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ruby92:
m/j 2010 paper 42
Q2 b and c

Master_Key:
Q2 B (i)  For Mg(OH)2 = 2993 - (1890 + (2*550)) = 3 kJ mol-1

            For Sr(OH)2 = 2467 - (1414 + (2*550)) = -47 kJ mol-1

(ii)  Sr(OH)2 is more soluble in water as it releases energy when it dissolves in water (Exothermic).

(iii) Sr(OH)2 is less soluble in hot water as it releases energy when it dissolves in water (Exothermic). The same principle as in equilibrium.

elemis:
http://www.xtremepapers.net/CIE/International%20A%20And%20AS%20Level/9701%20-%20Chemistry/9701_s02_qp_1.pdf

Question 6, 9 and 16, please.

Deadly_king:

--- Quote from: Kirin on December 02, 2010, 10:54:42 am ---http://www.xtremepapers.net/CIE/International%20A%20And%20AS%20Level/9701%20-%20Chemistry/9701_s02_qp_1.pdf

Question 6, 9 and 16, please.

--- End quote ---

Jun 02 p1

6. Make use of the formula PV = nRT

It is said in the question that temperature is constant and so is the number of moles. In other words P is inversely proportional to V.

Therefore P1V1 = P2V2

P1V1 is given by the sum of the initial PxVx + PyVy while the final volume V2 will be Vx + Vy.

So (2 x 1) + ( 1 x 2) = P2(1 + 2) ----> P2 = 4/3

Answer is A.

9. Enthalpy change of atomisation is the energy required to convert one mole of hydrazine to its respective atoms.

In other words we just have to break all the bonds involved within its structure.

Energy required to break 1 N-N bond + 4 N-H bond. Use values from the data booklet to find the required answer. ;)

Delta H = 160 + 4(390) = 1720 KJ

Answer is B.

16. You need to know this equation by heart. ;)

NaCl + 2H2O -----> Cl2 + H2 + 2NaOH

Answer is B.

elemis:
http://www.xtremepapers.net/CIE/index.php?dir=International%20A%20And%20AS%20Level/9701%20-%20Chemistry/&file=9701_w02_qp_1.pdf

I dont understand how the answer is D for Question 11.

Please help me.

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