Calculate the standard enthalpy change for the reaction 2A+B⇌2C+2D Use the following data: Substance ΔH∘f (kJ/mol) A -235 B -413 C 193 D -493

ΔH = 283kJ/mol

Explanation:

Using Hess's law, the ΔH of a reaction is equal to the sum of ΔH° of products times its coefficient subtracting the sum of ΔH° of reactants times its coefficient. Replacing, for the reaction:

ΔH = 2ΔH°C + 2ΔH°D - (2ΔH°A+ΔH°B)

ΔH = 2*193kJ/mol + 2*-493kJ/mol - (2*-235kJ/mol+ (-413kJ/mol)

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).

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