introduction to chemistry what matters? chapters 2 & 3

Introduction to Chemistry

What Matters?

Chapters 2 & 3

SI Units

• Length – meter

• Mass – kilogram

• Time – second

• Temperature – Kelvin

• Quantity of Matter – mole

• Volume - liter

Commonly Used Prefixes

• Centi- 1/100 or 0.01

• Kilo- 1000 or 1.0 x 103

• Milli- 1/1000 or 0.001

Matter

• Def- anything that has mass and occupies space

• 3 States of matter– Solid– Liquid– Gas

Phase Changes

• Melting

• Freezing

• Vaporization/Evaporation

• Condensing

• Sublimation

• Deposition

Changes of State

Melting/Freezing

• Energy must be ADDED for a substance to melt

• Energy must be REMOVED for a substance to freeze

Vaporization & Condensation• Energy must be ADDED for a

substance to boil

• Energy must be REMOVED for a substance to condense

Deposition/Sublimation

• Energy must be added for a substance to sublime

• Energy must be removed for a substance to undergo deposition

Law of Conservation of Energy

• Energy cannot be created or destroyed

• Energy of a reaction MUST be conserved

Elements, Compounds& Mixtures

Elements

• An element is matter in its simplest form

• Cannot be broken down by chemical means

• Periodic Table (114 elements)

Compounds

• Are combinations of elements

• Have the same composition

• Can be broken down by chemical means

Mixtures

• Have variable composition

• Can be separated physically or chemically

• Homogeneous Mixtures – are the same throughout

• Heterogeneous Mixtures – have different regions

Law of Conservation of Matter

• Matter cannot be created or destroyed

• Mass of a chemical reaction MUST be conserved

Separatory Techniques

Filtration

• Used for separating undissolved solids

• Pour through a mesh (filter paper)

Distillation

• Used to separate dissolved solids or liquid mixtures

• Uses physical changes

Chromatography

• Uses chemicals to separate the pigments of plant or chemicals

• Various Methods– Gas chromatography– Liquid chromatography– Thin-layer chromatography– Ion-exchange chromatography

Chemical vs Physical

Physical Properties

• A set of characteristics unique to a substance

• Odor• Color• Volume• State• Density• Boiling point• Melting point

Chemical Properties

• The ability of a substance to form new substances

• Wood burning • Iron rusting• Digestion• photosynthesis

Physical Change

• Does NOT change the identity of the substance

• Composition remains the same

Chemical Change

• Changes the composition of the substance

• Has new physical properties that differ from the original