How was Bohr's atomic model different from those of previous scientists

Smog is the term used to describe the combination of fog and smoke

What is the molecular formula for a compound that is 46.16% carbon, 5.16% hydrogen, and 48.68% fluorine? the molar mass of the compound is 156.12 g/mol

Which of these would be caused by a chemical change? a) the formation of lava. b) sedimantary rock layering over time. c) metamorphic rock forming from igneous. d) metamorphic rock eroding to form sedimentary rock.