If more HCl is added to the system, how will the reactions

The reaction below occurs in a closed system. The reactants were mixed and the reaction was allowed to reach equilibrium.

Is this reaction a single replacement or a double replacement? Explain your answer.
If more HCl is added to the system, how will the reactions shift to reach equilibrium again?
If CO2 is removed from the system, how will the reactions shift to reach equilibrium again?
If heat is added to the system, how will the reactions shift to reach equilibrium again?
What is the principle that helps identifies shifts in equilibrium?

CaCO3 (s) + 2HCl (g) CaCl2 (s) + H2O (l) + CO2 (g) ∆H = –90 kJ/mol
Answer: