Question

How many cations are present in 28.6 g of silver chromate?

How many anions are present?

What is the mass in grams of one formula unit of silver chromate?

Answer 1

Number of silver ions :
`1.037* 10^(23)`

Number of chromate ions :
`5.18 * 10^(22)`

Mass of single silver chromate :
`5.51* 10^(-22) g`

Step-by-step explanation:

`Ag_2CrO_4` , Silver chromate

Mass of silver chromate = 28.6 g

Molar mass of silver chromate = 332 g/mol

Moles of silver chromate =
`(28.6 g)/(332 g/mol)=0.0861 mol`

`Ag_CrO_4\rightarrow 2Ag^++CrO_4^(2-)`

1 mole of silver chromate has 2 mole of silver ions and 1 mole of chromate ions.

Then silver ions in 0.0861 moles of silver chromate :

`2* 0.0861 moles=0.1722 moles` of silver ion

Then chromate ions in 0.0861 moles of silver chromate :

`1* 0.0861 moles=0.0861 moles` of chromate ion

Number of silver ions :

`=0.1722* 6.022* 10^(23)=1.037* 10^(23)`

Number of chromate ions :

`=0.0861* 6.022* 10^(23)=5.18 * 10^(22)`

Mass of 1 mole of silver chromate = 332 g

1 mole=
`6.022* 10^(23)` molecules/atoms/ions

Mass of single silver chromate :

`(332 g)/(6.022* 10^(23))=5.51* 10^(-22) g`