Review: Classification of Matter Lesson 1 August 24 th, 2010

Grade 10’s Please Grab a text book from the side and flip to page 170. Start to fill in some of the blanks or just read through to the end of 174.

Classification of matter Matter Pure Substance CompoundElementMixture Homogeneous Mixture Heterogeneous Mixture

Pure Substance A substance with constant composition. Can be classified as either an element or as a compound. Examples: Table salt (sodium chloride, NaCl), sugar (sucrose, C 12 H 22 O 11 ), water (H 2 O), iron (Fe), copper (Cu), and oxygen (O 2 ).

Compound A substance that contains two or more elements, in definite proportion by weight. The composition of a pure compound will be invariant, regardless of the method of preparation. Compounds are composed of more than one kind of atom. The term molecule is often used for the smallest unit of a compound that still retains all of the properties of the compound. Examples: Table salt (sodium chloride, NaCl), sugar (sucrose, C 12 H 22 O 11 ), and water (H 2 O).

Element A substance that cannot be separated into two or more substances by ordinary chemical (or physical) means. We use the term ordinary chemical means to exclude nuclear reactions. Elements are composed of only one kind of atom. Examples: Iron (Fe), copper (Cu), and oxygen (O 2 ).

Mixture Two or more substances, combined in varying proportions - each retaining its own specific properties. The components of a mixture can be separated by physical means, i.e. without the making and breaking of chemical bonds. Examples: Air, table salt thoroughly dissolved in water, milk, wood, and concrete.

Homogeneous Mixture Mixture in which the properties and composition are uniform throughout the sample. Such mixtures are termed solutions. Examples: Air and table salt thoroughly dissolved in water

Heterogeneous Mixture Mixture in which the properties and composition are not uniform throughout the sample. Examples: A salad, sand, stir-fry, mixed nuts.

Particle Theory 1. All Matter is made up of extremely tiny particles 2. Each Pure substance has its own kind of particles, different from the particles of other pure substances 3. Particles are always moving. Particles at a higher temperature are generally moving faster, on average than particles at a lower temperature. 4. Particles attract each other

What is matter? Anything that has: Mass Volume So pretty much everything.

Physical Properties Physical Properties- The characteristics of a substance. There are three states of matter, what are they? Solid Liquid Gas All three of these states are physical states of matter.

Physical Properties SolidLiquidGases  retain their shape.  Have a fixed volume  Liquids take the shape of their containers  Have a fixed volume  Gases take the shape of the containers  Volume can change.

Physical Properties Physical property observations can be made using several senses. Sight Smell Touch Taste Sound – This can only give additional information about the others

Physical Properties Colour/ appearance TextureOdourClarityTaste Colourless, white, black, shiny, dull, Fine, course, smooth, gritty Odourless, spicy, sharp, burnt, Transparent, Translucent opaque Sweet, sour, salty, buttery

Typical physical properties Hardness- The measure of the resistance of a solid to being scratched or dented. A harder Material will dent a softer one. Rank the following from hardest to softest. Steel nails, chalk, glass, diamond. Diamond ˃ Steel nails ˃ Glass ˃ Chalk Malleability- The ability to be hammered or bent into different shapes Example Aluminum foil. Brittle – Shatters easily

Typical physical properties Ductility- Can be pulled into a wire. Example: Copper wires Melting and Boiling Points - The temperatures at which substances change states. Ex Water: MP = 0ºC, BP = 100 ºC

Typical physical properties Crystal Form – The solid forms of minerals Example – Sodium chloride = table salt Solubility- The ability a substance to dissolve in a solvent. Eample: salt is soluble in water where pepper is not.

Typical physical properties Viscosity- Refers to how easily a liquid flows: the thicker the liquid the more viscous it is. Density – The amount of mass per unit volume of that matter. (kg / cm 3 )

Chemical properties (3) A chemical property describes the behaviour of a substance as it becomes a new substance

Chemical Properties 1. Combustibility is the ability of a substance to burn. In order to burn a substance requires Oxygen

Chemical Properties Light sensitivity is a chemical property of that can cause new substances to form when light hits it.

Chemical Properties 3. Reacting with an acid is a chemical property where when acid is poured on a substance it produces a gas and bubbles.

Physical changes In a physical change, the substance involved remains the same. The substance may change form or state, however. All changes of state are physical changes. There are other physical changes that are not changes of state. Dissolving is a physical change. When sugar is dissolved it spreads out in the water but the sugar is still sugar. If the water was boiled off there would be sugar left over. Most Physical changes can be reversed.

Chemical changes In a chemical Change the substance is changed into one or more different substances. The new substances have different properties from the original substance. Most chemical changes are difficult to reverse and most cannot be. The new substances are not likely to combine and form the original substance. Often during a chemical change you cannot see the change that has occurred in the substance, but you can observe the results of the change. There are clues that suggest that a chemical change has taken place.

Clues that a chemical change has occurred Change in colour Final product(s) may have a different colour than the colours of the starting material(s). Formation of a solid (precipitate) Final materials may include a substance in a state that differs from the staring material(s): Precipitate

Clues that a chemical change has occurred Formation of a gas Final materials may include a substance in a state that differs from the staring material(s); commonly, a gas Release or absorption of heat Energy (light, electricity, sound or most commonly heat) is given off or absorbed. The change cannot be reversed or it is difficult to.