The enthalpies of formation of the compounds in the combustion of methane, Upper C upper H subscript 4 (g) plus 2 upper O subscript 2 (g) right arrow upper C upper o subscript 2 (g) plus 2 upper H subscript 2 upper O (g).,

are CH4 (g): Delta. Hf = –74.6 kJ/mol; CO2 (g): Delta. Hf = –393.5 kJ/mol; and H2 O(g): Delta. Hf = –241.82 kJ/mol.

How much heat is released by the combustion of 2 mol of methane?
Use Delta H r x n equals the sum of delta H f of all the products minus the sum of delta H f of all the reactants..

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).

the answer is symmetrical : )