Classification of Matter Chapter 15

Composition of Matter – Sec. 1  Pure Substances – Same composition throughout – Either an element or compound  Element – All one type of atom – Everything made of atoms  Compound – Atoms of two or more elements

chemically bonded

together

Composition of Matter  Mixtures – Made of two or more substances that can be easily separated by

physical

means  Heterogeneous Mixture – Different materials can be seen easily – Granite, concrete, vegetable soup  Homogeneous Mixture (Solution) – Blended evenly throughout – Vinegar, Kool-aid

MATTER yes Mixtures Can it be separated?

no Substance Homogeneous Mixture Air, sugar water, stainless stell Heterogeneous Mixture Granite, wood, blood Compounds Water, sodium chloride Elements Gold, aluminum

Mixtures  Colloid ~ heterogeneous – Particles larger than solution but not heavy enough to settle out – Milk, paint, fog and smoke  Detecting Colloids – – Pass a beam of light through it  Colloid – See beam  Solution – Cannot see beam Particles big enough to scatter light –

Tyndall Effect

Mixtures  Suspension ~ heterogeneous – Not solution, not colloid – Muddy pond water – Heterogeneous mixture with a liquid and visible particles that settle

Properties of Matter Section 2

Physical Properties  Def: characteristic observed without changing the identity of the material – Ex: color, shape, size, density  Appearance  Behavior – Magnetic, malleable, flow of liquid

Separating Mixtures  Sand and Rock mixture?

– Filter or sift  Iron filings and Aluminum mixture?

– Magnet

Physical Change  Change in size, shape or state of matter and identity is same – Solid to a liquid?

– Yes

Freeze Melt Condense Evaporate Solid Liquid Gas

Physical Change  How to get pure water from salt water?

– Distillation – evaporate liquid and then recondense it

Chemical Properties and Changes 

Chemical Property

– can be observed only by changing the substance  – Flammability, reactivity, decomposition

Chemical Change

– change where a NEW substance is formed  Weathering – Physical or Chemical Change?

– Both!

Law of Conservation of Mass  Matter is neither created nor destroyed during a chemical reaction  Mass of all substances before = mass of all substances after change