Answer to Question #349284 in General Chemistry for zaza

Question

Give an example of

a) an endothermic process that is spontaneous

b) an exothermic process that is spontaneous

c) a reversible process

d) an irreversible process

Answer 1

Solution:

a) an endothermic process that is spontaneous

The reaction of baking soda (NaHCO₃) with vinegar (CH₃COOH) is endothermic

NaHCO₃(s) + CH₃COOH(aq) → CH₃COONa(aq) + H₂O(l) + CO₂(g), ΔH°_rxn = +2945.2 kJ

b) an exothermic process that is spontaneous

The oxidation of sulfur dioxide (SO₂) by oxygen gas (O₂) to sulfur trioxide (SO₃) is an exothermic reaction

2SO₂(g) + O₂(g) → 2SO₃(g), ΔH°_rxn = −198.2 kJ

c) a reversible process

The reaction of hydrogen gas (H₂) with iodine gas (I₂) gives hydrogen iodide (HI) – a reversible reaction

H₂(g) + I₂(g)  ⇆ 2HI(g)

d) an irreversible process

The reaction of sodium (Na) with water (H₂O) is an irreversible process

2Na(s) + H₂O(l) → 2NaOH(aq) + H₂(g)