Question

When 8.00 g of Pb(C2H5O2)2 xH20 are heated, 1.14 g of H2O are driven off. Find the chemical formula and the name of the hydrate.

Answer 1

Answer:

The formula is $Pb(C_2H_5O_2)_2.3H_2O[tex]

Name = lead(II) hydrate trihydrate

Explanation:

Mass of the hydrated salt = 8.00 g

Mass of water lost = 1.14 g

Mass of the dehydrated salt = 8.00 - 1.14 g = 6.86 g

The moles of the dehydrated salt is :

Amount = 6.86 g

Molar mass of [tex]Pb(C_2H_5O_2)_2[tex] = 329.3198 g/mol

The formula for the calculation of moles is shown below:

[tex]moles = \frac{Mass\ taken}{Molar\ mass}$

Thus, moles are:

$moles= \frac{6.86\ g}{329.3198\ g/mol}$

$moles= 0.0208\ mol$

The moles of water is :

Amount = 1.14 g

Molar mass of $H_2O[tex] = 18 g/mol

The formula for the calculation of moles is shown below:

[tex]moles = \frac{Mass\ taken}{Molar\ mass}$

Thus, moles are:

$moles= \frac{1.14\ g}{18\ g/mol}$

$moles= 0.0633\ mol$

The simplest ration of the two are:

[tex]Pb(C_2H_5O_2)_2:H_2O[tex] = 0.0208 : 0.0633 = 1 : 3

The formula is [tex]Pb(C_2H_5O_2)_2.3H_2O[tex]

Name = lead(II) hydrate trihydrate