BBC Bitesize - GCSE Chemistry (Single Science) - Organic compounds - OCR Gateway - Revision 1
Learn about organic compounds with Bitesize GCSE Chemistry (OCR Gateway). Hydrocarbon, any of a class of organic chemical compounds composed only of . Structural formulas for methane (CH4), ethane (C2H6) There is no simple arithmetic relationship between the number of carbon atoms in a formula and the . A secondary school revision resource for Edexcel GCSE chemistry about hydrocarbons. The general formula means that the number of hydrogen atoms in an alkane is double the For example, methane is CH4 and ethane is C2H6. Alkane.
All of these are sigma bonds.
Methane | CH4 - PubChem
Because they are formed from the end-on-end overlap of two orbitals, sigma bonds are free to rotate. This means, in the case of ethane molecule, that the two methyl CH3 groups can be pictured as two wheels on a hub, each one able to rotate freely with respect to the other.
The sp3 bonding picture is also used to described the bonding in amines, including ammonia, the simplest amine. Just like the carbon atom in methane, the central nitrogen in ammonia is sp3-hybridized.
With nitrogen, however, there are five rather than four valence electrons to account for, meaning that three of the four hybrid orbitals are half-filled and available for bonding, while the fourth is fully occupied by a non-bonding pair of electrons. C2H4, also known as ethylene or ethene, is a gaseous material created synthetically through steam cracking.
In nature, it is released in trace amounts by plants to signal their fruits to ripen. The remaining unhybridized p orbitals on the carbon form a pi bond, which gives ethene its reactivity.
Crude Oil and Natural Gas: From Source to Final Products
Bonding in Ethene A key component of using Valence Bond Theory correctly is being able to use the Lewis dot diagram correctly. The correct Lewis structure for ethene is shown below: Valence Shell Electron Pair Repulsion VSEPR Theory is used to predict the bond angles and spatial positions of the carbon and hydrogen atoms of ethene and to determine the bond order of the carbon atoms the number of bonds formed between them.CH4 + O2 = CO2 + H2O - Balanced Equation (Methane Combustion Reaction)
According to valence bond theory, two atoms form a covalent bond through the overlap of individual half-filled valence atomic orbitals, each containing one unpaired electron. The fourth electron is in the p orbital that will form the pi bond. The bond order for ethene is simply the number of bonds between each atom: The terms aliphatic and aromatic are retained in modern terminology, but the compounds they describe are distinguished on the basis of structure rather than origin.
Aliphatic hydrocarbons are divided into three main groups according to the types of bonds they contain: Alkanes have only single bonds, alkenes contain a carbon-carbon double bond, and alkynes contain a carbon-carbon triple bond. Aromatic hydrocarbons are those that are significantly more stable than their Lewis structures would suggest; i.
This classification of hydrocarbons serves as an aid in associating structural features with properties but does not require that a particular substance be assigned to a single class.
Ethane, Ethylene, and Acetylene - Chemistry LibreTexts
Indeed, it is common for a molecule to incorporate structural units characteristic of two or more hydrocarbon families. A molecule that contains both a carbon-carbon triple bond and a benzene ring, for example, would exhibit some properties that are characteristic of alkynes and others that are characteristic of arenes. Alkanes are described as saturated hydrocarbons, while alkenes, alkynes, and aromatic hydrocarbons are said to be unsaturated. In order of increasing number of carbon atoms, methane CH4ethane C2H6and propane C3H8 are the first three members of the series.
Methane, ethane, and propane are the only alkanes uniquely defined by their molecular formula.
For C4H10 two different alkanes satisfy the rules of chemical bonding namely, that carbon has four bonds and hydrogen has one in neutral molecules.
One compound, called n- butanewhere the prefix n- represents normal, has its four carbon atoms bonded in a continuous chain. The other, called isobutanehas a branched chain.