Complete the reaction pathway diagram in Fig. 2.1 for reaction 2. Add labels to indicate the enthalpy change, $\Delta H_2$, and the activation energy, $E_A$.
Describe one further observation that indicates the reaction is complete.
Calculate the value of $\Delta H_1$ in $\text{kJ mol}^{-1}$. Assume that the reaction mixture has the same specific heat capacity as water and that no heat is lost to the surroundings. Show your working.
When $\text{NaHCO}_3$ is heated, thermal decomposition takes place. reaction 3: $2\text{NaHCO}_3 \rightarrow \text{Na}_2\text{CO}_3 + \text{H}_2\text{O} + \text{CO}_2$ Calculate the enthalpy change for reaction 3, $\Delta H_r$, using the data in Table 2.1 and the value of $\Delta H_1$ obtained in (b)(ii). (If you could not calculate a value for $\Delta H_1$ in (b)(ii), assume the enthalpy change is $-38.4\ \text{kJ mol}^{-1}$. This is not the correct value.)
Z is a salt containing a Period 4 element from Group 2. On heating Z, a brown gas is produced. Identify the formula of Z and then use it to write an equation for the reaction.