What substance has a mass of 9.5g and volume of 2.1cm^3

An atom of which element reacts with an atom of hydrogen to form a bond with the greatest degree of polarity ?

How many liters of ethylene glycol antifreeze (c2h6o2), with a density of 1.100 g/l, would you add to your car radiator containing 15.0 kg of water if you needed to protect your engine to - 21.5°c? for water, kf = 1.86°c m -1.

Who discovered a pattern to the elements in 1869?