What carpet Burns in a deficiency of O2 a mixture of CO and CO2 forms. Carbon Burns in excess O2 to form only CO2 and CO Burns in excess O2 to form only CO2. Calculate ΔH for C(graphite +1/2O2) →CO(g).

Explanation:

From the combustion of carbon, the reactions occurring in limited oxygen conditions are:

If it occurs in excess, then any leftover CO changes to CO2. i.e.

  ---- (1)

         ----- (2)

From (1), the enthalpy change is:

From (2), the enthalpy change is:

Subtracting (2) from (1), we get:

The enthalpy change ΔH of the reaction = -110.5 kJ/mol

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.