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    Help please! I have no idea how to do this. The answer is 2.6 MJ - How??

    10Al(s) + 6NH4ClO4(s) 4Al2O3(s) + 2AlCl3(s) + 12H2O(l) + 3N2(g)
    Enthalpy change = -9769 kJ mol-1
    Given that 450 tonnes of solid propellant are used in the solid rocket boosters in total, and that aluminium is the limiting reagent present at 16% in the mixture, calculate the energy released when this is reacted according to the above equation.

    When you say
    Enthalpy change = -9769 kJ mol-1
    That is very ambiguous. The unit is kJ per mole, but per mole of what? Of Aluminium? Of AP?
    Similarily, when you say
    present at 16% in the mixture
    Does that mean 16% in terms of mass? In terms of quantity? In terms of volume?

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