Pepperell Stretch Magic 0.5mm Bead and Jewelry Cord, 100m, Clear

Is this easy to tie knots in? Or how do you finish your jewelry using plastic cord?

Would this work for necklaces? My daughter (10) creates jewelry using the glass or stone beads you'd find at Michael's.

What is the cord made of?

Will a double knot of this size fit inside a 4mm bead?