Write equastions, using displayed formula, to show the conversionn of but-1-ene into: a) polybut-1-ene
b) 1,2-dibromobutane

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

d.) circle motion requires a force to give it a centripetal acceleration.

chemical digestion occurs in the stomach were hcl and pepsin forms chyme, the mouth in which salivary amylase breaks down starch to form bolus, and the small intestine specifically the duodenum.