using sudo on GUI applications

When I was using kubuntu, I could always open X applications with sudo, sudo kate for example. Now that I’ve switched to arch that doesn’t work. I know I’ve always been told to use kdesu, but what setting is there in kubuntu that lets me use sudo on X apps that prevents me from doing it on arch?

Number of lines outputted by ls

When ls is called, it outputs all the files/directories in the current directory, attempting to fit as many as possible on each line. Why is it that when passed to wc -l, it outputs the number of files? How does it decide how many lines to output its results in?