9.5 Industrial Chemistry Flashcards
Explain the effect of changing pressure, volume, concentration and temperature of the Haber process
Le Chatelier’s principle.
Pressure: increase will move equilibrium to the right (Avogadro’s Law)
Volume: relates to pressure
Concentration: force the equilibrium in the direction that will consume excess substance
Temperature: depending on exothermic or endothermic nature of reaction
What factors change the equilibrium constant?
Temperature.
In exothermic: adding heat will decrease K value.
In endothermic: adding heat will increase K value.
Where does the equilibrium lie when K is small
To the left. The reactants are favoured
Where does the equilibrium lie when K is large
To the right. The products are favoured.
Summarise an experiment to model equilibrium reactions
Height of water containers reflects the concentration of products and reactants. As the reaction continued, the rate and concentration of the reactants lowered, whilst the rate and concentration of the products increased.
Identify the qualitative features of equilibrium reactions
- Chemical reactions are reversible
- when equilibrium is established, the rate of the forwards and reverse reaction are the same
- Le Chatelier’s principle summaries the way in which reactions respond to changes
Describe the saponification reaction
A reaction between an ester and hydroxide ion to produce an alcohol and a carboxylate anion (soap). It is the hydrolysis of an ester under alkaline conditions. In the production of soap, saponification occurs to split a triglyceride (for or oil) into a 3 soap molecules and glycerol
Compare the conditions under which saponification occurs in the school laboratory and in industry
Reactants:
S: pure fat or oil, excess NaOh
I: umpire mister of fats and oil, NaOH is regularly monitored
Experiment Conditions: same; high temperature and normal pressure
Remaining salt:
S: washed away
I: reused
Recovery of glycerol:
I: glycerol is recovered from the aqueous residue by distillation
Raw soap:
S: washed with water to remove excess OH and dried
I: carefully washed and dried to meet national standards.
Account for the cleaning action of soap
As a emulsifier, soap has the ability to remove oil or grease particles from objects and disperse them in water. the hydrophobic region of soap attaches to oil particles whilst the hydrophilic region dissolves in water. The soap molecules cover the surface of the oil particle, creating a micelle and lifting it off the object.
Can also clean non-oil-based dirt particles as soap reduces the surface tension of water allowing dirt to easily lift from fabrics. This is because soap molecule on the surface of the water will have their hydrophobic region out of the water, weakening hydrogen bonds between water molecules.
Define emulsion and explain how soap acts as an emulsifier
An emulsion is a picture of an immiscible liquid substances dispersed throughout another liquid substance. These mixtures contain water, oil and an emulsifier, which enables the two immiscible liquids to remain interspersed. Soap acts as an emulsifier by reducing the surface tension of water and attaching to water and oil molecules though their polar and non-polar regions.
Distinguish between the structure of soap and synthetic detergents
Soap: hydrocarbon tail, non-polar and hydrophobic. Anioinic head: carboxylate ion, polar and hydrophillic
Detergents:
- Anionic: anionic head (sulfonate ion)
- Cationic: derivative of ammonium ion head
- Non-ionic: contains many ethoxy groups, ending in an alcohol.
Distinguished between the chemical composition of soap and synthetic detergents
Soap: hydrocarbon tail and carboxylate anion head.
Detergents:
- Anionic: sulfonate ion head
- Cationic: nitrogen atom with alkyl groups attached
- Non-ionic: number of ethoxy groups, ending in an alcohol
Distinguish between the effect of soap and synthetic detergents in hard water
Soap: ineffective as anionic head reacts with positively charged magnesium and calcium cations, forming insoluble salts.
Detergents: do not form salts
- Anionic: effectiveness decreases
- Non-ionic and Cationic: not affected
Identify the uses of synthetic detergents
Anionic: laundry and washing detergents
Cationic: absorb onto hair and material fibres, biocides. used as disinfectant, hair conditioner, fabric softener
Non-ionic: does not produce foam. Used in pesticides, cosmetics, paint.
Recount the method of producing soap
- Set up water bath
- Place NaOH and ethanol.water picture into a beaker. Stir
- Mix two solutions together
- Place in water bath until mixture looks thick and creamy
- Add water
- Pour mixture into saturated NaCl solution.
- Remove soap layer, rinse and dry.
Compare fats and oil
Fats: solids at room temperature. Saturated molecules, so have a higher BP due to strong intermolecular bonds
Oils: liquids at room temperature. They are unsaturated molecules, so have a lower BP due to weaker intermolecular bonds.
Fats and oils are esters of glycerol (1,2,3-propanetriol)
Glycerol + 3 fatty acids = fat/oil + 3 water
Evaluate the environmental impacts of using soaps and detergents
- Soap impacts environmental minimally sit is biodegradable; broken down into water and carbon dioxide by microorganisms
- Initial anionic surfactnats were not biodegradable so waterways become contaminated with foam. As a result, liner chained alkylbenzene sulfonates were later developed, which have a higher biodegradability.
- Cationic: biocidal property means that lager volumes can kill microorganisms, such as bacteria which assists in the decomposition of sewerage. At lower concentrations, bacteria can decompose it.
- Non-ionic: bind to proteins in the phospholipid bilayer of cells, increases the permeability of membranes, so amino acids, ions and salts are lost from the cell.
Identify the original source of rubber and its disadvantages
Rain forest plantations in tropical areas (Malay and Burma). Whilst it was a renewable resource, it was labor intensive and required large areas of land.
Identify the replacement material for rubber and why it was necessary
During WWII, the demand for rubber increased due to the increased production of vehicles. Due to interrupted access to supplies, a synthetic polymer was made to replace rubber. Following WWII, it was continually used as natural resources were unable to keep up with increasing demands. Synthetic polymer is cheaper, easily manufactured and long-lasting.
