Chapter 2

Matter & Change

Matter

Anything that has mass & takes up spaceAll materials you hold or touch

Air you breathe

Mass = a measure of the amount of matter an object contains

Volume = measure of the space occupied by an object

Substance = type of matter with a fixed composition (can be an element or a compound)

Physical Properties

Quality or condition of a substance that can be observed or measured without changing the substances composition

color, shape, odor, texture, density

Intensive Properties

Physical properties depend upon the type of matter in a sample, not the amount, it helps you determine what a substance is Melting point, Density, Viscosity, Color

Every sample of a given substance has the identical intensive properties because every sample has the same composition

Extensive Properties

Physical properties that depend upon the amount of matter in a sample on hand & do not help you determine what a substance is Mass Length Volume

This blue crystal has a mass of 0.32g and a density of 3.20 g/cm3.It is not malleable and has a volume of 0.1 cm3

Which properties listed are intensive?3.2 g/cm3, not malleable, blue

Which properties listed are extensive?0.32g, 0.1cm3

States of Matter: Solid

Particles are in a fixed position – therefore, they have a rigid structure

Particles have almost no freedom to change position; they change position around a fixed point

Not easily compressed

States of Matter: Liquid

Particles are close together and move freely around each other

Liquids vary in viscosity (the resistance of a fluid to flow – thickness)

molasses vs. vinegar Not easily compressed

States of Matter: Gas

Particles expand to fill available space, move constantly and rarely stick together

Gas exerts pressure (force exerted per unit area of a surface) and will escape its container if possible – balloons, propane tanks, gas grills

Easily compressed

Physical Changes

Properties of a material change; however, the composition of the material does not change

Can be reversible Melting, boiling

Can be Irreversible Slicing, cutting

Mixtures

Mixture a combination of two or more components

Hetero vs. Homogeneous

Homogeneous mixture = contains two or more gases, liquids, or solids that are blended evenly throughoutVinegar, salt water, margarine,

gasoline Heterogeneous mixture = a mixture in which different materials can be distinguished easilyFruit salad, trail mix, granite

Which is which?

Heterogeneous Homogeneous

P

Separating Mixtures

Filtration = separates a solid from the liquid in a heterogeneous mixture

Distillation = process used to separate dissolved solids from a liquid (boiling and then condensing)

Evaporation

Substance

Matter that has a uniform and definite composition

Every sample has identical intensive properties because every sample has the same composition

Elements and Compounds

Compound two or more elements that are chemically combined, can be broken down into simpler substances

Water Hydrogen & Oxygen Element substance that cannot be broken down into simpler substances composed of one type of atom

Chemical Properties of Matter

The way a substance reacts with another to form a new substance with different properties

Involve reactivity – ability of a substance to combine chemically with another substance

Chemical properties of compounds vary from the individual elements that they are made from

Chemical Changes

Chemical changes are changes in composition – atoms are changed or rearranged

bumper with rust

Law of Conservation of Mass

Mass can not be created or destroyed

Total mass of all matter stays the same as before the change – it changes from one form to another

From ice to liquid to gas, it will all have the same mass

Molecules

Molecule smallest unit of a substance that exhibits all of the properties characteristic of that substance

Chemical Formula

Chemical shorthand that uses symbols and numbers indicating the elements in a compound and their ratios

C6H8N4O2 Theobromine (chocolate)

C6H12O6 Fructose (sugar)

The End