Chemistry - February 2007

I did this practice titration experiment at school-but i'm confused about how I diluted the HCl.

"You are provided with 250 cm^3 of limewater such that it contains approx 1g per dm^3 of calcium hydroxide.
Also available is hydrochloric acid which has a concentration of exactly 2.00 moles per dm^3. This is too concentrated to be used and you will need to dilute it.
You are to plan an investigation which will allow you to determine the concentration, in grams per dm^3, of the limewater as accurately as possible."

I've worked out the balanced equation for the reaction is
Ca(OH)ˇ2 + 2HCl ---> CaClˇ2 + 2Hˇ2O
so the reacting ratio is 1:2:1:2

I know that, if theres 1g per dm^3 of Ca(OH)ˇ2, then I must find the number of moles per gm^3:

Moles=Mass÷RFM=1g÷(40+[16x2]+[1x2])=1÷74=0.135135135 moles
So theres 0.135135135moles per dm^3.
The ratio shows I need double the number of moles of HCl per dm^3 - so it'll be (1÷74)x2=0.027027207per dm^3
How do I dilute the 2 mol.dm^-3 HCl

2007-02-03 06:49:41 · 1 answers · asked by Anonymus 2

I've reacted 4 acids w/ the base NaOH at 2M. The acids are H2SO4, HNO3, HCl, and acetic acid. I did 2 trials for each acid, one with 1M acid and one with 2M acid. I then recorded the temp. change.
Also, I need to figure out the heat released per acidic hydrogen and heat released per mole of water formed.

2007-02-03 06:48:40 · 3 answers · asked by Andrea 1

Can (SO3)^-2 be a trigonal pyramidal??

2007-02-03 06:42:41 · 1 answers · asked by wzerocx 2

2007-02-03 06:34:28 · 3 answers · asked by nikki 1

2007-02-03 06:31:29 · 10 answers · asked by linifer74 1

Hi pplz!
Im a 3rd year chemistry student at uni but am on a placement therefore ive been sent a bunch of notes thru the post. I was meant to have read the notes nd dun these qs in dec and as its feb, my exams r in march and i STILL dont get the notes (they r RUBBISH nd my lecturer is a bit of a meanie so i dont wanna ring him for help) plzzzz can sum1 help me on here!?!
Basically i am totally not understanding my NMR spectroscopy module - i basically learn best by simple examples and simple instructions on how 2 do things ie for proton nmr last year i had 2 buy a book with simple examples like ethanol for me to get intergrations, peak heights etc. I need similar help now - can some1 plz give me step by step instructions on how to assign peaks for COSY, NOEDIF, PENDANT, HMQC and HMBC and also explain really simply wat they r (or point me to a good website where i can learn) - i will b generous with the points for the best asnwer :D
Thanks!!

2007-02-03 06:17:31 · 1 answers · asked by Anonymous

2007-02-03 06:01:40 · 1 answers · asked by redalert 2

2007-02-03 05:56:46 · 21 answers · asked by Anonymous

2007-02-03 05:46:30 · 9 answers · asked by Anonymous

of course not h2o :DUH!

2007-02-03 05:35:58 · 7 answers · asked by ashley g 1

I have the empirical formula.

2007-02-03 05:21:49 · 5 answers · asked by l0bster_quadrille 4

1. Each of the chemical symbols consists of two letters; the first capitalized and the second is lower case.
A. True
B. False

2. The basic building block of matter is the atom.
A. True
B. False

3. Substances in a mixture keep their separate identities and most of their own properties
A. True
B. False

4. Salt and Sugar are insoluble in water.
A. True
B. False

5. The "best mixed" of mixtures is a solution.
A. True
B. False

6. The particles in a colloid are mixed together but not dissolved.
A. True
B. False

7. The particles in a colloid are mixed together but not dissolved.
A. True
B. False

8. Mixtures can be separated by simple chemical means.
A. True
B. False

9. According to its makeup, matter can be classified as elements, compounds, mixtures, and solids.
A. True
B. False

10. The prefix homo- means "different from".
A. True
B. False

11. Gases can be dissolved in water.
A. True
B. False

12. Most of the mass of the atom is located in the electron cloud.
A. True
B. False

2007-02-03 05:21:42 · 1 answers · asked by Mike 2

please and thanks....

2007-02-03 05:15:57 · 4 answers · asked by linifer74 1

does it give off hydrogen quicker when the hydrocloric acid is hotter? (and the acid is the same concentration)

2007-02-03 05:14:36 · 5 answers · asked by Luke J 1

just a chem question i need answered because i was asked this on my chem test and i wanted to make sure!

2007-02-03 05:12:12 · 2 answers · asked by JhoAnNaBaNAnA 1

mass

2007-02-03 05:05:04 · 2 answers · asked by Anonymous

1) Bitumen
2) Candle Wax
3) Polythene

They are all hydrocarbons.

I hope someone can help.

Cheers.

2007-02-03 05:04:55 · 3 answers · asked by emob444 1

2007-02-03 05:02:05 · 1 answers · asked by Anonymous

2007-02-03 05:00:56 · 2 answers · asked by goring 6

i need help in science smart people please help

2007-02-03 04:58:35 · 3 answers · asked by nae-nae from da way-way 1

Please. Some weird, fun facts or whatever about condensation.

2007-02-03 04:53:38 · 2 answers · asked by Anonymous

I am looking for the percent abundance of a hypothetical element. Somewhere I am getting lost. Can somebody break this down for me. When I did it my percentages were off.

Thank you

2007-02-03 04:40:18 · 2 answers · asked by kate m 1

Triethylene glycol and heavy mineral oil are both high boiling, high molecular weight solvents. What differences in their properties (look at their structures) make triethylene glycol a better solvent for a reduction reaction?

2007-02-03 04:25:32 · 1 answers · asked by Frannie 4

2007-02-03 04:23:08 · 6 answers · asked by txw77 1

2007-02-03 04:14:58 · 3 answers · asked by Anonymous

2007-02-03 04:13:29 · 7 answers · asked by Anonymous

2007-02-03 04:12:04 · 5 answers · asked by Anonymous

A sample of sulfur having a mass of 1.28 g combines with oxygen to form a compound with a mass of 3.20 g. What is the empirical formula of the compound?

2007-02-03 04:05:24 · 3 answers · asked by jsock 1

need a scientific answer
Pls help its for my science coursework conclusion

2007-02-03 04:00:39 · 5 answers · asked by Luke J 1

2007-02-03 03:58:55 · 3 answers · asked by shafali v 1