Anyone good at Chemistry?

[KninjA]

Getting really annoyed by this...

Calculate the volume of hydrogen required to convert 1g of benzen into cyclohexane. (Take molar volume of hydrogen to be 24 L mol)

Equation is:

C6H6+3H2 -> C6H12

My understanding of volumes only extends to basic version of questions and I dont really know how you work that one out. Thanks to anyone who helps.

Furthest I got was:

I mole H2 = 24000cm
1 g = 24000/2=12000cm

As you need 3 moles of hydrogen for every benzene, I thought that you would need 3grams for 1 gram of benzene so:

Volume = 3x 12000 = 36000cm^3

Lol

[quickshot89]

ill give it a bash, im taking this is AS chemistry?

[Cackhandedchimp]

Still stuck KninjA?

[KninjA]

Yh man, if that answers wrong.

[quickshot89]

erm, i think it will be 6 moles of H2 to create 1 mole of C6H12

C6 + 6H2 -> C6H12

volume is easy

1 mole of H2 occupies 24dm^3 (remember that kiddies, 1 mole of any gas always occupies 24dm^3)

24*6 = 144dm^3

hope that helps

the error was in your balancing the eqn

then wot you do is 1/24 = x

then 144/x = answer it think

[Liam]

Chemistry is possibly the most boring thing ever...

PS I hope the following info is useful:

Chemical substance
From Wikipedia, the free encyclopedia
(Redirected from Chemical)
Jump to: navigation, search

Water and steam are two different forms of the same chemical substanceA chemical substance is any material with a definite chemical composition.[1] For example, a sample of water has the same properties and the same ratio of hydrogen to oxygen whether the sample is isolated from a river or made in a laboratory. A pure substance cannot be separated into other substances by any mechanical process.[2] Typical chemical substances found in the home are water, salt (sodium chloride) and sugar (sucrose). Generally, substances exist as solid, liquid, or gas, and may change between these phases of matter with changes in temperature or pressure.

The concept of a chemical substance became firmly established in the late eighteenth century after work by the chemist Joseph Proust on the composition of some pure chemical compounds such as basic copper carbonate.[3] He deduced that: "All samples of a compound have the same composition; that is, all samples have the same proportions, by mass, of the elements present in the compound". This became known as the law of constant composition, and it is one of the foundations of modern chemistry.

Contents [hide]
1 Elements
2 Chemical compounds
3 Mixtures
4 Naming chemical substances
5 Isolation, purification, characterisation and identification
6 References and notes



[edit] Elements
Main article: Chemical element
A chemical substance that cannot be broken down or transformed by ordinary chemical processes into a different substance is called a chemical element (often referred to simply as an element). An element consists of particles called atoms, which consist of negatively charged electrons centered about a nucleus of positively charged protons and uncharged neutrons. All of the atoms in a sample of an element have the same number of protons, though they may be different isotopes, with differing numbers of neutrons.

There are about 120 known elements, about 80 of which are stable, that is, they do not change by radioactive decay into other elements. The majority of elements are classified as metals. These are elements with a characteristic lustre such as iron, copper, and gold. Metals typically conduct electricity and heat well, and they are malleable and ductile.[4] Around a dozen elements[5] such as carbon, nitrogen, and oxygen are classified as non-metals. Non-metals lack the metallic properties described above, they also have a high electronegativity and a tendency to form negative ions called anions. Certain elements such as silicon sometimes resemble metals and sometimes resemble non-metals, and are known as metalloids.

See also: List of elements by name

[edit] Chemical compounds
Main article: Chemical compound
Two or more elements combined into one substance form what is called a chemical compound, which consists of atoms bonded together in molecules. An enormous number of chemical compounds are possible by combining the roughly 120 chemical elements; currently, about thirty million of which have been characterized and identified.[6] Compounds based primarily on carbon and hydrogen atoms are called organic compounds, and all others are called inorganic compounds. Compounds containing bonds between carbon and a metal are called organometallic compounds.

Compounds in which components share electrons are known as covalent compounds. Compounds consisting of oppositely charged ions are known as ionic compounds, or salts.

See also: list of organic compounds
See also: list of inorganic compounds

[edit] Mixtures
Main article: Mixture
All matter consists of various elements and chemical compounds, but these are often intimately mixed together. Mixtures contain more than one chemical substance, and they do not have a fixed composition. In principle, they can be separated into the component substances by purely mechanical processes. Butter, soil and wood are common examples of mixtures.

Grey iron metal and yellow sulfur are both chemical elements, and they can be mixed together in any ratio to form a yellow-grey mixture. No chemical process occurs, and the material can be identified as a mixture by the fact that the sulfur and the iron can be separated by a mechanical process, such as using a magnet to attract the iron away from the sulfur.

In contrast, if iron and sulfur are heated together in a certain ratio (56 grams (1 mol) of iron to 32 grams (1 mol) of sulfur), a chemical reaction takes place and a new substance is formed, the compound iron(II) sulfide, with chemical formula FeS. The resulting compound has all the properties of a chemical substance and is not a mixture. Iron(II) sulfide has its own distinct properties such as melting point and solubility, and the two elements cannot be separated using normal mechanical processes; a magnet will be unable to recover the iron, since there is no metallic iron present in the compound.


[edit] Naming chemical substances
Every chemical substance carries a unique systematic name, usually named according to the IUPAC rules for naming. An alternative system is used by the Chemical Abstracts Service (CAS) .

Many compounds are also known by their more common, simpler names, many of which predate the systematic name. For example, the long-known sugar glucose is now systematically named 6-(hydroxymethyl)oxane-2,3,4,5-tetrol. Natural products and pharmaceuticals are also given simpler names, for example the mild pain-killer Naproxen is the more common name for the chemical compound (S)-6-methoxy-α-methyl-2-naphthaleneacetic acid.

Chemists frequently refer to chemical compounds using chemical formulae, which have more explicit information about the structure of the compound. Computer-friendly systems have been developed for substance information, such as the CAS registry number, SMILES and more recently the International Chemical Identifier or InChI. Besides being used on computer databases, these systems, especially the CAS number, have also become useful in paperwork as unique codes for identifying specific substances.

Identification of a typical chemical substance Common name Systematic name Chemical formula Chemical structure CAS registry number InChI
alcohol, or
ethyl alcohol ethanol C2H5OH [64-17-5] 1/C2H6O/c1-2-3/h3H,2H2,1H3


[edit] Isolation, purification, characterisation and identification
Often a pure substance needs to be isolated from a mixture, for example from a natural source (where a sample often contains numerous chemical substances) or after a chemical reaction (which often give mixtures of chemical substances). This is usually done using physical processes such as distillation, filtration, liquid-liquid extraction, and evaporation. These same techniques, along with others such as recrystallisation, may also be used to purify the substance. Once the pure material has been prepared, its chemical and physical properties may be examined in order to characterise the substance. Finally, chemical analysis may be used to identify the chemical composition and to assay the purity.


[edit] References and notes
^ Hill, J. W.; Petrucci, R. H.; McCreary, T. W.; Perry, S. S. General Chemistry, 4th ed., p5, Pearson Prentice Hall, Upper Saddle River, New Jersey, 2005.
^ Ebbing, D. D.; Gammon, S. D. General Chemistry, 7th ed., p12, Houghton Mifflin, Boston, Massachusetts, 2002.
^ Hill, J. W.; Petrucci, R. H.; McCreary, T. W.; Perry, S. S. General Chemistry, 4th ed., p37, Pearson Prentice Hall, Upper Saddle River, New Jersey, 2005.
^ Hill, J. W.; Petrucci, R. H.; McCreary, T. W.; Perry, S. S. General Chemistry, 4th ed., pp45-46, Pearson Prentice Hall, Upper Saddle River, New Jersey, 2005.
^ The boundary between metalloids and non-metals is imprecise, as explained in the previous reference.
^ Chemical Abstracts substance count

[quickshot89]

liam i dont see what that has to do with the answer at all, it gives no help what so ever, you even said you dont like, so why post that crap

anyway, the answer i gave seems right when looking over my notes, just double check to see if its right

[Pirate Balloon]

Nah, i'm not very good at Chemisty, sorry.

[Liam]

liam i dont see what that has to do with the answer at all, it gives no help what so ever, you even said you dont like, so why post that crap

anyway, the answer i gave seems right when looking over my notes, just double check to see if its right

I was only trying to help you crock o' dung.

[KninjA]

Nah the formula for benzene is C6H6 man. Anyway, it dont matter, did my mock today and I think I've done alright, considering its the Scottish equivalent of Alevel and I only studied for a day....lol?

[quickshot89]

erm, so why have you put C6H12 in your 1st post?

could of sworn benzene was C6H12 with an empirical formulae of CH2

[KninjA]

The equation probably doesnt make sense cos you havent got the paper in front of you. The reaction essentially is hydrogen with benzene to form cyclohexane.

C6H6 + 3H2 -> C6H12
^Benzene ^Hydrogen ^Cyclohexane
(def the right formula for benzene btw)

Im not sure if there was meant to be another product though.

[quickshot89]

o ok, i read it as carbon + hydrogen to make bezene

in that case, the answer is

72dm^3

[Adamack]

Nah the formula for benzene is C6H6 man. Anyway, it dont matter, did my mock today and I think I've done alright, considering its the Scottish equivalent of Alevel and I only studied for a day....lol?

You studied for one day? lol

[KninjA]

You studied for one day? lol

Lol yeh, the funny thing is, I'm pretty sure I still got at least a C. I did the same for all my subjects just cos I've been stupid, but I still got an A in biology and computing...I failed maths tho lol.

then wot you do is 1/24 = x

then 144/x = answer it think

Could you explain whats goin on there?