Question

When 0.230 g of sodium metal is added to an excess of hydrochloric acid, 2390 J of heat are produced. What is the enthalpy of the reaction as written?
2Na(s)+2HCl(aq)⟶2NaCl(aq)+H2(g)

Answer 1

Answer:

ΔHrxn = 239 kj/mol

Explanation:

Given data:

Mass of sodium = 0.230 g

Heat produced = 2390 J

Solution:

Chemical equation:

2Na + 2HCl → 2NaCl + H₂

Number of moles of sodium:

Number of moles of sodium = mass / molar mass

Number of moles of sodium = 0.230 g / 23 g/mol

Number of moles of sodium = 0.01 mol

Enthalpy of reaction:

ΔHrxn =  2390 J / 0.01 mol

ΔHrxn = 239000 j/mol

ΔHrxn = 239 kj/mol