A validly ordained priest offering unleavened wheat bread and unadultered grape wine using approved prayers would be offering a valid Mass.
The celebrant of mass must be an ordained Catholic priest. This includes monsignors, bishops, archbishops and popes.
A Catholic must be present for the following in a single Mass: Offertory Consecration Communion
Before a Catholic marries a non-Catholic, the Catholic must (for the marriage to be considered proper by the Catholic Church) agree to raise any children as Catholics.
A Catholic is bound to attend Sunday Mass and Holy Days of Obligation under pain of mortal sin. The bare minimum, if we speak according to the law and not the spirit, that a Catholic must be present for in regard to the Mass is from the time of the Offertory to the Communion of the priest. If one arrives too late or leaves too early in respect this portion of the Mass, one has not fulfilled their Sunday obligation and must attend another Mass that day.
To be considered Catholic by the Church, you must be baptized in the Catholic Church, or else properly baptized in another church and formally received into the Catholic Church by a priest. Being born to Catholic parents isn't enough. You can be the Pope's nephew, but if you haven't been baptized, you are not Catholic.
To participate in the Eucharist, you must be a confirmed Catholic who is in a state of grace (i.e., who has not committed a mortal sin since the last confession). If you are not Catholic, it is permissible to attend mass, but not partake of the Eucharist.
The mass of reactants must be equal to the mass of products.
To be a saint the person must be a Christian and to be a catholic saint the person would need to be a catholic Christian. However not all catholics are saints.
The requirements to be considered for the position of pope - one must be a male Catholic. That pretty much eliminates a Jew from consideration. The only way it could happen would be if the person was an ethnic Jew who had converted to Catholicism. Saint Peter was a Jew before he became a Catholic. Does that count?
The force of gravity must be greater than the mass of the object
Yes. While the catholic church recognizes the Baptism as valid it does not recognize the Confirmation as valid, since it requires administration by a priest having received the valid sacrament of holy orders. While the Catholic Church and Episcopal Church are close in tradition and both have seven sacraments, only Baptism is considered as valid.
.Catholic AnswerI would be tempted to say 100% if only for the reason that to be a Catholic is to faithfully observe the laws of the Church and to be a Catholic means that you must attend Mass every Sunday and holy day. However there are a lot of people who say that they are "Catholic" even if they don't attend Mass each week, I am assuming that is what you are referring to. A little over 75% of the people who CLAIM to be Catholic do not attend weekly Mass.