Water and methane have similar molar masses. methane changes from liquid to a gas. what could account for the difference

1 answer:

5 0

Water contains more electronegative oxygen. Hydrogens bonded directly to oxygen atoms gets partial positive charge which means the electron density on hydrogen atoms has decreased and a partial negative charge forms on oxygen atom. This partial negative charge on oxygen and partial positive charge on hydrogen attracts each other and forms intermolecular force called Hydrogen Bonding.

H₂O ------ H₂O ------- H₂O

The dashed line show hydrogen bonding.

In case methane hydrogen atoms are bonded to Carbon atoms and there is very small electronegativity difference between them, hence, fails to form partial positive and partial negative charge, hence, no hydrogen bonding. Such non polar compounds obtain special type of intermolecular interactions called London-Dispersion Forces which are weaker compared to Hydrogen bond interactions.

Result:
Water exist as liquid due to strong Hydrogen bonding between water molecules, while, methane lacks such interactions.

You might be interested in

When NH3(g) reacts with N2O(g) to form N2(g) and H2O(g), 105 kcal of energy are evolved for each mole of NH3(g) that reacts. Wri

Ganezh [65]

Answer : The balanced chemical equation is,

$2NH_3(g)+3N_2O(g)\rightarrow 4N_2(g)+3H_2O(g)+210kcal$

Explanation :

Balanced chemical equation : It is defined as the number of atoms of individual elements present on the reactant side must be equal to the number of atoms of individual elements present on product side.

The given unbalanced chemical reaction is,

$NH_3(g)+N_2O(g)\rightarrow N_2(g)+H_2O(g)+105kcal$

This chemical reaction is an unbalanced reaction because in this reaction, the number of atoms of individual elements are not balanced.

In order to balanced the chemical reaction, the coefficient 2 is put before the $NH_3$ , the coefficient 3 is put before the $N_2O\text{ and }H_2O$ and the coefficient 4 is put before the $N_2$ .