Industrial processes are designed to (maximise and minimise)?
Minimise Impact on the Environment
Factors influencing design include?
Sustainability and cost of feedstocksOpportunities for recyclingEnergy RequirementsMarketability of ByproductsProduct Yield
Environmental Considerations Include?
Minimising wasteAvoiding use/production of toxic substancesDesigning products which will biodegrade if appropriate
Balanced equations show (Unit 3)?
Mole ratio of reactants and products
n = (In terms of Mass)
n= (In terms of molar volume)
Volumes of reactant and product gases can be calculated from?
The number of moles of each reactant and product
n = (In terms of concentration)
c x V
The efficiency with which reactants are converted into the desired product is measured in terms of?
The percentage yieldAtom Economy
Percentage Yield =
(Actual Yield x 100)/Theoretical Yield
Given costs for reactants, a percentage yield can be used to?
Calculate the feedstock's cost for producing a given mass of products
The atom economy measures?
The proportion of total mass of all the starting materials succesfuly converted into the desired products
Atom Economy =
(Mass of Desired Products x 100)/ Total Mass of reactants
Reactions with a high percentage yield may have a low atom economy if?
Large quantities of unwanted products are formed
In order to ensure that costl reactants/feedstock are converted into products?
An excess of less expensive reactant/feedstock can be used
As many reactions are reversible products may be?
In equilibrium with reactants
Equilibrium may result in costly reactants?
Failing to be completely converted into products
In a closed system, reversible reactions attain a state of?
What is dynamic equilibrium?
When the rates of forward and reverse reactions are equal
What happens to the concentrations of reactants and products at equilibrium?
Concentrations remain constant but are rarely equal
Manipulation of equilibria for profit
To maximise profits chemists employ strategies to move the position of the equilibrium to favour products
Le Chatelier's principle states?
An equilibrium will move to undo any change imposed upon it by temporarily favouring either the forward or reverse reaction until a new equilibrium position is reached
Le Chatelier's principle can be used to?
Predict the likely effects of altering pressure, altering temperature and addition/removal of reactants/products
Increasing the temperature of an equilibrium micture will favour?
The endothermic reaction
Decreasing the temperature of an equilibrium mixture will favour?
The exothermic reaction
If an equilibrium involving unequal numbers of moles of gas on either side the position will be affected by?
A change in pressure
In an equilibrium an increase in pressure will favour?
The reaction which produces fewer moles of gas
In an equilibrium a decrease in pressure will favour?
the reaction which produces more moles of gas
In an equilibrium increasing the concentration of a reactant will favour?
The forwards reaction
In an equilibrium decreasing the concentration of a reactant will favour?
The backwards reaction
Effect of catalyst on equilibrium
Increases the rate of attainment of the equilibrium but doesn't affect the position of equilibrium
The enthalpy of combustion of a substance is?
The enthalpy change when one mole of the substance burns completely in oxygen
Hess' Law states?
The enthalpy change for a chemical reaction is independent of the pathway taken
Bond enthalpies can be used to estimate the enthalpy change by?
Calculating the energy required to break bonds in reactants and energy released when new bonds are formed in the product
An oxidising agent is?
A substance which gains elecrons
A reducing agent is?
A substance which loses electrons
Elements with low electronegativity values tend to from positive ions so can act as?
Elements with high electronegativity values tend to form negative ions so can act as?
Where in the ECS are the strongest oxidising agents found?
Bottem Left (Come from group 7)
Where in the ECS do the strongest reducing agents come from?
The top right (Come from Group 1)
Examples of strong oxidising agents in acidic solution?
MnO4- and Cr2O72-
Example of a molecule that can act as an oxidising agent
Example of a molecule which can act as a reducing agent
Oxidising agents can be used to kill?
Bacteria and fungi
What does Chromatography do?
Seperates compounds according to their relative affinity for the mobile phase and the stationary phase
Predictors of solubility in the mobile phase
Size of molecules and their polarity
The stationary phase may be?
Paper, silica gel or inert packing material
The Rf value is?
The distance travelled by the sample divided by the distance travelled by the solvent
Retention time is?
The time it takes for the sample to move the full length of the stationary phase
Volumetric analysis involves?
Using a solution of accurately known concentration in a quantitative reaction to determine the concentration of another substance
What is a standard solution?
A solution of accurately known concentration
What is an indicator?
A substance which changes colour at the end-point of a reaction
Substance which acts as its own indicator?
Potassium Manganate(VII) (potassium permanganate)