Use the equation to help you calculate the heat of combustion of ethylene, C2H4. The bond energies are: C-H -416 kJ/mol; C-C 356 kJ/mol; C=C 598 kJ/mol; O=O 498 kJ/mol; C=O 803 kJ/mol; H — O 467 kJ/mol.

Large helium-filled balloons are used to lift scientific equipment to high altitudes. what is the pressure inside such a balloon if it starts out at sea level with a temperature of 10.0ºc and rises to an altitude where its volume is twenty times the original volume and its temperature is – 50.0ºc ?