With how many significant figures we should report the volume of a sphere of 1.3 cm radius?

The boiling point of liquids is very high what does it indicate

How many mmols of tris-hcl are there in 100 ml of a 100 mm tris-hcl buffer solution at ph 8.1? note that the 100 mm refers to the sum of tris and tris-hcl concentrations?

What must be in balance for temperatures to remain constant?