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)

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

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.