Use the standard enthalpies of formation for the reactants and products to solve for the δhrxn for the following reaction ca(s)+ 2h20(l) → ca(oh)2(s)+h2(g) ∆hrxn= the reaction is =

- 386.6 kJ/mol.

Explanation:

To solve this problem, we can use Hess's Law:  

ΔHrxn = ΣΔHf(products) - ΣΔHf(reactants)

For this reaction: Ca(s)+ 2H₂O(l) → Ca(OH)₂(s) + H₂(g),

∴ ΔHrxn = ΣΔHf(products) - ΣΔHf(reactants) = [ΔHf(Ca(OH)₂(s)) + ΔHf(H₂)(g)] - [ΔHf(Ca)(s) + 2*ΔHf(H₂O)(l)].

knowing that:

ΔHf(Ca(OH)₂(s)) = - 985.2 kJ/mol, ΔHf(H₂)(g) = 0.0 kJ/mol, ΔHf(Ca)(s) = 0.0 kJ/mol, ΔHf(H₂O)(l) = - 285.8 kJ/mol.

∴ ΔHrxn = ΣΔHf(products) - ΣΔHf(reactants) = [ΔHf(Ca(OH)₂(s)) + ΔHf(H₂)(g)] - [ΔHf(Ca)(s) + 2*ΔHf(H₂O)(l)] = [(- 985.2 kJ/mol) + (0.0 kJ/mol)] - [(0.0 kJ/mol) + 2*(- 285.8 kJ/mol)] = - 386.6 kJ/mol.

The angle of reflection is 30°

The nucleus inside an atom consists of positively-charged  protons  and neutrally-charged  neutrons. a  proton  is a subatomic particle with a positive electric charge. allprotons  are identical.