41. explain the difference between homogenous and heterogeneous mixtures. 42. what is the difference between atomic number of an element and its mass number? 43. the big bang theory does not try to explain how the universe was created. what does it explain? 44. why do isotopes of elements have the same atomic number but different mass numbers? 45. why does earth’s moon lack an atmosphere?

Hunter is in lab. he clears a spot on his lab bench to start working. he also puts his lab coat and goggles on. he then identifies where all of the safety equipment is. he notices his station is next to the fume hood, which ventilates the chemicals stored there. the noise of the fume hood was bothersome, so hunter turned it off. which could be an error in his set-up? he should not turn off the fume hood.  he should wait to put on his coat until after the directions are given.  he should wait to put on his goggles until after the directions are given.  he should not sit next to the fume hood.