Ethene, also known as ethylene, is a colorless and flammable gas with a sweet odor. It is a crucial building block in the chemical industry, used in the production of plastics, solvents, and other chemicals.
| IUPAC name | Ethene |
| Molecular formula | C2H4 |
| CAS number | 74-85-1 |
| Synonyms | Ethylene, Ethene (mistakenly), Olefiant gas, Elayl, 1,2-Dihydrogen ethylene |
| InChI | InChI=1S/C2H4/c1-2/h1-2H2 |
Ethene Formula
The chemical formula for ethene is C2H4. It represents the number and type of atoms present in a molecule of ethene. The formula is used in chemical reactions and calculations involving ethene, such as determining the stoichiometry of a reaction or the amount of ethene required for a particular industrial process.
Ethylene Structure
Ethylene has a simple linear structure, with two carbon atoms bonded by a double bond and four hydrogen atoms attached to each carbon atom. The carbon-carbon double bond is responsible for the reactivity of ethylene, which makes it a useful building block in the chemical industry. The molecule has a planar structure, with all atoms lying in the same plane.
Ethene Molar Mass
The molar mass of ethene, also known as ethylene, is 28.05 g/mol. It is a simple organic molecule composed of two carbon atoms and four hydrogen atoms, represented by the chemical formula C2H4. The molar mass is calculated by adding the atomic masses of the individual atoms in the molecule.
Molar mass is an important parameter in chemical reactions and calculations involving ethene. It is used to determine the amount of ethene required in a reaction, as well as the amount of products that can be produced.
Ethene Boiling Point
The boiling point of ethene is -103.7°C (-154.7°F). Ethene is a gas at room temperature and pressure, and its boiling point is well below that of water, which makes it easy to separate from other substances in industrial processes.
The boiling point of ethene depends on the pressure and the purity of the sample. At higher pressures, the boiling point of ethene increases. Similarly, impurities in the sample can cause the boiling point to vary from the expected value.
Ethene Melting Point
The melting point of ethylene is -169.2°C (-272.6°F). Ethylene is a nonpolar molecule with a linear shape, which makes it a relatively simple molecule compared to many other organic compounds. This is reflected in its low melting point.
Like the boiling point, the melting point of ethylene can vary depending on the purity of the sample. Impurities can lower the melting point and make it difficult to obtain a pure sample for experimental purposes.
Ethylene Density g/ml
The density of ethylene is 0.958 g/mL at standard conditions of temperature and pressure (STP), which is defined as 0°C (32°F) and 1 atm pressure. Ethylene is less dense than air, which means that it can rise and disperse in the atmosphere.
Density is an important physical property of ethylene, as it is used in industrial processes to determine the amount of ethylene needed for a given volume of space. It is also used to calculate the mass of ethylene in a sample.
Ethylene Molecular Weight
The molecular weight of ethylene is 28.05 g/mol. It is the sum of the atomic weights of the constituent atoms in the molecule. Molecular weight is an important parameter in many chemical calculations, including determining the stoichiometry of a reaction and the amount of reactants and products required or produced.
| Appearance | Colorless gas |
| Specific gravity | 0.968 g/mL at 20°C (68°F) |
| Color | Colorless |
| Odor | Sweet, pungent |
| Molar mass | 28.05 g/mol |
| Density | 0.958 g/mL at 0°C and 1 atm |
| Melting point | -169.2°C (-272.6°F) |
| Boiling point | -103.7°C (-154.7°F) at 1 atm pressure |
| Flash point | -136°C (-213°F) |
| Water solubility | 3.5 g/L at 25°C (77°F) |
| Solubility | Insoluble in water, soluble in organic solvents |
| Vapour pressure | 114.6 kPa at 20°C (68°F) |
| Vapour density | 0.97 (air = 1) |
| pKa | 44 |
| pH | Not applicable, since ethene is not an aqueous solution |
Ethene Safety and Hazards
Ethylene is a highly flammable gas that can form explosive mixtures with air. It can ignite spontaneously in air if the concentration is high enough. Ethylene is also an asphyxiant and can displace oxygen in confined spaces, posing a risk of suffocation.
Contact with liquid ethylene or exposure to high concentrations of the gas can cause frostbite or burns. Ethylene is not toxic, but its combustion products, including carbon monoxide and carbon dioxide, can be hazardous to human health.
Handling ethylene requires appropriate safety measures, including adequate ventilation, personal protective equipment, and fire safety precautions. Ethylene should be stored and transported in well-ventilated areas away from sources of ignition.
| Hazard Symbols | Flammable Gas (GHS02), Simple Asphyxiant (GHS09) |
| Safety Description | Keep away from sources of ignition – No smoking. Use only non-sparking tools. Do not breathe gas. Use only outdoors or in a well-ventilated area. Wear protective gloves/protective clothing/eye protection/face protection. |
| UN IDs | UN 1962 (compressed gas) |
| HS Code | 2901.21.00 |
| Hazard Class | 2.1 (flammable gas) |
| Packing Group | N/A |
| Toxicity | Not toxic |
Ethene Synthesis Methods
Various methods can synthesize ethylene, including the thermal cracking of hydrocarbons and the dehydration of alcohols.
In thermal cracking, the process involves heating hydrocarbons such as methane, propane, and naphtha to high temperatures (500-900°C) in the presence of a catalyst to break down the long-chain molecules into smaller ones, producing ethylene as one of the products.
Another common method is the dehydration of alcohols, which involves the use of a catalyst such as alumina or silica at high temperatures (250-350°C) to dehydrate ethanol or other alcohols and form ethylene and water.
Steam cracking is another process used to produce ethylene, in which steam is added to hydrocarbons at high temperatures (700-900°C) to generate a mixture of ethylene and other products.
Thermal decomposition of organic materials such as wood, paper, and plastics can also generate ethylene.
Other methods for the synthesis of ethylene include oxidative dehydrogenation of ethane and methanol-to-olefins process.
Ethene Uses
Ethene is an important industrial chemical with a wide range of uses.
- Ethylene plays a crucial role in the production of polyethylene, which is one of the most widely used plastics globally. People use polyethylene in various applications such as packaging, pipes, and construction materials.
- Manufacturers use ethylene as a key ingredient in producing other polymers, such as polyvinyl chloride (PVC). PVC is useful in building materials, medical devices, and electrical cables.
- Ethylene is also crucial in the manufacture of ethylene oxide, a vital raw material in making detergents, solvents, and plastics.
- Manufacturers use ethylene to produce ethylene glycol, a coolant, and antifreeze for engines. It is also a raw material in the manufacture of polyester fibers, films, and resins.
- Ethylene serves as a fuel for welding and cutting metals. It also acts as a ripening agent for fruits and vegetables.
- Ethylene is useful in synthesizing various organic compounds, including ethanol and acetaldehyde.
Overall, the versatility of ethene makes it an essential component in a wide range of industrial processes, contributing to many aspects of modern life.
Questions:
Which dienes will react with ethene in a Diels-Alder reaction?
Any diene containing two conjugated double bonds can undergo a Diels-Alder reaction with ethene. Examples of such dienes include 1,3-butadiene and isoprene.
How are hydrogen atoms arranged in ethene?
In ethene, the two carbon atoms are bonded to each other by a double bond. Each carbon atom is also bonded to two hydrogen atoms, with the remaining valences occupied by two unshared electron pairs on each carbon atom. The arrangement of the atoms around each carbon is trigonal planar.
How many pi bonds are formed when sp2 hybridization occurs in ethene, C2H4?
When sp2 hybridization occurs in ethene, there is one pi bond formed between the two carbon atoms. The sp2 hybrid orbitals are involved in forming sigma bonds between the carbon atoms and the hydrogen atoms, while the p orbitals on each carbon atom overlap to form the pi bond. Ethene is classified as an unsaturated hydrocarbon because it has a double bond between its two carbon atoms. This double bond consists of one sigma bond and one pi bond, which means that ethene has fewer hydrogen atoms than a comparable saturated hydrocarbon with the same number of carbon atoms.