Suppose harry begins with the hydrate kal(so4)2·12h2o. after dehydration he finds that he is left with 3.0 g of the an-hydrate kal(so4)2. how many grams did he start with?

Harry started with of   hydrated salt.

Further explanation:

Mole is the measure of the amount of substance. Mole is the relation between the mass of the substance and molar mass of a substance. It is defined as the mass of a substance in grams divided by its molar mass (g/mol).

The expression to calculate the number of moles is as follows:

Therefore, the formula to calculate the mass of the given compound is,

The molar mass of   is 474.3884g/mol.

The molar mass of   is 258.2050 g/mol.

Therefore, mass of 12  molecules is,

Since initially in , 1 mole of   contained 12 moles of . Thus 258.2050 g of should contains 216 g of before evaporation.

Therefore, the mass of contained by 1 g of   is calculated as,

Therefore, the mass of contained by 3.0 g of   is calculated as follows:

This 2.5 g is the mass of water that is evaporated from hydrated salt.

The total mass of hydrated of taken initially by harry is the sum of the mass of water that is evaporated and mass of dehydrated salt that is left after evaporation process.

Learn more:

1. Determine the number grams of solute in 500 ml of 0.189 M KOH.:

2. Rank the gases in decreasing order of effusion:

Answer details:

Grade: Senior school

Subject: Chemistry

Chapter: Mole concept

Keywords: harry, hydrate salt, KAl(SO4)2•12H2O, dehydration process, hydration process, anhydrated salt, KAl(SO4)2, 3.0 gram KAl(SO4)2, grams of start with, 5.5 g.