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And CHEMISTRY P1 is going to be a BREEZE.

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Zizu1992

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Hey Everybody, I am going to solve all the Past Papers most of them here under this topic with reasoning till tomorrow. So you guys can review them one by one and look through the difficult questions. And I hope you all ace Paper One. InshahAllah :)

Starting with May-June 2002:
1. The answer is A as the particle has zero mass and a negative charge hence,fulfilling the properties of an electron.
2. The answer is D for firstly we calculate the percentage by mass of Carbon in 1.80 kg using the Empirical Formula and then calculate its moles by dividing by twelve and then multiply by 44 which the Mr. of Carbondioxide to get the mass.
3. The relative atomic mass is calculated as follows: (63x7)+(65x3)/10 which is equal to 63.6.
4. It is always the difference in electro negativities which is a reason for polarity.
5. The delocalised electrons in a metal are referred to as bonding electrons for they are responsible for electrostatic forces of attraction between the positive cation and themselves.
6. We calculate this through P1V1+P2V2=P3V3 > which is (1x2)+(2x1)= 3x P > Hence P= 4/3 k Pa that is A.
7. Since there are weak bonds hence the bonds are said to be molecular.
8. The standard enthalpy change of combustion is when one mole of carbon is completely burnt to form carbon dioxide which is the same as the enthalpy change of formation.
9. Add all the bond energies: (390x4)+160 = 1720
10. It will be in case B, we cant take a for Kc for solids cannot be calculated.
 
Z

Zizu1992

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11. In the diagrams given the reaction rate is being measured with respect to products hence in C the products are being consumed after being formed hence referring to an auto catalytic reaction.
12. The anion of Phosphorus is going to have the largest radius ( Refer to ionic radii graphs)
13. MgO wont react with Sodium Hydroxide because of two reasons, one it is weakly basic and two it is sparingly soluble.
14. Only the chlorides of Magnesium and Sodium dissolve in water to give neutral solutions. Since only sodium is an option we choose A.
15. The answer is D since all Group II elements form an oxide with Nitrogen Dioxide and Oxygen.
16. Keep in mind the equation of the reaction i.e 2NaCl + 2H2O > 2NaOH + H2 + Cl2
17. The ion acts as a conjugate acid.
18. It is a reducing agent hence, it prevents oxidation of food.
19. Free radical substitution since a Hydrogen atom was replaced by a Halogen.
20. The answer is D. (It too simple :p)
 
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Octahedral

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Textiles for use in aircraft are treated with a finish containing a halogenoalkane.What is the reason for this? One of the reasons given in the options is:
The fabric forms hydrogen bonds to water more readily, making the fabric easier to wash.What does this mean?Is this actually true?I think it is but the marking scheme says otherwise.Could someone explain this please?
 
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Zizu1992

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21. You have to draw all the isomers of the chloroethane in this question which turn out to be 9.
22. The bond in pvc is going to be a single bond hence longer and weaker.
23. Since the product acid has an extra carbon hence reaction with CN is inevitable and then we get the resultant acid.
24. CO is formed when oxygen is not in excess.
25. The answer is A since it forms a chiral centre on reaction unlike the other compounds by breaking its oxygen double bond.
26. Ethanol decolourises potassium manganate because it can be oxidised to an acid and it does not decolourise bromine due to absence of double bond.
27. Only esters fulfill the criteria as they are oily liquids, immiscible with water and cannot be further oxidised.
28. The compound should have a carbonyl group to show positive test and OH group to react with PCl5.
29. D as the acid group will cause effervescence due to production of CO2.
30. Use the answers to form the resulting ester.
 
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