Science LT1 Is
Science LT1 Is
Science LT1 Is
Chemical Properties Reactivity - ability to readily interact chemically with other substances - ex: rusting, giving off odors, changing color, new substance formed, formation of gas/fumes or precipitate, absorption/release of heat Flamability - ability to produce a flame Physical Properties Density - amount of matter in the volume of a substance - intensive property Melting Point - the temp. at which a solid turns into a liquid - intensive property Boiling Point - the temp. at which a liquid turns into a gas - intensive property Thermal and Electrical Conductivity - metals with high conductivity are conductors, those with low conductivity are insulators Malleability - the ability to be morphed without breaking/flattened into thins sheets Ductility - the ability to be stretched into wires or threads - intensive property Intensive Properties - don t depend on the size/amount of the substance - Boiling Point, Melting Point, Density, Taste, Color, Luster, Ductility Extensive Properties - depends on the size/amount of the substance - Mass, volume, length
Separation Techniques
Physical manipulation - manually separating/sorting - Ex: Separating iron nails and screws
Filtration - use of a filtering material that will let only same components through Decantation - separating of the components that form distinct layers (immiscible) - Ex: Pouring one layer out of an oil+water mixture Simple Distillation - components are separated due to the differences in their boiling points - let water evaporate then let it condense Fractional Distillation - special process used for the preparation of fuel and other petroleum products Evaporation - involves heating the mixture to separate the solid residue from the liquid - to get the solute from a solution Use of Magnet Paper Chromatography
Changes in Matter
Physical Change - the molecules of the material undergoing physical change retain their identity. No new substance is formed. The change is only in SIZE, SHAPE, or PHASE of the material Chemical Change - the molecules of the substance involved in a chemical reaction change their identity because a.) the atoms that constitute the molecules may be rearranged, b.) atoms may be removed from the molecule, or c.) atoms may be added to those in the molecule. Hence, a new substance or substances are formed, but the atoms RETAIN their identity.
John Dalton
- first atomic theory: 1. Matter is composed of tiny indivisible particles called atoms. 2. Atoms of a particular element are identical. 3. Atoms of different elements have different masses. 4. Atoms of different elements can join to form compounds.
J.J Thompson
- discovered the electron - concluded that there must be particles within the atom even without confirmation of their existence - proposed the plum pudding model > atoms contain smaller sub-atomic particles (Trivia: Quarks)
Ernest Rutherford
- discovered the nucleus > protons > called the area, nucleus > the atom is mostly empty space > the nucleus may be tiny, but contains 99.99% of the atom s mass
Niels Bohr
- came up with the planetary model of the atom > each electron in an atom has a fixed amount of energy > energy keeps an electron moving around the nucleus within a specific region called energy levels
James Chadwick
- discovered the neutron > nucleus contains neutrons > neutrons have same mass as protons but neutrons have no electrical charge > electrons move constantly around the nucleus
Erwin Schrdinger
- came up with the quantum mechanical model of the atom/Electron Cloud model
Heisenberg
- contributed to Schrodinger s work
Atomic Anatomy
- an atom has 3 basic particles: 1. Proton (nucleus), 2. Neutron (nucleus), and 3. Electron (outside the nucleus) - atomic number = # of protons = * # of electrons (* if atom is neutral) - most atoms are neutral (+ = -), but some atoms gain or lose an electron. When this happens, the atom becomes charged; ION Ex: Fluorine atom + 1 electron FSodium atom 1 electron Na + - mass number = # of protons + # of neutrons - # of neutrons = Mass number Atomic number Element Hydrogen Carbon Oxygen Atomic # 1 6 8 Mass # 1 12 16 # of Protons 1 6 8 # of Electrons 1 6 8 # of Neutrons 0 6 8