So, let's look at an example of equilibrium in the cookie market and see what happens when things change. Let's say the equilibrium price for a chocolate chip cookie is $3. Here's an example of the supply and demand curves, with an equilibrium price of $3, which is at the intersection of the supply and demand curves.
A sigma bond is the end-to-end overlap of the bonding orbitals, usually hybrid orbitals. The sigma bond is a single bond. A pi bond is the side-to-side overlap of unhybridized p-orbitals. A pi bond, along with a sigma bond form a double bond. A triple bond is two pi bonds and a sigma bond. Take a look at this diagram showing a sigma bond and a pi bond, forming a single bond and a double bond. http://metafysica.nl/ethylene01.jpg.
1 In these complexes, there is actual bonding of the reagent to a ring carbon atom and since the pi orbitals now involve only five carbon atoms, there is loss of aromaticity. 2  Experimental evidences, however, suggests that the formation of a sigma complex follows the initial formation of a complex known as a pi complex. In contrast t the sigma complex, the pi complex does not involve actual bonding but the electrophile is held near the pi electron cloud of the aromatic ring.