SCIENCE

• Physical properties of matter

  Characteristics that can be observed without changing the substance into another substance
• Melting point


  The temperature at which a substance changes state from solid to liquid. At the melting point the solid and liquid phase exist in equilibrium.
• Boiling point


  The temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor
• Odor


  Caused by one or more volatilized chemical compounds that are generally found in low concentrations that humans and animals can perceive by their sense of smell
• Color


  The visual perceptual property corresponding in humans to the categories called blue, green, red, etc. Color derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors
• Taste


  The sensation of flavor perceived in the mouth and throat on contact with a substance
• Solubility


  The ability of a substance, the solute, to form a solution with another substance, the solvent
• Density


  A physical property of matter that expresses a relationship of mass to volume
• Hardness


  The ability of a material to resist deformation, which is determined by a standard test where the surface resistance to indentation is measured
• Softness


  The quality of not being hard or firm: the quality of not being rough or hard to touch
• Volatility


  A material quality which describes how readily a substance vaporizes
• Ductility


  A physical property of a material which is associated with the ability to be hammered thin or stretched into wire without breaking it
• Malleability


  The ability to be distorted below compression. It is a physical property of metals by which they can be hammered, shaped and rolled into a very thin sheet without rupturing
• Viscosity


  The resistance of a fluid (liquid or gas) to a change in shape or movement of neighbouring portions relative to one another
• Physical state


  The condition that characterizes the form of a substance (gas, liquid, or solid) at a given temperature and pressure
• Heat conductivity


  The rate at which heat is transferred by conduction through a unit cross-section area of a material, when a temperature gradient exits perpendicular to the area
• Electrical conductivity


  The measure of the amount of electrical current a material can carry or its ability to carry a current
• Chemical properties of matter


  Properties that can be measured or observed only when matter undergoes a change to become an entirely different kind of matter
• Flammability


  How easily something will burn or ignite
• Toxicity


  How dangerous a chemical is to your health, a particular organ, another organism, or to the environment
• Acidity


  Acids are sour in taste. Acids react with carbonates and hydrogen carbonates to form a salt, water, and carbon dioxide gas. Extremely active metals such as Potassium (K), Calcium (Ca), Sodium (Na), etc tend to explode when combined with acids. Weak Acids like Carbonic Acid doesn't act with any metal at all
• Reactivity


  The ability of a chemical to react with another chemical to form a new substance
• Heat of combustion


  The amount of energy that is released as heat when a substance is burned with oxygen
• Pure substances


  Forms of matter that have definite and unchanging chemical composition. They can be classified as elements or compounds
• Elements


  Substances that are made up of only one type of atom
• Abundance of elements in the Earth's crust, water, and atmosphere in percent by mass

  • Calcium
  • Phosphorus
  • Magnesium
  • Sodium
  • Chlorine
  • Potassium
  • Sulfur
  • Iron
  • Zinc
  • Iodine
• Compounds


  Substances that are made up of more than one type of atom
• Mixtures


  Made up of two or more substances that are physically combined
• Homogenous mixtures


  Have only one phase or uniform appearance throughout, and any portion of the sample has the same properties and composition
• Solution


  A homogenous mixture of two or more substances in variable composition
• Separating mixtures by physical means

  1. Evaporation

  2. Sublimation

  3. Distillation

  4. Decantation

  5. Crystallization

  6. Use of sieves

  7. Use of magnets
• Heterogenous mixtures


  Are made up of more than one phase or of different parts and can be separated by physical means
• MELTING


  Physical change of a solid to a liquid by the addition of energy as heat
• FREEZING


  Change of state in which a liquid becomes a solid as heat is removed
• EVAPORATION


  Change of a substance from a liquid to gas
• CONDENSATION


  Change of state from a gas to liquid
• SUBLIMATION


  Process in which a solid changes directly into gas
• ATOMIC THEORY OF MATTER

  Proposed by John Dalton (1766-1844), an English school teacher and amateur meteorologist
• All matter is composed of tiny, indivisible particles called atoms
• All atoms of a particular element are identical, but the atoms of one element differ from the atoms of any other element. Each element has unique atoms