Question

Methane, CH_4, is a gas room temperature but dichloromethane, CH_2Cl_2 is a liquid. Why? Water will rise up into a capillary tube. Why, and how is this phenomenon important in nature? Calculate the amount of heat in kJ that is required to heat 20.0g of ice from -25 degree C to 90 degree C, and sketch a heating curve for the process. The specific heat of ice is 2.11 J/(g, degree C); water 4.18 J/(g, degree C) and the Delta H_fus for water is 6.01 kJ/mol Calculate the amount of heat liberated when a 10.0 g of steam in converted to water at 75.0 degree C and sketch a cooling curve for the process. The specific heat of steam is 2.00 J/(g, degree C); water are 4.18 J/g. degree C) and the Delta H_vap for water is 40.6 kJ/mol.

Answer 1

Intermolecular forces plays major role Methane has very low intermolecular forces (dipole-dipole interaction and London dispersion forces) hence methane has low boiling point. On the other dichloromethane is liquid: Increase in substitution in methane gives permanent dipole -dipole interaction and London dispersion forces, Increase boiling point and also Branching on carbon chain lowers the BP Dipole moment present in dichloromethane is higher than methane which has zero dipole moment.so, dichloromethane is liquid at room temperature.