Question

when 0.628 g of sodium metal is added to an excess of hydrochloric acid, 6530 J of heat are produced. What is the enthalpy of the reaction written?

2 Na(s) + 2HCl (aq) = 2 NaCl (aq) + H2 (g)

Answer 1

Answer:

Here, we are assuming the heat to be produced per mole of Na and HCl reaction.

Hence, given reaction can be further simplified to the below reaction;

Na(s) + HCl(aq) --> NaCl(aq) + 1/2 H₂ + Δ

Here the moles of Na present = 0.628/22.99 = 0.0273 mol

and thus the ΔH_rxn will be

ΔH_rxn = 6530J/0.0273 mol = 239.19 kJ.mol^-1

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