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.
The reaction rates of the forward and backward reactions are generally not zero, but equal. Thus, there are no net changes in the concentrations of the reactant(s) and product(s). Such a state is known as dynamic equilibrium.he equilibrium concentration position of a reaction is said to lie far to the right if, at equilibrium, nearly all the reactants are consumed. Conversely the equilibrium position is said to be far to the left if hardly any product is formed from the reactants.