Answer to Question #2684 in Physical Chemistry for Noreena
Mg(s) + CuSO4(aq) --> MgSO4(aq) + Cu(s)
Find the energy change by using ΔH = - mcΔT
(MY ANSWER) 100 x 4.2 x 45 = 18900 J mol-1 = 18.9 kJ mol-1 (which is correct)
Find how many moles reacted (n)
(MY ANSWER) 1.6/159.6 = 0.01 then 0.01/2 = 0.005 (which is incorrect, correctly should be 2x100/1000; do not know how!)
Scale the quantities for the combustion of 1 mole (ΔH/n)
18.9/0.005 = -3780 kJ mol-1 (using the previous incorrect figure this is also wrong)
Could you please help to explain step 2?
n(CuSO4) = (2 mol/dm3)*100cm3/1000 = 0.005 mol
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