Question

You are in space and running out of water. You do have a great deal of magnesium carbonate pentahydrate. It is possible to extract the water from this. Determine the percent of water by mass in the hydrate magnesium carbonate pentahydrate

Answer 1

51.65%

Step-by-step explanation:

Magnesium carbonate pentahydrate is
`MgCO_3.5H_2O`

1 mole of the compound contains 5 moles of water. The water can be extracted by heating the the compound and allowing the water to condense.

`MgCO_3.5H_2O --> MgCO_3 + 5H_2O`

1 mole of the compound contains 5 moles of water molecule

mole = mass/molar mass

1 mole of the compound weighs: 1 x 174.3903 = 174.3903 g

5 moles of water weighs: 5 x 18.01528 = 90.0764 g

Percentage by mass of hydrate in magnesium carbonate pentahydrate

= 90.0764/174.3903 x 100%

= 51.65%