A catalyst is a chemical substance that affects the rate of a chemical reaction by altering the activation energy required for the reaction to proceed. This is called catalysis.A catalyst is not consumed by the reaction and it may participate in multiple reactions at a time.The only difference between a catalyzed reaction and an uncatalyzed reaction is that the activation energy is different. There is no effect on the energy of the reactants or the products. catalyst is a chemical substance that affects the rate of a chemical reaction by altering the activation energy required for the reaction to proceed. This is called catalysis.
A boater hat, also known as a sennit, basher, skimmer, or sailor, is a distinct type of straw hat. This piece of headwear has a stiff flat top and brim. A wide ribbon or piece of material is often wound around the crown of the hat.
Freebase(0.00 / 0 votes)Rate this definition: Pork pie hat. A pork pie hat is a type of hat made of felt or straw, with a cylindrical crown and flat top. This style of crown is called a telescopic crown, but the hat overall resembles the boater hat. It is short and has an indentation all the way around its top, allowing it to pop upward slightly when worn.