What are some objects that get colder when thermal energy is added? (besides an icepack)

What does x represent in the formula for the compound xcl4?

Melting and boiling are endothermic processes. this means that these processes absorb energy from their surroundings in order to occur. use this information and the data you collected in the phase change gizmo to describe what happens to the temperature of water when you boil it, then explain why this result occurs.

In chemistry, the type of an atom (what element it is) is determined by: a) the number of protons it contains in its nucleus.b) the number of neutrons it contains in its nucleus.c) the number of protons it has in a cloud around the nucleus.d) the number of neutrons it has in a cloud around the nucleus.e) the number of electrons it exchanges with its neighbors.