How heavy is an object that displaces 400n of water in a pool?

All we can say is that the object's volume is about 41 liters. That's the same as the volume of water displaced.

We can't say anything about the object's weight. There is no direct connection between the weight of the object and the weight of the water it displaces.

Texture and composition are different because they are not the same aspect. texture has to do with feel and so on, where as composition is the chemical makeup which you cant touch like you can texture.