How much mL of 0.5m HCL would it take to compeletly react with 3.00g CaCO3?

CaCO3 + 2HCl --> CaCl2 + H2O + CO2

mols CaCO3 = grams/molar mass = ?
mols HCl = 2 x mols CaCO3 from the coefficient in the balanced equation.
M HCl = mols HCl/L HCl. You know M HCl and mols HCl, solve for L HCl and convert to mL.