# Thread: trying to make a 3000mL solution...

1. ## trying to make a 3000mL solution...

Ok, I am definitely victim to the use it or lose it crowd when it comes to math. This is a simple problem but I'm lacking the confidence my logic with it.

so, I want to make a 3L solution.

To make a 1L solution, I add 100mL of this 10X reagent with 900mL of water.
I must then add 700g of a powder to this solution. In the end, the final volume comes out to be 1400mL.

For the sake of my own curiosity, how do I go about solving this?

Here's what I've reasoned...

700g for 1400mL
to make 3000mL, 3000/1400 = 2.14

700g x 2.14 = 1498g

100 x 2.14 = 214mL of 10x soln
900 x 2.14 = 1926mL of water
~~~~ with the outrageous amount of powder, I should get 3L.

Am I right or wrong? Please help me out with this. thanks

2. actually... I think I'm right.

it would be nice for someone to confirm this though.

3. Hello TreeTruffle

Yes, you're about right, but have rounded too soon, meaning that your answers aren't quite as accurate as they might be.

Amount of powder $\displaystyle = \frac{700 \times 3000}{1400}=1500$ gm

Amount of 10x solution = $\displaystyle = \frac{100 \times 3000}{1400}=214$ ml (which is what you got)

Amount of water $\displaystyle = \frac{900 \times 3000}{1400}=1929$ ml

Grandad