Suppose there are two known compounds containing the generic elements X and Y. You have a 1.00 g sample of each compound. One sample contains 0.30 g of X and the other contains 0.39 g of X.

in scientific notation, the value of the  speed of light in a vacuum

  will be written as 2.995 * 10^8. when this value is represented in the form of

  a * 10^b, then, a = 2.995 and b = 8.

the value of the speed of light in a vacuum given above can also be rounded up to approximately 300000000. in this case, the scientific notation will be written as 3 *10^8.

answer///carbon;