The claim

“are their really 7 aces in a deck of 52 cards?”

No— a standard 52-card deck has 4 aces (one per suit), not 7.

A standard deck used in most card games contains 52 cards divided into 4 suits (clubs, diamonds, hearts, spades). Each suit has 13 ranks (Ace, 2–10, Jack, Queen, King), so there is exactly one Ace per suit, totaling 4 aces. You might see more than 4 aces only if using multiple decks combined, adding jokers/extra cards, or a non-standard specialty deck. In ordinary usage, the claim of 7 aces in a 52-card deck is incorrect.