Change in measurable Change in time 0.2 – 0.05 = /20 = mol l -1 s -1

= Energy at end – energy at start = 40 – 50 = -10kJ mol -1

What is the activation energy for the reverse reaction?

= = 30 kJmol -1

Draw a line to show effect of a catalyst

What is the activation energy of the forward reaction?

= = 40 kJmol -1

Draw a line to show the effect of an increase in temp In some reactions - apart from heat energy, what other source of energy can be used to increase the number of particles over E A ?

Draw a line to show the effect of an increase in temp In some reactions - apart from heat energy, what other source of energy can be used to increase the number of particles over E A ? Give them a hint “photosynthesis”. Answer : LIGHT ENERGY

Catalysts What types of catalysts do you get and explain what their names mean?

Catalysts What types of catalysts do you get and explain what their names mean? Heterogeneous (different physical state) Homogeneous (same physical state)

Catalysts How do heterogeneous catalysts work? Catalyst Active site

Catalysts How do heterogeneous catalysts work? Reactant molecules adsorb onto the active site of the catalyst. Bonds between atoms within the reactant molecules weaken. New bonds form between atoms of the product. Product desorbs from active site. Active site free for new reactant molecules Catalyst Active site

Catalysts What type of petrol must be used in a car fitted with a catalytic convertor? Why?

Catalysts What is the catalyst in a catalytic convertor? What type of petrol must be used in a car fitted with a catalytic convertor? Why? Transition metals (platinum, rhodium and palladium) Unleaded petrol, because the lead would poison the active sites on the catalyst. Poisoned active sites cannot adsorb new reactants

What is the trend in ionisation energy going down a group? Explain

Ionisation energy decreases. The electron being removed is in an energy level further away from the nucleus AND there is a shielding effect from the inner electrons.

What is the trend in covalent radius going across a period? Explain

The covalent radius decreases due to increased nuclear charge having a greater pull on the electrons.

Name the types of bonding: electrostatic force of attraction between.. positively charged ions and delocalised electrons positively charged nuclei and negatively charged shared electrons oppositely charged ions

Name the types of bonding: electrostatic force of attraction between.. positively charged ions and delocalised electrons – metallic positively charged nuclei and negatively charged shared electrons – covalent oppositely charged ions – ionic

Give examples of elements with Monatomic structure Covalent molecular structure Covalent network structure Metallic

Give examples of elements with Monatomic structure – He, Ar, Kr, Xe, Rn Covalent molecular structure – S, P and C (fullerene) Covalent network structure – B, C, Si (carbon – graphite and diamond) Metallic – Fe, Cu…any metal

Why can metals and graphite conduct electricity? Describe the structure of a fullerene

Why can metals and graphite conduct electricity? – Because they have delocalised electrons. Describe the structure of a fullerene. – A large spherical shaped carbon molecule

Explain why H 2 O, HF and NH 3 show unusual properties.

Due to the presence of hydrogen bonds. These relatively strong INTERMOLECULAR bonds mean molecules require more energy to become gaseous. They arise between molecules which have H bonded to N,O and F

4 moles 1 mole of molecules X 5 = 5 moles of atoms 0.5 moles of molecules X 2 = 1 mole of atoms 1 mole of molecules X 4 = 4 moles of atoms 0.5 mole of atoms Which one / ones will have the greatest volume?

4 moles 1 mole of molecules X 5 = 5 moles of atoms 0.5 moles of molecules X 2 = 1 mole of atoms 1 mole of molecules X 4 = 4 moles of atoms 0.5 mole of atoms Which one / ones will have the greatest volume?

What is the trend in melting point going down group 0. Explain.

Melting point increases. (Increased mass results in increased Van der Waals’ forces. Thus more energy is required for atoms to become gaseous.)

What type of bonds are present in these molecules? What type of molecules are these? Which one could be used as a solvent for hexane (a non polar molecule)?

CCl 4 –non polar molecule (perfect symmetry) CCl 4 could be used as a solvent for hexane (a non polar molecule)? CHCl 4 –polar molecule (doesn’t have perfect symmetry) ALL of the bonds are polar since the atoms all have different electronegativities.

What are Van der Waals’ forces?

Van der Waals’ forces are a result of electrostatic attraction between temporary dipoles and induced dipoles caused by movement of electrons in atoms and molecules.

What is a hydrogen bond?

Strong intermolecular force of attraction. A Hydrogen bond is a special example of a permanent dipole – permanent dipole intermolecular force of attraction. It is caused by the large difference in electronegativity between hydrogen and nitrogen, oxygen or fluorine.