Question

There sets of sketches below, showing the same pure molecular compound (water, molecular formula H_2 O) at three different temperatures. The sketches are drawn as if a sample of water were under a microscope so powerful that individual atoms could be seen. Only one sketch in each set is correct. Use the slider to choose the correct sketch in each set. You may need the following information: melting point of H_2 O: 0.0 degree C boiling point of H_2 O: 100.0 degree C

Answer 1

C is water in solid phase i.e. ice at -25Celsius. This is because water freezes at 0Celsius and at -25Celsius water is in its solid phase i.e. ice. since it is the solid phase, atoms are closely packed and at minimum distance from each other.

A is water in liquid phase i.e.as water at 55Celsius. the atoms are still closely packed but as tight as in solid phase.

B is water in gaseous phase i.e. as vapour at 223Celsius. Water boils at 100C , so at 223C, water exist as water vapour. since its gaseous phase, atoms are far apart and at large distance to each other.