Boron has two naturally occurring isotopes. Boron 10 abundance is 19.8%. Mass is 10.013 amu. Boron 11 Abundance is 80.2%. Mass is 11.009 amu. Calculate the average atomic mass of Boron.

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.

How many moles of oxygen react with 12 moles of aluminum

Describe at least two advantages and two disadvantages of using hydropower as a source of energy.