Question

A 1.20 gram sample of a hydrated salt is heated to a constant mass of .80 gram. what is the percent of mass of water contained in the original sample

Answer 1

The mass of the water is 1.20 - 0.80 = 0.40 grams.

The % of water is (0.40 / 1.20 ) * 100 = 33 1/3% 

Answer 2

Answer:

33.33 % of mass of water contained in the original sample

Explanation:

Evaporation is the physical process by which water changes from a liquid to a gaseous state,  returning directly to the atmosphere in the form of steam. Also the water in solid state (snow or ice) can pass directly to steam and the phenomenon is called sublimation. To  effects of estimating evaporation losses in an area, the term shall be understood as  broad sense, including sublimation. Solar radiation provides the molecules of  water the energy necessary for the change of state.

Calculations:

Evaporated water: initial mass - final mass

Evaporated water:          1.2 g  -  0.8 g  

Evaporated H20 =                0.4 g

1.2 g total mass --> 100 %

0.4 g of H20 --> 33.33 %

The percent of mass of water contained in the original sample is 33.33 %