Homework Help: Density question

Nellen2222 · Sep 12, 2012

1. The problem statement, all variables and given/known data

The density of a solution of ferric chloride is 1.058g/cc, and it is 7.00 percent by mass. What volume of the soltion (in mL) do you need to supply 34.0g of ferric chloride?

2. Relevant equations

D=m/v

3. The attempt at a solution

Not sure where to begin. I dont understand the statement, " and it is 7 percent by mass". Does this mean i ned to multiply 34*0.07? then just calculate the volume by rearranging the density formula?

voko · Sep 12, 2012

It means that 100 g of the solution contains 7 g of ferric chloride.

Nellen2222 · Sep 12, 2012

Where do I even begin on this question?

voko · Sep 12, 2012

You know the absolute mass of ferric chloride you need to supply.

You know the mass percentage of it in the solution => you know the mass of the solution containing the required amount of ferric chloride.

Can you see what happens next?

Nellen2222 · Sep 12, 2012

muultiply mass by mass percentage?

Chestermiller · Sep 12, 2012

You do understand that the solution is partly water and partly ferric chloride, right?

If, as voko pointed out, 100 gm of the solution contains 7 gm of ferric chloride, how many grams of solution contain 34 grams of ferric chloride?

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Homework Help: Density question

Nellen2222

voko

Nellen2222

voko

Nellen2222

Chestermiller

Staff: Mentor