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15 Cards in this Set

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How does adding a catalyst increase rate of reaction?

- Catalyst provide alternative pathway for the reaction with lower activation enthalpy


- More particles will now exceed activation enthalpy


- More successful collisions per unit time = higher (faster) rate



Define Dynamic equilibrium

- The rate of the forward reactions and reverse reactions are equal in a closed system


- The concentration of a reactants and products no longer change

What affect does increasing pressure has on the equilibrium position?

Increasing the pressure pushes the equilibrium position to the side with fewer moles of gas which is the left, hence less product is made

What affect does rising temperature has on the equilibrium position

- Rising temperature pushes the equilibrium position in the endothermic direction ( the reverse reaction is endothermic ) which is the left. less product is made

The best condition for making x is very high pressure, suggest why only medium pressure is used in reality?

- Thick walled apparatus to cope with pressure very costly


- Large energy costs in creating/keeping high pressure using heavy duty pumps

Describe the ways to reduce CO2 levels

- Burn less fossil fuels and use non carbon based alternatives such as geothermal or tidal


- Plant more tress to increase photosynthesis


- Pumping it under pressure to the deep ocean floor


- Pumping it under pressure into disused oil/gas wells

Why is carbon capture and storage not widely used?

- Apparatus and energy costs of pumping co2 at pressure to bottom of deep sea makes it very expensive


- concerns that CO2 may harm marine life in deep oceans by increasing acidity of water

What industrial process produce carbon dioxide?

- Refining oil


- Generating electricity


- Making iron/steel


- fermentation

Explain in terms of intermolecular bonds why bromine has higher b.p. than chlorine

- Non-polar molecules have instantaneous dipole-induced dipole intermolecular bonds


- Random movement of electrons in molecules creates uneven distribution of charge.


- This induces a dipole in a neighbouring molecule leading to an attraction


- Molecules with more electrons (Br2) will form stronger intermolecular bonds


- more energy will be needed to overcome/break the stronger intermolecular bonds so b.p. is higher

What is E/Z isomerism?

- the c=c double bound prevents rotation


- there must be two different groups on each carbon of the carbon-carbon double bond

What is a radical?

Particles( species) with an unpaired electron

Why is the molecule CF3Cl polar?

- C-Cl and C-F bonds have different polarities


- The dipoles/charges do not cancel out or centre of positive of positive and negative charges don't coincide


- Or there is a greater (partial ) negative charge on the F side of the molecule

Explain the shape of the SO2 molecule and give the bond angle

- There are 3 regions electron density around the central atom S


- Regions of electron density repel as far part as possible to minimise repulsion


- the shape is bent and bond angle is 120

What is meant by heating under reflux?

- Boiling a liquid reaction mixture with a a vertical condenser to prevent products and reactants from boiling away

What is meant by the term homogeneous catalyst?

- Catalyst provides alternative pathway for reaction with lower activation enthalpy


- Is chemically unchanged at the end of the reaction


- Homogeneous means catalyst is in same state as reactants