Is mass intrinsic property of a material?
Mass is an intrinsic property of any any physical object. Intrinsic property refers to the thing than an object has within it which is influenced by other things.
Does the universe have a center? Explain.
Yes, the centre of the universe was given by two famous theories; geocentric theory (Earth as a centre of the universe) and Helio-centric theory (Sun as a centre of the universe). So, we can consider our galaxy as the centre of the universe. This is because the universe looks more or less the same from all locations.