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Further reading |
Cox, David R. & Reid, Nancy M. (2000). The theory of design of experiments. (Chapman & Hall/CRC). |
Freedman, David A.; Pisani, Robert; Purves, Roger (2007) Statistics, 4th edition. W.W. Norton & Company |
Tabachnick, Barbara G. & Fidell, Linda S. (2007). Using Multivariate Statistics (5th ed.). Boston: Pearson International Edition. |
External links |
SOCR ANOVA Activity |
Examples of all ANOVA and ANCOVA models with up to three treatment factors, including randomized block, split plot, repeated measures, and Latin squares, and their analysis in R (University of Southampton) |
NIST/SEMATECH e-Handbook of Statistical Methods, section 7.4.3: "Are the means equal?" |
Analysis of variance: Introduction |
Design of experiments |
Statistical tests |
Parametric statistics In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which all the carbon–carbon bonds are single. Alkanes have the... |
The International Union of Pure and Applied Chemistry (IUPAC) defines alkanes as "acyclic branched or unbranched hydrocarbons having the general formula , and therefore consisting entirely of hydrogen atoms and saturated carbon atoms". However, some sources use the term to denote any saturated hydrocarbon, including th... |
In an alkane, each carbon atom is sp3-hybridized with 4 sigma bonds (either C–C or C–H), and each hydrogen atom is joined to one of the carbon atoms (in a C–H bond). The longest series of linked carbon atoms in a molecule is known as its carbon skeleton or carbon backbone. The number of carbon atoms may be considered a... |
One group of the higher alkanes are waxes, solids at standard ambient temperature and pressure (SATP), for which the number of carbon atoms in the carbon backbone is greater than about 17. |
With their repeated – units, the alkanes constitute a homologous series of organic compounds in which the members differ in molecular mass by multiples of 14.03 u (the total mass of each such methylene-bridge unit, which comprises a single carbon atom of mass 12.01 u and two hydrogen atoms of mass ~1.01 u each). |
Methane is produced by methanogenic bacteria and some long-chain alkanes function as pheromones in certain animal species or as protective waxes in plants and fungi. Nevertheless, most alkanes do not have much biological activity. They can be viewed as molecular trees upon which can be hung the more active/reactive fu... |
The alkanes have two main commercial sources: petroleum (crude oil) and natural gas. |
An alkyl group is an alkane-based molecular fragment that bears one open valence for bonding. They are generally abbreviated with the symbol for any organyl group, R, although Alk is sometimes used to specifically symbolize an alkyl group (as opposed to an alkenyl group or aryl group). |
Structure and classification |
Ordinarily the C-C single bond distance is . |
Saturated hydrocarbons can be linear, branched, or cyclic. The third group is sometimes called cycloalkanes. Very complicated structures are possible by combining linear, branch, cyclic alkanes. |
Isomerism |
Alkanes with more than three carbon atoms can be arranged in various ways, forming structural isomers. The simplest isomer of an alkane is the one in which the carbon atoms are arranged in a single chain with no branches. This isomer is sometimes called the n-isomer (n for "normal", although it is not necessarily the m... |
C1: methane only |
C2: ethane only |
C3: propane only |
C4: 2 isomers: butane and isobutane |
C5: 3 isomers: pentane, isopentane, and neopentane |
C6: 5 isomers: hexane, 2-methylpentane, 3-methylpentane, 2,2-dimethylbutane, and 2,3-dimethylbutane |
C7: 9 isomers: heptane, methylhexane (2 isomers), dimethylpentane (4 isomers), 3-ethylpentane, 2,2,3-trimethylbutane |
C8: 18 isomers: octane, 2-methylheptane, 3-methylheptane, 2,3-dimethylhexane, 3,4-dimethylhexane, 2,3,4-trimethylpentane, 3,3-dimethylhexane, 2,2-trimethylpentane, 2,4-dimethylhexane, 2,2,4-trimethylpentane, 2,3,3-Trimethylpentane, 3,3,4-trimethyl-pentane, 3,4,4-trimethylpentane, 2,4,4-trimethylpentane, (5 isomers) |
C9: 35 isomers |
C10: 75 isomers |
C12: 355 isomers |
C32: 27,711,253,769 isomers |
C60: 22,158,734,535,770,411,074,184 isomers, many of which are not stable. |
Branched alkanes can be chiral. For example, 3-methylhexane and its higher homologues are chiral due to their stereogenic center at carbon atom number 3. The above list only includes differences of connectivity, not stereochemistry. In addition to the alkane isomers, the chain of carbon atoms may form one or more rings... |
Nomenclature |
The IUPAC nomenclature (systematic way of naming compounds) for alkanes is based on identifying hydrocarbon chains. Unbranched, saturated hydrocarbon chains are named systematically with a Greek numerical prefix denoting the number of carbons and the suffix "-ane". |
In 1866, August Wilhelm von Hofmann suggested systematizing nomenclature by using the whole sequence of vowels a, e, i, o and u to create suffixes -ane, -ene, -ine (or -yne), -one, -une, for the hydrocarbons CnH2n+2, CnH2n, CnH2n−2, CnH2n−4, CnH2n−6. In modern nomenclature, the first three specifically name hydrocarbon... |
Linear alkanes |
Straight-chain alkanes are sometimes indicated by the prefix "n-" or "n-"(for "normal") where a non-linear isomer exists. Although this is not strictly necessary and is not part of the IUPAC naming system, the usage is still common in cases where one wishes to emphasize or distinguish between the straight-chain and bra... |
The first six members of the series (in terms of number of carbon atoms) are named as follows: |
methane CH4 – one carbon and 4 hydrogen |
ethane C2H6 – two carbon and 6 hydrogen |
propane C3H8 – three carbon and 8 hydrogen |
butane C4H10 – four carbon and 10 hydrogen |
pentane C5H12 – five carbon and 12 hydrogen |
hexane C6H14 – six carbon and 14 hydrogen |
The first four names were derived from methanol, ether, propionic acid and butyric acid. Alkanes with five or more carbon atoms are named by adding the suffix -ane to the appropriate numerical multiplier prefix with elision of any terminal vowel (-a or -o) from the basic numerical term. Hence, pentane, C5H12; hexane, C... |
Branched alkanes |
Simple branched alkanes often have a common name using a prefix to distinguish them from linear alkanes, for example n-pentane, isopentane, and neopentane. |
IUPAC naming conventions can be used to produce a systematic name. |
The key steps in the naming of more complicated branched alkanes are as follows: |
Identify the longest continuous chain of carbon atoms |
Name this longest root chain using standard naming rules |
Name each side chain by changing the suffix of the name of the alkane from "-ane" to "-yl" |
Number the longest continuous chain in order to give the lowest possible numbers for the side-chains |
Number and name the side chains before the name of the root chain |
If there are multiple side chains of the same type, use prefixes such as "di-" and "tri-" to indicate it as such, and number each one. |
Add side chain names in alphabetical (disregarding "di-" etc. prefixes) order in front of the name of the root chain |
Saturated cyclic hydrocarbons |
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