Grace
Bible: God's disposition toward mankind, wherein He expresses His mercy and love, so that the believer is now treated as if he were innocent and righteous.
Catholicism: A power - separate from God - which is placed into a believer. This power enables the believer to perform works that will earn him or her the "right" to heaven.
Salvation
Bible: The instantaneous reception of an irrevocable right-standing before God. Salvation is secured by faith, through the grace of God. It is not given only to those who have lived in a worthy way. Romans 3:23 tells us that "all have sinned and fall short of the glory of God." No, salvation is given to those the Bible describes as "ungodly," "sinners," "enemies," and "children of wrath."
Catholicism: The lifelong process whereby God and men cooperate in the securing of forgiveness of sin. This is achieved only after death (and/or cleansing from sin in purgatory), and is dependant on man's personal securing of objective righteousness before God; otherwise, there would be no salvation.
Reconciliation (atonement for sins)
Bible: All sins are forgiven at the point of salvation, because Christ's death satisfied all God's wrath against sin. (See Colossians 2:13,14)
Catholicism: Sins are only potentially forgiven, and so must be worked off through a process mediated by the Church and its sacraments over the lifetime of the believer.
Regeneration
Bible: The instantaneous imparting of eternal life and the quickening of the human spirit, making it alive to God.
Catholicism: The lifelong process of infusing grace (spiritual power) to perform meritorious works (in part).
Justification
Bible: The legal declaration of Christ's righteousness reckoned to the believer at the point of faith, solely as an act of God's mercy.
Catholicism: Spiritual rebirth and the lifelong process of sanctification which begins at the point of the sacrament of baptism.

