Asample of pure solid naphthalene (c10h8) weighing 0.6410 g is burned completely with oxygen to co2(g) and in a constant-volume calorimeter at 25°c. the amount of heat evolved is observed to be 25.79 kj.
write and balance the chemical equation for the combustion reaction.

C10H8 + 12O2 > 10CO2 + 4H2O

Explanation:

To balance this, we have to make sure that the same number of atoms exist at both sides (Conservation of energy)

Note:The reaction is exothermic, giving off heat energy.

Left hand side: C= 10,

H=8,

O= 2×12=24

Right hand side: C= 10×1=10,

H= 4×2=8,

O=10×2=20 (for 10CO2) and 4×1=4 (All equal to 24)

With the above analysis, it is clear that numbers had to be added to molecules to get an equal number of atoms for both sides.

in theory, limestone is composed principally of the compound calcium carbonate - caco3, but in reality this compound is deposited in conditions involving a number of other compounds as impurities so it ends up being a mixture of many compounds.

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tony (lordcaos066)

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