Question

According to the following thermochemical reaction, how much energy is involved in the reaction of 18.5 g of NaHCO3? Is the reaction endothermic or exothermic according to how the thermochemical equation is written?

2NaHCO3(s) + 129 kJ → Na2CO3(s) + H2O(l) + CO2(g)

Answer 1

You have to add heat so endothermic

129 J per 2 mol

1 mol = 23 + 1 + 12 + 48 = 84 grams
2 mol = 168 grams
we only have 18.5 grams so
(18.5/168)129 = 14.2 Joules

Answer 2

I think Damon made a typo. That is kJ and not J.

Answer 3

Thanks for catching that !!!