Unit 3 - Chemistry In Society Flashcards
If a reaction is said to be at equilibrium, what does that mean?
The rate of the forward reaction equals the rate of the reverse reaction.
In regards to equilibrium, what happens when you increase the pressure?
The equilibrium will shift to the side with the least amount of gaseous moles.
How would you increase the pressure in a system?
By decreasing the volume of container or by increasing the concentration.
What will the effect be on equilibrium if you increase the temperature?
Increasing the temperature shifts the equilibrium in favour of the endothermic reaction.
What is enthalpy of combustion?
The enthalpy of combustion of a substance is the enthalpy change when one mole of the substance runs completely in oxygen.
What is the enthalpy of solution?
The enthalpy of solution of a substance is the Whaley change when one mole of the substance dissolves in water.
What is a displacement reaction?
A displacement reaction is where one metal displaces another metal from a solution of its salt. If a more reactive metal is placed in solution containing ions of a less reactive one, a displacement will occurr.
How would you write the balanced ion-electron for the oxidation or reduction of an oxyanion?
1) Balance the oxygens by adding H2O (Water)
2) Balance the hydrogens by adding H^+ ions.
3) Balance the charge by adding electrons ( e^-)
How do you calculate the RF value in chromatography?
RF = Distance travelled by component/ distance travelled by solvent.
What are the 7 principles of design process?
- Availability of feedstocks
- Cost of the feedstock
- Sustainability of the feedstock
- Opportunities for recycling
- Energy requirements
- Marketing ability of by-products
- Product yield / Atom economy
What is a standard solution?
A standard solution is one in which the concentration is accurately known.
What are the steps to making a standard solution?
1 - Accurately weigh mass of solid required
2 - Dissolve solid in as little water as possible
3 - Transfer solution into a volumetric flask
4 - Wash all apparatus with distilled water and trasnfer washing to the flask
5 - Fill to the graduation mark and invert several times to mix.
What are the steps to calculating an excess question?
1 - Mole ratio between the two products
2 - Calculate number of moles for both products
3 - Relook at mole ratio and work out which product is the limiting reactant and which product is in excess.
