The mass is 5kg
I hope this helps
No more solute will dissolve at that temperature, the temperature would have to be increased in order for more solute to dissolve.
The asthenosphere is directly below the lithosphere so the answer to your question is the asthenosphere, because the outer core is towards the center of Earth.
A mineral occurs naturally, meaning that even though there are artificial substances that might be described as mineral-like they are not minerals