To solve the problem, we can use the formula:
q = m × c × ΔT
where q is the heat energy released, m is the mass of the iron, c is the specific heat of iron, and ΔT is the change in temperature.
Substituting the given values and solving for m, we get:
q = m × c × ΔT
188.90 J = m × 0.450 J/g°C × (75.66°C - 35.47°C)
188.90 J = m × 0.450 J/g°C × 40.19°C
m = 188.90 J / (0.450 J/g°C × 40.19°C)
m = 9.96 g
Therefore, the mass of the piece of iron is 9.96 g.