CLEP Biology 2x - Biology study of life Atoms all living things are composed basic building blocks Neutrons atom neutral charge Proton atom positive

CLEP Biology 2x - Biology study of life Atoms all living...

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Biology – study of life Atoms- all living things are composed basic building blocks Neutrons atom – neutral charge Proton atom – positive charge Electrons – negatively charged Greatest to smallest – cells, organelles, molecules, atoms Isotope – atom with same number of protons but different number of neutrons Hydrogen atoms – always have 1 proton (autonomic number of 1) Protons – number is always constant with each element, neutrons can vary Atomic mass - sum of neutrons and protons in the atom Periodic table – describes all know elements, their name, symbol, atomic number and atomic mass Valence shell – outermost shell of the electron in any atom (atoms are stable when they hold 8 electrons) Covalent bond – two atoms share electrons H-H Double covalent bond – C=C – two pairs electrons are shared Triple covalent bond N= N – three pairs of electrons are shared Ionic bond – one atom transfers one electron to another resulting in positive charge for the atom that lost the electron and a positive charge for the atom that gained the electron Ions – when atoms gain or lose an electron Electronegativity – when atoms exert pull on the electrons of surrounding atoms Polar covalent bond – (water) when a partial positive and negative charge on opposite sites of the molecule are pulled together Hydrogen bond – in a molecule with polar covalent bonds a wek electromagnetic attraction that bonds other polar molecules together Carbon, Hydrogen, nitrogen and oxygen are called living or organic compounds Products – when reactants interact with each other and combine ( C6H12O6+6O2 = 6H2O+6CO2) No material is added or removed just rearranged Decomposition – molecules are broken down into smaller parts and energy is release Exothermic – any chemical reaction that releases energy Synthesis reactions – smaller molecules are joined to form bigger molecules Endothermic – trap energy to be released later Cohesion – hydrogen bonds that constantly form between water molecules to cause water to sick to itself Adhesion – water molecules sticking to other substances Surface tension – allows insects to walk on the surface of water Water expands when frozen - moves from liquid to solid, hydrogen bonds arrange the molecules into a hexagonal structure that is less dense than water in liquid state, extra space causes water to float PH scale measures how acidic or basic a substance is 0-14 (7 neutral) Solvent – dissolving agent (water) Solute – the substance being dissolved (salt, sugar, etc,) Hydrophilic – alcohol, sugar and water are hydrophilic (water-loving) they mix freely - Polar and ionic substances dissolve in water Hydrophobic – something that repels water (oil)– Nonpolar or nonionic substances do not interact with water Hydrolysis – water breaks the bond between two parts of molecule and is itself split in the process Dehydration reaction – water is removed in order for two molecules to join together (condensation reaction)
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