Answer
Heat transfer : -0.841kJ or -841J.
Work Step by Step
Molar Mass ($I_2$):
126.9* 2 = 253.8g/mol
1. Calculate the amount in moles:
$3.42g \times \frac{1 mol (I_2)}{ 253.8} = 0.0135 mol$
2. Divide the amount by the coefficient of $I_2$:
$\frac{0.0135}{ 1} = 0.0135 mol - reaction$
3. Find the necessary heat:
** Since we are talking about the reverse reaction, the $\Delta_rH^{\circ}$ is negative.
$0.0135mol-reaction \times (-62.4) kJ/mol-reaction = (-0.841)kJ$
