CEM 141 - Exam 2 Questions And Answers Rated A+ New Update Assured Satisfaction

mole - 6.022 x 10^23 things number of particles that allows us to convert from the molecular to the macroscopic level limiting reactant/reagent - amount of one of the reactants which limits how much product can be formed. smallest amount. percent yield - actual/theoretical x 100 electromagnetic radiation - wavelength - The distance between two corresponding parts of a wave. seconds/wave. 1/frequency. measured in m amplitude - Height of a wave frequency - waves/second. 1/wavelength. measured in Hz Constant (c) - 3 x 10^8 m/s. c=(wavelength)(frequency) constructive interference - The interference that occurs when two waves combine to make a wave with a larger amplitude = brighter destructive interference - The interference that occurs when two waves combine to make a wave with a smaller amplitude = darker diffraction - The bending of a wave as it moves around an obstacle or passes through a narrow openingmodels of light - light as a wave/particle photoelectric effect - The emission of electrons from a metal when light shines on the metal. why is light considered a wave (evidence) - diffraction, interference why we consider light a wave (claim, evidence, reasoning) - claim-light is a wave evidence- diffraction, interference reasoning- light acts the same as waves as demonstrated in diffraction and interference. why is light considered a particle - photoelectric effect. there is a threshold frequency below which no electrons are emitted from metal when light is shined . if light were a wave, the intensity should increase the energy and eject electrons. photon - Einstein postulated light must come in packets (particles or quanta) energy - E=hv h=6.626x10^-34 J/s visible spectrum - light from the sun (white light) can be separated by a prism (first done by Newton) atomic emission spectrum - light from one particular element does not contain all the colors of the spectrum, only few wavelengths. The discontinuous line spectra of light produced when excited atoms return to their ground state and emit photons of a certain frequency. atomic absorption spectrum - The characteristic line spectrum that occurs as a result of energy being absorbed by individual elements. Black lines on a continuum (coloured) ra - shows light at specific wavelength and energies Bohr model of atom - explained emission/absorption spectra by invoking discrete energy levels characterized by quantum numbers (n). photons of e/m energy are emitted from atoms as electrons move from one energy level to another. ONLY WORKS FOR HYDROGEN