Identify each of the phase changes described below.
Liquid gold is poured into molds and cools to become solid bars. The gold is
Liquid nitrogen becomes a gas when it is poured out of its container. The nitrogen is
Solid iron is heated to high temperatures so that it becomes a liquid. The iron is
Water vapor in the air becomes tiny liquid droplets that form fog. The water is
In a very cold cryogenic freezer, solid oxygen forms on the walls from the oxygen gas in the air. The
oxygen is
In the high desert, snow changes to water vapor without becoming liquid water. The snow is

Suppose a pair of chemical compounds a and b can react in two different ways: a + b -> c reaction 1 gives product c. a + b -> d reaction 2 gives product d. the following facts are known about the two reactions: . reaction 1 is endothermic and reaction 2 is exothermic. if a reaction vessel is charged (filled) with a and b , then at first d is produced faster than c. use these facts to sketch a qualitative reaction energy diagram for both reactions. note: because these sketches are only qualitative, the energies don? t have to be exact. they only have to have the right relationship to each other. for example, if one energy is less than another, that fact should be clear in your sketch.