Unit 2 - Getting The Most From Reactants Flashcards
Feedstocks
Feedstocks are the reactants for a chemical reaction. Feedstocks are usually extracted from raw materials and then purified before use.
Raw Material
A raw material is a substance available naturally in the Earth’s crust i.e in the ground, sea, atmosphere, or living material
Factors influencing industrial process design
- availability, sustainability and cost of feedstock(s)
- opportunities for recycling
- energy requirements
- marketability of by-products
- product yield
Environmental Considerations
Modern chemical plants are designed to:
* minimise waste
* avoid the use and production of toxic substances
* biodegradable where possible.
Molar Volumes of Gases
The molar volume is the volume occupied by one mole of a gas at a certain temperature and pressure. The molar volume is the same for all gases at the same temperature and pressure. The units are litres per mol (l mol-1).
At room temperature and pressure (abount 25°C adn 1 atmosphere pressure) the molar volume of any gas is about 24 litres per mole.
Limiting and Excess Reagents
Liming agent - the reactant in a chemical reaction which is used up when the reaction stops.
Excess reagent - the reactants which are ‘left over’ at the end of a reaction.
Percentage Yield
The % yield is used to compare the yield of a product actually obtained with what could have been obtained in theory (if all of the reactants were converted with no waste).
Atom Economy
The atom economy is a measure of the % of reactant that become useful products. Atom economy tends to be used more in industry as it tells chemists how efficient a process actually is.
