# help with concentration calculation - Calculation (Aug/03/2006 )

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goodmorning all

how are u all today?
i have a serious problem in calculation.... that i am toooooo bad in it, i need an advice.
i checked some of my old lectures abouts solutions and its preparation.
what shall i do?

-spanishflower-

Check this site. Its good.

Also I use this site for calculations.

I am very bad in calculations myself.

-scolix-

Thankx scolix
my professor can just take a look at the desired solution and give me the answer in one second or so...... u can imagine how do i feel all the time....

thankx again

-spanishflower-

Don't worry, you need practice.
You might have seen in this forum that there are different ways to calculate.
you have to find the one you prefer and to practice a little.

-Missele-

yip as misselle says its just a case of practice make perfect

take some time off and go over your old notes and spend a day dedicated to understanding what you are calculating, not just learning the equations.

trust me, taking some time now to rectify this will be invaluable through out your research career

-grapes of wrath-

you need to visualize how many grams you have in one mole, how many mole in one liter for a 1 molar solution, and then how many grams in 1 liter and so on.

it sounds like a joke, but it is not : use apples instead of moles. It can help

-Missele-

SpanishFlower, good on you for searching. Many of us start off horrible at calculations. I love em. I was horrible at them at first. I bought a few calculation books (Segel "Biochemical Calculations.") And I collect calculations! Yes, from past exam papers (Royal College of Pathologists) from online past-exams (masters courses etc). I try to memorise as "proofs" the steps in a calculation until I know it..kinda like poetry.

There are a core of maybe twenty equations we use frequently. These I keep going over. When my work calls for me to use a new equation I practise and practise until I get a "feel" for the answers. e.g. I've just come back to that old favourite, phosphate buffer. I play with the different masses needed to get different pHs or different molar strengths.
Now, I can look at a pH and molar strength and tell you near enough what mass to use. That's how your prof does it. Just being familiar with the parameters. It's gonna come. Especially since you care so much about it.

Pen to paper and hit the calculator buttons, girl!

"tests show that nine out of ten sums prefer to be done on a calculator by a scientist."

-paraboxa-

Try these concentration lectures. Once you will start to understanding what's going on, download this concentration cheat sheet. And as final resort you can always use concentration calculator.

-Borek-

goodmorning
wow
thankx all for ur support