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.
Properties Of Matter Substance: Is something with a unique and identifiable set of properties. Properties can be qualitative (characteristics, colour) or quantitative (numbers, mass). Qualitative: Green and yellow balls Quantitative: 7 smiley faces There are other types of properties: Physical Property: is a property that can be found without creating a new substance. Example: Density, colour, hardness and melting temperature Physical Properties can either be Intensive or Extensive. Extensive: Depends on the amount of a substance present. Example: Mass and volume are extensive properties. The more substance you have, the greater the mass and volume it occupies. **Extensive 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. **Intensive properties are used to identity a substance**
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.
The Classification of Matter The physical properties possessed by substances are used to classify the substance into two categories: Pure substances 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. A.) Pure Substances: Elements and Compounds 1. Element: Is a substance, which cannot be separated into simpler substances as a result of any chemical processes. (Periodic Table) 2. Compounds: A pure substance made of two or 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)
B.) 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, sugar 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). 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)
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 set of chemicals involved. In general, continued heating of a solid produces the following temperature behaviour.
Separation of Mixtures Compounds can be decomposed into elements. Ex. H2O H2 + O2 Elements cannot be decomposed any further. Ex. Au, Ne, Pt Heterogeneous mixtures are not uniform throughout and thus are easily separated. Homogeneous mixtures can be separated by physical means. Various methods exist to separate mixtures. These include hand separation, filtration, distillation, solvent extraction, recrystallization, gravity separation and chromatography. Hand Separation: - Mechanical mixture can often be separated by hand, a sieve or magnet as various component can easily be seen Filtration: - Used to separate a mechanical mixture of liquids and solids (not solutions) - A filtering apparatus is set up and the liquid is passed through a filter. - The liquid which passes through the filter paper is called the filtrate. The material which remains in the filter paper is called the residue.
Evaporation: - Used to separate a solid-in-liquid solution. - The liquid is evaporated or boiled away and the solid residue will remain. Distillation: - Used to separate a liquid-in-liquid solution. - Requires the different liquids to have different boiling points. - Each component of the mixture is boiled and collected. - The liquid with the lowest boiling point is collected first. Gravity Separation: - Separates substances based on their densities. o Example: Gold panning gold is denser than rock or gravel and thus will stay at the bottom of the pan. - Another type of gravity separation involves using a centrifuge. - A centrifuge spins around very rapidly causing the solid materials to collect at the bottom of the test tube.
Paper Chromatography: - Is a method for analyzing complex mixtures (such as ink) by separating them into the chemicals from which they are made. - Used to separate and identify all sorts of substances in police work. o Drugs from narcotics to aspirin can be identified in urine and blood samples with this method. The retardation factor (Rf) can be mathematically described by the following ratio