Note that butane has two possible isomers but that decane has 75 possible isomers. why does the number of possible isomers go up with an increasing number of carbon atoms?

Awhite powder is added to a solution. the images show observations made before the powder is added, just after the powder has been added, and a little while later. (the liquid in the small beaker is phenol red solution.) what evidence shows that a chemical change has taken place?