The enthalpy change : -196.2 kJ/mol
<h3>Further explanation </h3>
The change in enthalpy in the formation of 1 mole of the elements is called enthalpy of formation
The enthalpy of formation measured in standard conditions (25 ° C, 1 atm) is called the standard enthalpy of formation (ΔHf °)
(ΔH) can be positive (endothermic = requires heat) or negative (exothermic = releasing heat)
The value of ° H ° can be calculated from the change in enthalpy of standard formation:
∆H ° rxn = ∑n ∆Hf ° (product) - ∑n ∆Hf ° (reactants)
Reaction
2 H₂O₂(l)-→ 2 H₂O(l) + O₂(g)
∆H ° rxn = 2. ∆Hf ° H₂O - 2. ∆Hf °H₂O₂

Answer: Between 1 and 2.
Explanation:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
............(1)
where,
a = amount of reactant left after n-half lives = 40
= Initial amount of the reactant = 100
n = number of half lives
Putting in the values we get:

taking log on both sides


Thus half-lives that have elapsed is between 1 and 2
Answer:
1. Hydrogen
Explanation:
These planets contain liquid hydrogen in their interior, while the earth has liquid iron in it.
When liquid hydrogen is in tremendous pressure enviroments, the electrons that make up each atom of this element end up "jumping" to other atoms. These "jumps" allow liquid hydrogen to behave like a metal.
In addition, with the constant energy released by the nucleus of planets like Jupiter and Saturn, as well as their rotations, the liquid hydrogen receives induction of currents, giving rise to extremely powerful magnetic fields.