Ok i will make a list questions and answers I remember:
1. What does heterogeneous and catalyst mean (2)
-Catalyst and reactants are at different physical state. Catalyst speeds up the rate of reaction and can be recovered chemically unchanged at the end of the reaction
2. Write equation for reaction Mg + water (2)
- Mg(s) + 2H2O(l) ---> Mg(OH)2 (aq) + H2(g)
3. what is octane number in fuel (2)
- measure of the fuels tendency to auto ignite , the higher the more efficient the fuel
4. Explain how emission spectra are formed (4)..
- Electrons drop to lower energy levels
- emit light/photon
- energy level proportional to freq , e=hv
5. explain why spectra can be used to identify different element in fire works (1 or 2 marks)
- gaps between energy levels are unique for a given element
6. Explain the bond angle in Sio4 (3)
- 4 regions of electron density around the central S atom
- electrons repel to get as far as away as possible/minimize repulsion
- bond angle 109....(I think i put that or did I put 120, hopefully not )
7. What is the other product of reforming (1)
- H2
8. Explain hess law ( 3 or 4)
- the enthalpy change of a reaction is the same independent of the route taken, providing the stat and finish conditions are the same
9. Describe similarities or difference between atomic absorption and emission spectra ( 2 or 4 )
- Difference: atomic emission is coloured lines on black background , absorption black lines on coloured backgrounds
- Similar: - line get closer at higher frequency for both, or I think I put both are line spectra...
10- explain why there is an increase in entropy in equation 2.1 and explain what entropy is (i think.. not sure this is from the mock or real paper)(3)
- entropy is measure of disorder. nor mumber of ways blah blah balh arrange particles
- more moles of gas on the right side so higher entropy/ gas has the highest entropy
11. write equation for cracking of decane to give 3 carbon alkene and something else (1 or 2)
C10H22 + C3H..........
well you can fix and add to it...