MATTER: CLASSIFICATION AND PROPERTIES

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1 MATTER: CLASSIFICATION AND PROPERTIES Chemistry: Is the science concerned with the properties, composition and behaviour of matter. Matter: Anything that has mass and occupies space. (volume) (Matter is what makes up the universe) Matter exists in three (3) common states or phases : solid, liquid and gas all with a unique set of properties, which allows a given substance to be classified as a solid, liquid or gas.

2 Solids: Have a fixed shape and volume Very small changes in volume when heated or subjected to pressure. Molecules have vibrational energy All the particles are packed into a given volume in a highly organized and rigid manner, which requires particles to be in direct contact with each other. (Therefore not compressible) Example: The volume occupied by 28.0 g off solid nitrogen is 27.3 ml Ice

3 Liquids: Has a fixed volume, but takes the shape of its container Molecules are close together, but are able to tumble over top of one another. Molecules display both vibrational and rotational energy. (Rotational energy causes a molecule to rotate around one of its axis think of it as spinning around and around) The particles remain in close contact with each other but have sufficient room to slide past one another and therefore are not compressible. Example: The volume occupied by 28.0 g of liquid nitrogen is 34.6 ml Water

4 Gases: Takes the shape and volume of its container Highly compressible Volume is drastically changed by changes in temperature and pressure Spaces between molecules is very large The particles are widely separated and only contact each other during collisions. Because the wide separation of particles can be decreased, gases are compressible. Example: The volume occupied by 28.0 g of gaseous nitrogen at room temperature is ml (24L) The table below summarizes the properties of solids, liquids and gases with respect to volume and movement. Solid Liquid Gas Volume Occupied Small Small Large Movement allowed in substance Small Small Very Large

5 Propert ies Of Matter Substance: Is something with a unique and identifiable set of properties. Properties can be qualitative (characteristics, colour) or quantitative (numbers, mass). There are other types of properties: A Physical Property of a substance is a property that can be without creating a new substance. Example: Density, colour, hardness and melting temperature Physical Properties can either be Intensive or Extensive. found Extensive: Depends on the amount of a substance present. Example: Mass and volume are extensive properties. The more substance you have, the greater the masss and volume it occupies. **Extensivee properties are NOT used to identify substance. For Example, a 5 g chunk of material could be dirt or gold** Intensive: Depends solely on the nature of the substance, and NOT on how much of substance is present. Example: Density and melting temperature are intensive properties. Pure gold always has the same density and melting temperature, regardless of amount. **Intensivee properties are used to identity a substance**

6 A Chemical Property is the ability of a substance to undergo chemical reactions and change into new substances, either by itself or with other substances. Combustible: Burns with oxygen. Example: One chemical property of hydrogen is its ability to burn in air and produce water; another is its ability to react with chlorine gas and produce hydrogen chloride. More Definitions Hardness: Is the ability of a solid to resist abrasion or scratching. Malleability: Is the ability to be rolled or hammered in to thin sheets. Ductility: Is the ability to be stretched or drawn into wires. Lustre: Is the manner in which a solid surface reflects light. Lustre s can vary from metallic to glassy, oily, pearly, silky or dull. Viscosity: Is the resistance of a fluid to flow.

7 The Classifi ication of Matter The physical properties possessed by substances are used to classify the substance into two categories: Pure substance es and Mixtures. Some definition you may already know Element: Is a substance, which cannot be separated into simpler substances as a result of any chemical process. The periodic table! Atom: Smallest possible unit of an element which retains the fundamental properties of the element. Molecule: Cluster of two or more atoms held together strongly by electrical forces. Ion: Atom or molecule, which possesses an electrical charge. Particle: General term used to describe a small bit of matter such as an atom, molecule or ion. Pure Substances: Elements and Compounds Element: Is a substance, which cannot be separated into simpler substances as a result of any chemical processes. (Periodic Table) Compounds: a substance that has an unchangeable composition. A pure substance made of two orr more types of atoms. Only one type of molecule is present in a compound. (Example: Salt (Sodium Chloride), Water = H 2 O, Sugar, Copper (II) Chloride)

8 Mixtures: Is a system made up of two or more compounds, such that the relative amounts of each substance can be VARIED. (Example: salt water, granola, milk) Homogeneous: Is a substance consisting of only one phase. (Example: air, water) Looks consistent. Heterogeneous: Is a substance consisting of more than one phase. You can see the different parts. 1. Mechanical Mixture: Is a heterogeneous mixture of two or more substances. (Example: gravel, sand and iron fillings) 2. Solutions: Is a homogeneous mixture of two or more substances. There are several different types of solutions: Type of Solution Gas in Gas Gas in Liquid Liquid in liquid Solid in Liquid Solid In Solid Example Air (oxygen, nitrogen) Pop Water and Alcohol Salt dissolved Water Alloys (metals melted together) Now solution can be broken down into two separate definitions Solvent: Is the component in a solution, which exists, in the greater quantity. (Example: When salt is dissolved in water, WATER is the SOLVENT). Solute: Is the component in a solution, which exists, in the smaller quantity. (Example: When salt is dissolved in water, SALT is the SOLUTE).

9 3. Suspension: Is a heterogeneous mixture between solids and liquids where the solids will eventually settle if left undisturbed. (Example: dirt in water) 4. Colloid: Is a homogeneous mixture between solids and liquids where the solids will not settle if left undisturbed. (Ex. Mayonnaise)

10 Chemical and Physical Changes of Matter Chemical Change: Is a change in which new substances are formed. A chemical change produces a set of chemicals with is different from the set of chemicals which existed before the change. 1. light or heat is given off 2. bubbles form (gas) 3. colour change 4. can be hard to reverse 5. a ppt forms (ppt= precipitate = solid) Physical Change: Is a change in the phase of a substance, such that no new substances are formed. A physical change does not change the sett of chemicals involved. In general, continued heating of a solid produces the following temperature behaviour. Temperature S Melting S L Freezing L L Boiling G G Condensing Heat entering the system