Predict which halogen reacts most violently with hydrogen.
Hydrogen reacts with chlorine in an exothermic reaction. $\text{H}_2(g) + \text{Cl}_2(g) \rightarrow 2\text{HCl}(g)$, $\Delta H = -185\,\text{kJ mol}^{-1}$. Explain, in terms of bond breaking and bond forming, why this reaction is exothermic.
Each mole of chlorine molecules that reacts releases 185 kJ of energy. Calculate the amount of energy released when 106.5 g of chlorine reacts.
Hydrogen reacts with iodine in a reversible reaction. $\text{H}_2(g) + \text{I}_2(g) \rightleftharpoons 2\text{HI}(g)$, $\Delta H = +53\,\text{kJ mol}^{-1}$. The reaction is studied at a temperature of $400\,^{\circ}\text{C}$. Describe and explain what happens to the position of equilibrium if the pressure is increased.
The reaction is studied at 25 atmospheres pressure. Describe and explain what happens to the position of equilibrium if the temperature is decreased.
Hydrogen iodide dissolves in water to form hydroiodic acid, HI(aq). Hydroiodic acid is a strong acid. Write an equation to show the dissociation of hydroiodic acid.
Calcium reacts with hydroiodic acid. Write the equation for this reaction.
Hydroiodic acid reacts with sodium carbonate. Write the ionic equation for this reaction.