The jovian planets contain large abundances of hydrogen and helium because

The larger elements are stratified at the core of the Jovian planet. The gravitational force is so large that part of the core consists of liquid hydrogen. That which cannot be captured by the core is in the upper regions in gaseous form. 

Helium is one of the noble gases (the lightest one) and has an extremely low melting point. It addition it will combine with absolutely nothing that I know of. So helium has found itself in the upper regions of the planet as well.

The answer is S = 0.1528 cal/g °C

Explanation:

By the law of conservation of energy, energy is neither created nor destroyed.

So, energy lost by metal pieces is equal to the energy gained by water in the calorimeter.

Specific heat of water is 1 cal/g °C

⇒ heat energy  Q = mSΔT, where m = mass of a substance

                                                        S = specific heat

                                                        ΔT = change in temperature

Now, the heat lost by metal piece, Q = 72×S×(96-31)

                                                      = 4680×S cal

Heat gained by water, Q = 130×1×(31-25.5)

                                        = 715 cal

⇒ 4680×S = 715.

⇒ S = 0.1528 cal/g °C.