Question

What is the concentration of 450.0 mL of solution that contains 225 grams of iron (I)chloride (FeCl, molar mass=91.3)?

Answer 1

`5.47 \ "M"`

Explanation:

Well, we got `225 \ "g"` of iron, and so we need to convert that amount into moles of iron, and that comes out to

`(225color(red)cancelcolor(black)"g")/(91.3color(red)cancelcolor(black)"g""/mol")~~2.46 \ "mol"`

Now to find the molarity, we use the molarity equation, which states that:

`"molarity"="moles of solute"/"liters of solution"`

So, we have to convert `450 \ "mL"` into `"L"`. We know that `1 \ "L"=1000 \ "mL"`. Therefore, we got

`450color(red)cancelcolor(black)"mL"*(1 \ "L")/(color(red)cancelcolor(black)"mL")=0.45 \ "L"`

The molarity is therefore,

`"molarity"=(2.46 \ "mol")/(0.45 \ "L")`

`~~5.47 \ "mol/L"`

`=5.47 \ "M"`