The viscosity of gases … with temperature, whereas the viscosity of liquids … with temperature (increases/decreases)
η of gases increase and η of liquids decrease with an increases in temperature. As temperature increases, the average speed of molecules in a liquid also increase and as a result, they spend less time with their "neighbors." Therefore, as temperature increases, the average intermolecular forces decrease and the molecules are able to interact without being "weighed down" by one another. However, the viscosity of a gas increases as temperature increases because there is an increase in frequency of intermolecular collisions at higher temperatures. Since the molecules are flying around in the void most of the time, any increase in the contact they have with one another will increase the intermolecular force which will ultimately lead to a disability for the whole substance to move.
