Bohr's model of the hydrogen atom involved a negative electron orbiting the positive nucleus. What was the fundamental force that supplied the centripetal acceleration to keep the electron in orbit

How many atoms of oxygen are contained in 160 grams of n2o3

Several kinds of bears are found on earth. most bears are brown or black, but one type of bear, the polar bear, is white. what process led to this difference in fur color? explain your answer.

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.