A bell bollard is a style of bollard designed to deflect vehicle tires. The wheel mounts the lower part of the bollard and is deflected by its increasing slope. Such bollards are effective against heavy goods vehicles that may damage or destroy conventional bollards or other types of street furniture. A variant on the bell bollard is the Martello bollard, its sloped shape inspired by the profile of historic Martello towers. Removable bollards Bollards may be hinged at ground level, allowing them to be folded flat to permit vehicles to drive over them.
In stoichiometry calculations, we assume that reactions run to completion. However, when a chemical reaction is carried out in a closed vessel, the system achieves equilibrium. Equilibrium occurs when there is a constant ratio between the concentration of the reactants and the products. Different reactions have different equilibria. Some may appear to be completely products, however, all reactions have some reactants present.
When a system at equilibrium is subjected to change in concentration, temperature, volume, or pressure, then the system readjusts itself to (partially) counteract the effect of the applied change and a new equilibrium is established.hanging the concentration of a chemical will shift the equilibrium to the side that would reduce that change in concentration. The chemical system will attempt to partially oppose the change affected to the original state of equilibrium.