An ionic compound is composed of the element Q, from family 2A, and the element R from family 6A. Write the formula for this ionic compound:

Evaporation: this is when warmth from the sun causes water from oceans, lakes, streams, ice and soils to rise into the air and turn into water vapour (gas). water vapour droplets join together to make clouds! condensation: this is when water vapour in the air cools down and turns back into liquid water.

The mass has escaped into a gas which you can not see so the law stays true.

Less stable  hope this