Introduction To Chemistry A Motivational Lesson

CHEMISTRY ELEMENT, COMPOUND AND MIXTURE

ELEMENT Non-Metal Metal (l) (l) (s) (g) (s) (g) – gas (l) – liquid (s) - solid

Examples of Metals ( Sodium ) Na Use : Sodium Lamp

The periodic table Increasing metallic character Be B C N O F Ne Na Mg Al Si P S Cl Ar Increasing metallic character K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn Fr Ra Ac Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr Metals Metalloids Nonmetals This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License

What is an element ? Element A chemical substance Simplest substance Cannot be decomposed to a simpler substance Built up from one type of atoms only

Use : Electric Conductor Copper Cu Use : Electric Conductor

What is a Compound ? A Chemical Consists of 2 or more elements chemically combined Chemical Bond between the particles

Sodium Chloride Use : Flavor for Food Constituents : Na , Cl

Glucose Use : Carbohydrates Constituents : H , C , O

What is a Mixture ? Substance consisting of 2 or more substances physically combined together Components : Elements or/and compounds Components can be separated by physical means

Mixtures Homogeneous Mixture – composition and properties are uniform (sometimes called a solution) Air – principal components include O2, N2 & CO2 Vodka – principal components are EtOH & H2O Brass – solid solution of Cu and Zn Ruby – solid solution of Al2O3 and Cr2O3 This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License

Mixtures Heterogeneous Mixture – composition and properties are non-uniform Chocolate Chip Cookie – chocolate, sugar, dough, etc. Concrete – cement, sand, aggregate Vomit – Depends upon previous intake of food and drink This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License

Air– Oxygen, Nitrogen, Carbon dioxide, water vapor etc Examples of Mixtures Air– Oxygen, Nitrogen, Carbon dioxide, water vapor etc

Components : Lactose, water, proteins, vitamins, minerals etc Milk Components : Lactose, water, proteins, vitamins, minerals etc

Properties of Matter Types of matter are distinguished by their properties There are two categories of properties that concern us: Physical properties Chemical properties If two samples of matter have the same properties, they must be the same substance This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License

Changes in Matter Gas Sublimation Evaporation Deposition Condensation Chemical Physical Gas Sublimation Evaporation Deposition Condensation Changes don’t have to be on a macro scale - at the very trace analysis scale can also get changes at ppb (109) and ppt (1012) level Melting Solid Liquid Freezing This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License

Properties of Matter Physical properties –the identifying characteristics of matter Some properties can be readily measured with our senses odour Colour Instruments are needed to measure other properties electrical resistivity compressibility hardness melting point radioactivity This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License

Changes in Matter Physical change Substance changes physical appearance without altering its identity e.g. changes of state ice melting to form water This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License

Physical properties METALS NON METALS good conductors of electricity Ductile malleable, lustrous typically: solid high melting point good conductors of heat NON METALS poor conductors of electricity not ductile not malleable solid, liquid or gas low melting point poor conductors of heat You have already been through the basic trends in the periodic table in your 2nd lecture. These are some general physical and chemical properties, we will look at some of these in some more detail. These are really the 2 categories that concern us: Physical and chemical properties. This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License

Changes in Matter Chemical changes (or chemical reactions) Substances transform into chemically different substances i.e. identity changes e.g. decomposition of water This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License