In addition to @Rumtscho's answer: chicken breast is often injected with water to increase profit, especially when you buy it in discount stores.
When you heat it, that water turns to steam, and if it leaks first into the hot oil or butter you get serious splatter.
It's bad enough some people call it "exploding chicken", and radical vegan organisations use it as an instrument to try to force laws against eating chicken, and especially against selling meat at a discount.
Frying time would of course depend heavily on the thickness of the chicken breasts as well as the heat you're using. And whether you spread them open before frying, if you don't they're twice as thick and will take a lot longer (and can easily be blackened on the outside while still raw on the inside).
Personally, I've had good results putting chicken breasts in the oven. Spice as desired, then fry lightly to get a nice crisp crust on them, cook in the oven at 175C for about half an hour to get them well done and still nicely moist.
No splatter that way either.