3.2.1/3.2.2/3.2.3 Enthalpy changes, reaction rates and chemical equilibrium GapFill

Reactions that give out or take in heat energy are said to be  extrathermic and intrathermicexothermic and endothermicintrathermic and extrathermicendothermic and exothermic, respectively. Measuring the change in heat energy associated with a reaction relies on recording the temperature change in a substance of known mass and  definitediscreteparticularspecific heat capacity. The heat released or absorbed during a process is closely tied to a quantity called the enthalpy change, represented by the symbol Δ  CJEH. Often, enthalpy changes are measured under 'standard conditions', represented by a   s#*⦵ symbol.  This term refers to a stated temperature, usually 298 K, and a pressure of  100 kPa1000 kPa100 Pa1000 Pa, with an element's physical state under such conditions called its 'standard state'.

The rate of a chemical reaction is determined by the frequency with which reactant particles collide with both the correct orientation and with sufficient energy, the  initiationactuationdrivingactivation energy. Species that increase the rate of reaction without being used up themselves are called   cataphyllscatalystscatalexescataphores.

The equilibrium constant for a reversible reaction, written in terms of the concentrations of the reactants and products, is denoted by the symbol   KcDcRcEc. More specifically, it is the product of the concentrations of the products  ortimesto the power ofdivided by the product of the concentrations of the reactants, with each species' concentration raised to the power of its stoichiometric coefficient in the chemical equation. The concentration of a given species X is always written in units of mol dm⁻³, and is represented by  /X/[X]~X~{X}. For now, you will only be expected to write expressions for the equilibrium constants of reactions where all the reactants and products are in the same phase, which are described as   orthogeneousparageneousheterogeneoushomogeneous. The effect of a change in conditions on the position of an equilibrium can be predicted using  Le Chatelier'sLaplace'sPasteur'sGrignard's principle.