Energy is required to change the phase of a substance, such as the energy to break the bonds between molecules in a block of ice so it may melt.
During a phase change energy my be added or subtracted from a system, but the temperature will not change. The temperature will change only when the phase change has completed. No temperature change occurs from heat transfer if ice melts and becomes liquid water (i.e., during a phase change). For example, consider water dripping from icicles melting on a roof warmed by the Sun. Conversely, water freezes in an ice tray cooled by lower-temperature surroundings. Energy is required to melt a solid because the cohesive bonds between the molecules in the solid must be broken apart so that the molecules can move around at comparable kinetic energies; thus, there is no rise in temperature.
Answer:
uh A.)? [ZnCI2+H2]? /////////
The relative humidity shows us saturation of water in air. Since it is 58% and not 100% we have to scale density that we were given when humidity is 100%.
At 100% humidity, density is 20grams/cubic meter
at 58% it will be:
0.58 * 20 = 11.6 g/m^3
Since the question is to find density, the answer cannot be in %.
Answer is 11.6 g/m^3
The answer would be Rocks, metals, hydrogen compounds, hydrogen and helium, all in gaseous form.
