The heat of fusion is defined as the energy required at a constant temperature to change 1 unit mass of a 1. gas to a liquid 2. gas to a solid 3. solid to a gas 4. solid to a liquid​

the ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (uvr) from the sun, protecting life on earth from its potentially harmful effects. when the sky is clear, there is an inverse relationship between stratospheric ozone and solar uvr measured at the earth's surface.

answer; the numbers of valence electrons in the acetic acid molecule (ch3co2h) is 24;