Asample of mgco3•3h2o (magnesium carbonate trihydrate) is heated until 40.37 grams of water are released. how many grams did the original hydrate weigh?

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103.168 grams

Explanation:-

When a hydrate salt is heated water is released and anhydrous salt is formed.

The balanced Chemical equation for the reaction is

MgCO3.3H2O --> MgCO3 + 3H2O

Molecular mass of MgCO3.3H2O = 24 x 1 + 12 x 1 + 16 x 3 +3 x ( 1 x 2 + 16 x 1)

= 138 gram

Molecular mass of H2O = 1 x 2 + 16 x 2 = 18 gram

From the balanced chemical equation

3 H2O is released from 1 MgCO3.3H2O.

∴ 3 x 18 gram of H2O is released from 138 gram of MgCO3.3H2O.

40.37 gram of H2O is released from 138 x 40.37 / ( 3 x 18) of MgCO3.3H2O

= 103.168 grams of MgCO3.3H2O

hey there!

mass = 6.75 g

volume =   9 cm³

therefore:

d = mass / volume

d   = 6.75 / 9

d = 0.7 g/cm³

answer b