# How to read a curve level accurately

1. Oct 26, 2009

### Stress D.

1. The problem statement, all variables and given/known data
i got this in chemistry homework and have never done it before...

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______________________Experiment 1___Experiment 2___Experiment 3

Final volume of
hydrochloric acid/cm(3) 48.25 44.30 46.05
_______________________________________________________________

Initial volume of
hydrochloric acid/cm(3) 18.30 14.25 16.05
_______________________________________________________________

Volume of hydrochloric
acid used/cm(3) 29.95 30.05 30.00
_______________________________________________________________

Draw a diagram to show the meniscus at the top of a column of hydrochloric acid in a caliberated tube. Explain how to read the level of the acid accurately.

2. Oct 26, 2009

### Staff: Mentor

3. Oct 27, 2009

### Stress D.

tank u very much borek.....am not 2 b annoyin but i have another question hear i just got to and dont no d answer to....

Calculate the value of x in the formula Al2(SO4)3.K[2]SO4.xH2O.

4. Oct 27, 2009

### Staff: Mentor

Please use plain English, you don't want to me to waste time eciphering what you mean, don't you?

You need some more information to calculate x, at the moment (just looking at the formula) it can't be done.

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5. Oct 27, 2009

### Stress D.

I am sorry i forgot about the chatting slang......

oh and i missed out this part to the question here is the whole question

Al2(SO4)3.K2SO4.xH2O -------------> Al2(SO4)3.K2SO4 + xH2O
Hydrated Anhydrous
compound compound

When 9.48g of the hydrated compound was heated at 200 degrees celcius.
5.16g of the anhydrous compound was formed.

Calculate the value of x in the formula Al2(SO4)3.K2SO4.xH2O

6. Oct 27, 2009

### Staff: Mentor

What is formula of anhydrous salt?

What is its molar mass?

How many moles of water were lost during heating?

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methods

7. Oct 27, 2009

### Stress D.

it did not give all of that information what i typed was the most info it gave.....
i had to work out its relative mass = 516g
and that the reaction occurs at 200 degrees celcius and that is it

8. Oct 28, 2009

### Staff: Mentor

If I understand correctly - 516g is a molar mass of hydrated salt?

Try to follow questions I have posted earlier.

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