The energy diagram shown represents the chemical reaction between solid ammonium chloride and solid barium hydroxide octahydrate: 2NH4Cl(s)+Ba(OH)2⋅8H2O(s)→2NH3(aq)+BaCl2(aq)+10H2O(l) The ΔH for this reaction is 54.8kJ . How much energy would be absorbed if 24.1g of NH4Cl reacts?

Question

aaronq · Answer

$\sf \Delta H_{rxn}=54.8~kJ/mol$

find moles, n.   $n=\dfrac{mass}{Molar~mass}$

Divide moles by the stoichiometric coefficient (which is 2) and multiply by $\sf \Delta H_{rxn}$

anonymous · Answer

I don't get it :/

aaronq · Answer

do you know how to find the molar mass of $NH_4Cl$?

anonymous · Answer

53.5 is what I got

aaronq · Answer

that's the mass, the molar mass is the mass of one mole of $NH_4Cl$ molecules.

you add up the individual molar masses of each atom present

N+4*H+Cl= 14 g/mol + 4*(1 g/mol)+ 13 g/mol= 53.5 g/mol


then divide the mass by that number then divide by 2

multiply by $\Delta H$

aaronq · Answer

sorry the molar mass of chlorine is 35, not 13. but that result is right, i just wrote it wrong

anonymous · Answer

So 12.3 kJ correct?

aaronq · Answer

yup thats right