The balanced chemical equation for the reaction between Na2CO3 (sodium carbonate) and CaCl2 (calcium chloride) is:
Na2CO3 (sodium carbonate) + CaCl2 (calcium chloride) -> 2NaCl (sodium chloride) + CaCO3 (calcium carbonate)
Given that you have 0.5 moles of Na2CO3, you need 0.5 moles of CaCl2 for the reaction to go to completion.
The number of moles of NaCl produced in the reaction can be calculated by multiplying the number of moles of Na2CO3 by the coefficient in front of NaCl in the balanced equation:
2NaCl/1Na2CO3 * 0.5 moles Na2CO3 = 1 mole NaCl
Therefore, the reaction between 0.5 moles of Na2CO3 and enough CaCl2 to react completely would produce 1 mole of NaCl.