactants

• matter cannot be created nor destroyed