You see lightning before you hear thunder because a) light waves can travel through a vacuum. b) sound waves cannot travel through the air. c) light waves travel faster than sound waves. d) sound waves travel faster than light waves

i think its c
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Abag of potato chips contains 2.00 l of air when it is sealed at sea level at a pressure of 1.00 atm and a temperature of 20.0 deg c. what will be the volume of the air in the bag if you take it with you, still sealed, to the mountains where the temperature is 7.00 deg c and atmospheric pressure is 70.0 kpa? assume that the bag behaves like a balloon and that the air in the bag is in thermal equilibrium with the outside air.