Praxis II Middle School Science 5440 Latest Update Graded A+

Praxis II Middle School Science 5440 Latest Update Graded A+ "Zeroth" Law of Thermodynamics If systems 1 and 2 are both in equilibrium with 3, then 1 and 2 are also in equilibrium with each other. 1st Law of Thermodynamics Matter and energy are conserved (energy in = energy out) in a closed system. 2 elements - liquid at room temperature Hg, Br 2nd Law of Thermodynamics Entropy always increases in a closed system. Not all energy is transferred; some is "lost" as heat. 3rd Law of Thermodynamics entropy approaches equilibrium with low temperatures (but absolute zero is not possible). 9 elements naturally exist as diatomic molecules (at room temperature) H2 O2 N2 F2 Cl2 I2 Br2 ("HONF - Cliber") Abyssal plain an area where sea floor spreading has created flat plains like area under water Acids low pH (1-6), high concentration of H+ ions, turns blue litmus paper red Agents of erosion water, wind, ice, waves, gravity Air density At sea level, air density is around 1.2 kg m-3 Air density decreases with altitude Air pressure the cumulative effect of the push exerted by each molecular collision on its surroundings Pressure is a force distributed over an area. The unit of Pressure is N m-2, or Pascal Alfred Wegener proposed continental drift (1915) Atoll An atoll is a ring-shaped coral reef or island that surrounds a body of water called a lagoon. Atolls develop with underwater volcanoes, called seamounts. Atom smallest unit of matter, mostly empty space; contains nucleus (protons and neutrons) and orbiting electrons. Atomic # # protons (= #electrons) Atomic mass protons + neutrons Bases high pH (8-13), low concentration of H+ ions, turns red litmus paper blue Buffers resist change in pH value Chemical change (examples) rusting, fermentation, burning Chemical Properties (examples) reactivity, pH, flammability Chemical weathering oxidation, hydrolysis