Question

How many moles of chloride ions are in 0.2550 g of aluminum chloride using AlCl3 's molar mass of 133.34 g / mol:?

Answer 1

I got 0.001912 using dimensional analysis. See the picture for work.

Answer 2

Step-by-step explanation:

It is known that number of moles is the amount of mass present in a given molar mass of the substance.

Mathematically, No. of moles =
`\frac{mass}{\text{molar mass}}`

We are given that mass of
`AlCl_(3)` is 0.255 g and molar mass of
`AlCl_(3)` is 133.34 g/mol.

Therefore, number of moles of
`AlCl_(3)` is calculated as follows.

No. of moles =
`\frac{mass}{\text{molar mass}}`

=
`(0.255 g)/(133.34 g/mol)`

=
`1.912 * 10^(-3)` mol

Since, there are three chlorine atoms present in one mole of
`AlCl_(3)`. Therefore, moles of chlorine ions present in given 0.255 g will be calculated as follows.

`3 * 1.912 * 10^(-3)` mol

=
`5.736 * 10^(-3) mol`

Thus, we can conclude that
`5.736 * 10^(-3) mol` chloride ions are in 0.2550 g of aluminum chloride using
`AlCl_(3)`'s molar mass of 133.34 g/mol.