Consider the decomposition of water, 2H2O —> 2H2 + O2. Is energy released or absorbed in this reaction? Discuss bond energy in your answer.

When atoms bond together to form compounds, they attain lower energies. The difference between energies of the bonded atoms and individual atoms is released in this case.

Similarly, when the compounds, like water, are broken, energy is absorbed, and the resultant atoms have higher energy.

2H₂O  ⇒  2H₂ + O₂

The energy required to break this bond is known as bond energy.

For example in the given reaction, 469kJ/mol is the bond energy absorbed to carry out the reaction.

the grams   of   barium that   are in   2.3 x 10^23   atoms of barium   is   52.4 g (answer c)

    calculation

mass = moles   of ba   x molar   mass of ba

  molar mass of ba from periodic table=   137.3 g/mol

  use the   avogadro's law   constant   to   calculate the moles of barium

  that   is     1 mole =   6.02   x 10^23 atoms

                    ? moles = 2.3 x 10^23   atoms

by cross   multiplication

=(1 mole   x 2.3x 10^23 atoms)   / 6.02   x10^23 atoms)=   0.382   moles

mass   is therefore = 137.3   g/mol x 0.382 mol = 52.4 ( answer c)

explanation:

the electrical  conductivity  of asolution  of an electrolyte is measured by determining the resistance of thesolution  between two flat or cylindrical electrodes separated by a fixed distance.