Chapter 2 Energy and Matter

Energy Kinetic – Potential –

Measuring Energy Calorie = food calorie –1 Cal = 1 cal –Amount of heat needed to raise 1 g of water 1 o C Joule –SI unit –

Law of Conservation of Energy

Practice Convert J to cal Convert cal to Joules Convert Cal to Joules

Temperature Scale of ’ Amount of heat (energy, molecular movement) in something Scales –

Heat Flow In what direction does heat flow? –From hot things to cold things –From cold things to hot things

Conversions o C to o F o C to K

Matter Defined: –

States of Matter Solid – Liquid –

States of matter Gas – Plasma –

Properties Physical Properties – Chemical Properties –

Changes in Matter Physical Changes –Changes in

Changes in Matter Chemical Changes –Changes in

Law of Conservation of Mass Mass can be The total mass

Pure Substances Element –A–A substance that cannot be separated into simpler substances

Elements ~111 presently known elements Building blocks of all substances At room temperature: – – – Figure 3.3 – distribution of elements in galaxies, earth’s crust, seawater and air, and human bodies

Elements Names of the elements –Greek –Latin –German –Properties of elements –Scientist who discovered it –Location where discovered

Elements Arranged in the Periodic Table (inside front cover) Symbols –One or two letters Usually part of name Some symbols are Latin/Greek name

Elements Classification –Metal –Nonmetal –Metalloid See Table 3.5 (page 54)

Elements Metals: –U–Usually –G–Good –H–High –H–High –U–Usually don’t combine with each other –R–Readily combine with nonmetals

Nonmetals: –Solids (C, P, S, Se, I); Liquid (Br); Gases (all others) – – –Will combine with each other –Will combine with metals or metalloids –Some found uncombined in nature (noble gases)

Elements Metalloids –Have properties of – –Some used for semiconductors in electronics

Pure Substances II Compound –Two or more elements –

Compounds Two or more elements chemically combined New properties Can be

Compounds Molecular –Held together with –Molecule: –Water is an example

Compounds Ionic –Ion: Cation – Anion – –Held together by ionic bond –

Compounds Diatomic Molecules –Always only –7 naturally occurring

Substances and Mixtures Pure Substance: a particular kind of matter with a – – Mixture: –Not chemically combined

Matter Pure substances (homogeneous composition) Mixtures of two or more substances ElementsCompounds Solutions (homogeneous composition – one phase) Heterogeneous mixtures (two or more phases) Figure 3.2 (page 48)

Types of Mixtures Heterogeneous mixtures – –

Types of Mixtures Homogeneous mixtures – – –

Separating Mixtures Do NOT cause chemical changes Heterogeneous Mixtures –

Separating Mixtures Homogeneous Mixtures –

Separating Mixtures Homogeneous Mixtures –

Separating Mixtures Homogeneous Mixtures –