Part 1,
For Catholics, when God "establishes his eternal plan of ‘predestination,’ he includes in it each person’s free response to his grace" (CCC 600). Thus, anyone who is finally saved will have been predestined by God because it was God’s predestined plan and God’s grace that went before him and enabled him to be saved.
However, this does not mean that God has predestined anyone for hell. Indeed, the Bible cannot be any plainer than to say God is, "not wishing that any should perish, but that all should reach repentance" (2 Pt 3:9). God wills all to be saved. To be damned, a person must willfully reject God’s "predestined plan" for his salvation, simple enough.
The above comes from the teachings of the Catholic Church and so is much of the following
But for a Calvinist, Ephesians 2:1 declares all who are apart from Christ to be "dead in trespasses and sins." In that view, to say a man could freely choose to accept or reject God’s grace and invitation to salvation would be as ridiculous as saying a corpse could choose to raise itself from the dead. Moreover, for Jesus’ declaration that a man must be "born anew" in John 3:3 to include the freedom to reject the offer would be akin to saying a baby has a say in whether or not he will choose to be born.
Romans 9:18-22 is perhaps the favorite-among-favorites of Calvinists:
So then he has mercy upon whomever he wills, and he hardens the heart of whomever he wills. You will say to me then, "Why does he still find fault? For who can resist his will?" But who are you, a man, to answer back to God? Will what is molded say to its molder, "Why have you made me thus?" Has the potter no right over the clay, to make out of the same lump one vessel for beauty and another for menial use? What if God, desiring to show his wrath and to make known his power, has endured with much patience the vessels of wrath made for destruction . . .
Could Paul be clearer? Our salvation is entirely dependent on God’s unchangeable will. The free will of which the Catholic Church speaks is simply unbiblical. Shall we all join the local Calvinist ecclesial community, then? The answer seems—predestined.
Part 2 to follow-