Transfer Of Heat

Domestic microwave cooking uses

What is the lowest possible temperature?

Approximately how much potassium chlorate need to be heated to obtain 22.4 litre of oxygen at N.T.P. ?

A thermally insulated room has only one square glass window of sides 1 m and thickness 5 mm through which heat can transfer in and out. If temperature difference between inside and outside the room is only 1°C then what will be the rate of heat energy transfer ? (Thermal conductivity of glass is 0.0025 )