The probability of choosing a heart, P(Heart) = 13/52 = 0.25.
Without replacement, you now have 51 cards left in the deck.
So the probability of subsequently choosing a Spade is, P(Spade) = 13/51.
The probability of choosing a heart AND then a space, without replacement is:
(13/52) * (13/51) = .06372549
(Remember, "AND" statements envoke the multiplication rule; "OR" statements envoke the additional rule. And when you sample WITH replacement, you have to then account for the missing cards in subsequent draws.)