Quick questions on Enthalpy, entropy and free energy - WJEC A-Level Chemistry

When an ionic solid dissolves, two enthalpy terms compete: the lattice must be broken apart (the reverse of the exothermic lattice enthalpy, so endothermic) and the gaseous ions are then hydrated (exothermic enthalpy of hydration). The enthalpy of solution is the sum of these, $\Delta H_{sol} = -\Delta H_{latt} + \Sigma \Delta H_{hyd}$. If hydration releases more energy than is needed to break the lattice, dissolving is exothermic; if not, it is endothermic and may only occur because of a favourable entropy increase as ordered solid disperses into solution.

State the sign of lattice enthalpy and explain why. [1 mark]

State the condition on $\Delta G$ for a reaction to be feasible. [1 mark]

Predict the sign of $\Delta S$ for $\text{CaCO}_3(s) \rightarrow \text{CaO}(s) + \text{CO}_2(g)$. [1 mark]

State the two enthalpy terms that combine to give the enthalpy of solution. [1 mark]

Explain why a reaction with $\Delta G < 0$ may still not occur at room temperature. [1 mark]