Question

What is the energy change if 210 g of NaHCO3 decomposes in the following reaction?

2NaHCO3 (s) yields Na2CO3 (s) + H2O (l) +CO2 (g) delta H = 85 kJ

Answers -

53 kJ of energy is released by the reaction.

106 kJ of energy is absorbed by the reaction.

159 kJ of energy is released by the reaction.

212 kJ of energy is absorbed by the reaction.

Answer 1

106 kJ of energy is absorbed by the reaction.

Step-by-step explanation:

From the reaction, when two moles of NaHCO3 are decomposed an energy of 85 kJ are absorbed.

But, molar mass of NaHCO3 is 84 g/mol

Therefore;

2 × 84 g = 168 g absorbed 85 kJ

Thus; a mass of 210 g of NaHCO3 will absorb an energy of;

= (210/168) × 85

= 106.25 kJ

= 106 kJ of energy is absorbed in the reaction.