How much chalcopyrite had be mined to produce 100 pennies if each reaction involving copper proceeded in 63.00 % yield?

answer

fusion: the energy source of stars. the energy released from the collapse of the gas into a protostar causes the center of the protostar to become extremely hot. when the core is hot enough, nuclear fusion commences. fusion is the process where two hydrogen atoms combine to form a helium atom, releasing energy.

hope it

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

im pretty sure its b