C5: Monitoring and controlling chemical reactions

C5.1 Monitoring chemical reactions

**CM5.1i calculations with numbers written in standard form when using the Avogadro constant**

CM5.1ii provide answers to an appropriate number of significant figures

CM5.1iii convert units where appropriate particularly from mass to moles

CM5.1iv arithmetic computation, ratio, percentage and multistep calculations permeates quantitative chemistry

CM5.1v arithmetic computation when calculating yields and atom economy

CM5.1vi change the subject of a mathematical equation

** C5.1a explain how the concentration of a solution in mol/dm3 is related to the mass of the solute and the volume of the solution**

C5.1b describe the technique of titration

**C5.1c explain the relationship between the volume of a solution of known concentration of a substance and the volume or concentration of another substance that **react** completely together to include titration calculations**

**C5.1d describe the relationship between molar amounts of gases and their volumes and vice versa**

**C5.1e calculate the volumes of gases involved in reactions using the molar gas volume at room temperature and pressure (assumed to be 24dm3)**

**C5.1f explain how the mass of a solute and the volume of the solution is related to the concentration of the solution**

C5.1g calculate the theoretical amount of a product from a given amount of reactant

C5.1h calculate the percentage yield of a reaction product from the actual yield of a reaction

C5.1i define the atom economy of a reaction

C5.1j calculate the atom economy of a reaction to form a desired product from the balanced equation

**C5.1k explain why a particular reaction pathway is chosen to produce a specified product given appropriate data to include data such as atom economy (if not calculated), yield, rate, equilibrium position and usefulness of by-products**

C5.2 Controlling reactions

CM5.2i arithmetic computation, ratio when measuring rates of reaction

CM5.2ii drawing and interpreting appropriate graphs from data to determine rate of reaction

CM5.2iii determining gradients of graphs as a measure of rate of change to determine rate

CM5.2iv proportionality when comparing factors affecting rate of reaction

C5.2a suggest practical methods for determining the rate of a given reaction

C5.2b interpret rate of reaction graphs to include 1/t is proportional to rate and gradients of graphs

C5.2c describe the effect of changes in temperature, concentration, pressure, and surface area on rate of reaction

C5.2d explain the effects on rates of reaction of changes in temperature, concentration and pressure in terms of frequency and energy of collision between particles

C5.2e explain the effects on rates of reaction of changes in the size of the pieces of a reacting solid in terms of surface area to volume ratio

C5.2f describe the characteristics of catalysts and their effect on rates of reaction

C5.2g identify catalysts in reactions

C5.2h explain catalytic action in terms of activation energy to include reaction profiles

C5.2i recall that enzymes act as catalysts in biological systems

C5.3 Equilibria

CM5.3i arithmetic computation, ratio when measuring rates of reaction

CM5.3ii drawing and interpreting appropriate graphs from data to determine rate of reaction

CM5.3iii determining gradients of graphs as a measure of rate of change to determine rate

CM5.3iv proportionality when comparing factors affecting rate of reaction

C5.3a recall that some reactions may be reversed by altering the reaction conditions

C5.3b recall that dynamic equilibrium occurs in a closed system when the rates of forward and reverse reactions are equal

**C5.3c predict the effect of changing reaction conditions on equilibrium position and suggest appropriate conditions to produce as much of a particular product as possible to include Le Chatelier’s principle concerning concentration, temperature and pressure**