What is the enthalpy of the reaction as written?

Question

When 0.636 g of sodium metal is added to an excess of hydrochloric acid, 6610 J of heat are produced. What is the enthalpy of the reaction as written?

2Na(s)+2HCl(aq)⟶2NaCl(aq)+H2(g)

Enthalpy of reaction: ?kJ

Answer 1

When 0.636 g of sodium metal is added to an excess of hydrochloric acid, 6610 J of heat are produced. What is the enthalpy of the reaction as written?

2 Na_(s) + 2 HCl_(aq) → 2 NaCl_(aq) + H_2(g)

SOLUTION

GIVEN DATA

Mol Na_(s) = 0.636 g / 23.0 g/mol = 0.028 mol

0.636 g Na_(s) or 0.028 mol produces 6610 J heat, then 2 mol Na_(s) produces the heat as



2 mol Na_(s) = 6610 J /0.028 mol x 2 mol Na_(s) = 472142.9 J = 472.1429 KJ