The system of units which at present Internationally accepted for measurement is the SI units.What is the full form of SI?

The system of units which at present Internationally accepted for measurement is the SI units.The initial and final temperature of water in a container are observed as 15 ± 0.5 ^@C and 40 ± 0.2 ^@C . What is the rise in the temperature?

What is the Si unit of pressure?

Define surface energy. What is its SI unit?

What is the SI unit of mass? How is it defined?

A crystalline solid has simple cubic structure in which P atoms are present at the corners, Q atoms are present at the edge centres and R atoms are present at the centre of the unit cell. What is the formula of the compound?