Fourth Official Post (For Chemistry Journal)
The third type of chemical bond is ionic bond. An ionic bond involves a metal and non-metal ion through electrostatic attraction. Other words, it is a bond formed by the attracting of two oppositely charged ions.
One or more electrons are contributed by the metal creating a positive charged ion and then, the electrons enter the non-metal forming a negatively charged ion. The electrostatic attraction between the positively and negatively charged ions causes them to come together and form a bond. Cation is a positively charged ion, while anion is a negatively charged ion.
For instance, common salt is sodium chloride. The sodium atoms each lose an electron creating a cation when they combine. Chlorine atoms will then each gain an electron and become an anion. In a 1:1 ratio, the ions attract each other as they are oppositely charged to from sodium chloride. That is how ionic bond can be used.
The ions will have an increase in energy when electrons are being removed from their atoms. The process of removal is called endothermic. Energy increase may also be due to the breaking of current bonds and the addition of electrons to form anion. The energy will be lowered by the attraction of the ions.
The change in overall energy must be favorable, when the bonded atoms have a lower energy than those which are free, in order for ionic bonding to occur. The stronger the bond will be when the resulting energy change is greater. The energy change of the reaction is most favorable when metals lose electrons and non-metals gain electrons as metals have low electro negativity and non-metals have high electronegativity.
However, pure ionic bonding is not said to exist. All ionic compounds have a certain degree of covalent bonding. Ionic compounds have a high melting point, tend to be soluble in water and can conduct electricity when molten or in solution.
Ionic bonding can actually create a new product whereby the product becomes something edible from something inedible as can be seen for common table salt.
Friday, July 31, 2009
Entry 3- Covalent Bond
Third Official Post (For Chemistry Journal)
The second type of bonding which I will be talking about is covalent bond. Covalent bond is the sharing of pairs of electrons between atoms or atoms with other covalent bonds. In other words, it is the attraction-to-repulsion stability that forms between atoms when they share electrons. As discussed in valence bond theory, covalent bond means that atoms share valence.
Through covalent bonding in the molecule H2 (the 2 is supposed to be sub-script), the hydrogen atoms share the two electrons. Covalent bonding does not require the two atoms to be from the same element but just that the two atoms are of comparable electro negativity. In contrast to “ionic bonds”, the strength of covalent bond is dependant on the angular relation between atoms in polyatomic molecules.
The number of pairs of electrons shared between atoms forming a covalent bond is indicated by the bond order.
Ø Single bond- Most common and indicates the sharing of only a pair of electrons between two atoms. Usually has a sigma bond
Ø Double bond- Typically has a sigma bond and a pi bond, where two lobes of one involved electron orbital overlap two lobes of the other involved electron orbital.
Ø Triple bond- Usually has a sigma bond and two pi bonds
Ø Quadruple bond- Found in transition metals like molybdenum
Ø Quintuple bond- Found to exist in some dichromium (a chemical) compounds
Ø Sextuple bond- Found in diatomic tungsten and molybdenum
The above covalent bonds are actually powerful and pervasive. In my next entry, I will be talking about ionic bonding.
The second type of bonding which I will be talking about is covalent bond. Covalent bond is the sharing of pairs of electrons between atoms or atoms with other covalent bonds. In other words, it is the attraction-to-repulsion stability that forms between atoms when they share electrons. As discussed in valence bond theory, covalent bond means that atoms share valence.
Through covalent bonding in the molecule H2 (the 2 is supposed to be sub-script), the hydrogen atoms share the two electrons. Covalent bonding does not require the two atoms to be from the same element but just that the two atoms are of comparable electro negativity. In contrast to “ionic bonds”, the strength of covalent bond is dependant on the angular relation between atoms in polyatomic molecules.
The number of pairs of electrons shared between atoms forming a covalent bond is indicated by the bond order.
Ø Single bond- Most common and indicates the sharing of only a pair of electrons between two atoms. Usually has a sigma bond
Ø Double bond- Typically has a sigma bond and a pi bond, where two lobes of one involved electron orbital overlap two lobes of the other involved electron orbital.
Ø Triple bond- Usually has a sigma bond and two pi bonds
Ø Quadruple bond- Found in transition metals like molybdenum
Ø Quintuple bond- Found to exist in some dichromium (a chemical) compounds
Ø Sextuple bond- Found in diatomic tungsten and molybdenum
The above covalent bonds are actually powerful and pervasive. In my next entry, I will be talking about ionic bonding.
Tuesday, July 28, 2009
Entry 2- Hydrogen Bond
Second Official Post (For Chemistry Journal)
What do you understand by the word: hydrogen? Water. Hydrogen bond refers to the attractive interaction of a hydrogen atom with an electronegative atom such as oxygen. The hydrogen is bonded to another atom which is electronegative.
Hydrogen bond can occur between molecules or even between the different parts in a molecule itself. It can also occur in inorganic molecules and organic molecules like water and DNA respectively. What causes the high boiling point of 100 degree Celsius of water is actually hydrogen bonding.
A hydrogen bond donor is a hydrogen atom attached to an electronegative atom which is typically fluorine, oxygen or nitrogen. A hydrogen bond accepter is the electronegative atom, ignoring whether it bonds with the hydrogen atom successfully. Ethanol is an example whereby hydrogen is bonded with oxygen.
Hydrogen bonding can also occur in the case when hydrogen is attached to carbon. The electronegative atom attracts the electron cloud around the nucleus of hydrogen and decentralized the cloud, leaving the atoms with a positive charge. When this strong positive charge attracts a lone pair of electrons (in this case, the hydrogen bond acceptor), a hydrogen bond is formed.
The hydrogen bonds’ length depends on its strength, temperature and pressure and the strength of the bonds is variable according to its temperature, pressure and bond angle etc.
Let us now look at one of the simplest hydrogen bond, which is one formed in the water. In a water molecule, two hydrogen atoms and one oxygen atom is present. The molecules in the water can bond with up to four other molecules as each oxygen molecule has a lone pair of electrons which can form a hydrogen bond with two hydrogen atoms from other molecules. The great strength and the large number of hydrogen bonds in the water lead to the high boiling point of water. A lot of energy is needed to break the bonds. Water is unique. It has oxygen atom which bonds with two lone pairs and two hydrogen atoms. This shows that the total number of bonds in a water molecule can go up to four. With more bonds, more energy is needed to break them.
Therefore, the high boiling point of water is caused by hydrogen bonds. For example, hydrogen fluoride also has hydrogen bonds. Hydrogen bond basically brings a hydrogen atom and an electronegative atom together. However, hydrogen bonding must not be confused with covalent bonding.
What do you understand by the word: hydrogen? Water. Hydrogen bond refers to the attractive interaction of a hydrogen atom with an electronegative atom such as oxygen. The hydrogen is bonded to another atom which is electronegative.
Hydrogen bond can occur between molecules or even between the different parts in a molecule itself. It can also occur in inorganic molecules and organic molecules like water and DNA respectively. What causes the high boiling point of 100 degree Celsius of water is actually hydrogen bonding.
A hydrogen bond donor is a hydrogen atom attached to an electronegative atom which is typically fluorine, oxygen or nitrogen. A hydrogen bond accepter is the electronegative atom, ignoring whether it bonds with the hydrogen atom successfully. Ethanol is an example whereby hydrogen is bonded with oxygen.
Hydrogen bonding can also occur in the case when hydrogen is attached to carbon. The electronegative atom attracts the electron cloud around the nucleus of hydrogen and decentralized the cloud, leaving the atoms with a positive charge. When this strong positive charge attracts a lone pair of electrons (in this case, the hydrogen bond acceptor), a hydrogen bond is formed.
The hydrogen bonds’ length depends on its strength, temperature and pressure and the strength of the bonds is variable according to its temperature, pressure and bond angle etc.
Let us now look at one of the simplest hydrogen bond, which is one formed in the water. In a water molecule, two hydrogen atoms and one oxygen atom is present. The molecules in the water can bond with up to four other molecules as each oxygen molecule has a lone pair of electrons which can form a hydrogen bond with two hydrogen atoms from other molecules. The great strength and the large number of hydrogen bonds in the water lead to the high boiling point of water. A lot of energy is needed to break the bonds. Water is unique. It has oxygen atom which bonds with two lone pairs and two hydrogen atoms. This shows that the total number of bonds in a water molecule can go up to four. With more bonds, more energy is needed to break them.
Therefore, the high boiling point of water is caused by hydrogen bonds. For example, hydrogen fluoride also has hydrogen bonds. Hydrogen bond basically brings a hydrogen atom and an electronegative atom together. However, hydrogen bonding must not be confused with covalent bonding.
Sunday, July 26, 2009
Entry 1- More about bonding
First Official Post (For Chemistry Journal)
My research question for this chemistry journal will be about the different types of bonding and where they can be found. I will be basically covering on four types, mainly the hydrogen bond, covalent bond, ionic bond and last but not least, the metallic bond. So, what exactly is bonding? It is not the human bonding whereby you develop a close, intrapersonal relationship with your family and friends we are talking about.
Chemical bonding is the process responsible for the attractive interactions between atoms and molecules and gives stability to chemical compounds. The things around us like molecules and crystals are actually having their structures due to the bonds which are holding them together. Molecules are formed because atoms bond together.
Each different bond exerts different amount of energy on the atoms they hold and requires different amount of energy to break them. Covalent and ionic bonds are said to be ‘stronger; as compared to hydrogen bond. Just like magnets, the negatively-charged electrons will attract the positively-charged protons. If an electron is placed in between two nuclei, it will be attracted to both of them. A most stable configuration of nuclei and electrons is one whereby the electrons spent more time in between the nuclei. The nuclei, due to the electrons, will therefore be attracted to each other.
All the bonds can actually be explained by the quantum theory. Simplification rules like octet rule and VSEPR rule help chemists to predict the strength, directionality and polarity of bonds. Electrostatics is used to describe bond polarities and the effects they have on chemical substances. One of the more complicated theories is the valence bond theory.
A little more about the theories. Valence bond theory was formulated in the year, 1927. It states that a chemical bond is formed when two valence electrons hold two nuclei together. Years later, Linus Pauling built on this theory and published an article: On the nature of chemical bond. He had three new rules. 1939, Pauling built on that article and wrote a textbook: On the nature of the chemical bond. That book aids chemists to understand the impact of quantum theory on chemistry. Valence bond theory had been implemented in large computer programs as well.
Below are the research question and an overview of what will be covered in all the entries.
What are the different types of bonding and where they can be found?
Entry 1. More about bonding
Entry 2. Hydrogen bond
Entry 3. Covalent bond
Entry 4. Ionic Bond
Entry 5. Metallic Bonding
Entry 6. Conclusion
As we can all see, bonding can actually be seen in our everyday lives and that their theories are even applied on computer programs. Bonding is what brings atoms or molecules together and forming a new molecule or product. Different bonding can have different amount of strength and some may be easier to break than others. I will be talking about the hydrogen bond in my next entry.
My research question for this chemistry journal will be about the different types of bonding and where they can be found. I will be basically covering on four types, mainly the hydrogen bond, covalent bond, ionic bond and last but not least, the metallic bond. So, what exactly is bonding? It is not the human bonding whereby you develop a close, intrapersonal relationship with your family and friends we are talking about.
Chemical bonding is the process responsible for the attractive interactions between atoms and molecules and gives stability to chemical compounds. The things around us like molecules and crystals are actually having their structures due to the bonds which are holding them together. Molecules are formed because atoms bond together.
Each different bond exerts different amount of energy on the atoms they hold and requires different amount of energy to break them. Covalent and ionic bonds are said to be ‘stronger; as compared to hydrogen bond. Just like magnets, the negatively-charged electrons will attract the positively-charged protons. If an electron is placed in between two nuclei, it will be attracted to both of them. A most stable configuration of nuclei and electrons is one whereby the electrons spent more time in between the nuclei. The nuclei, due to the electrons, will therefore be attracted to each other.
All the bonds can actually be explained by the quantum theory. Simplification rules like octet rule and VSEPR rule help chemists to predict the strength, directionality and polarity of bonds. Electrostatics is used to describe bond polarities and the effects they have on chemical substances. One of the more complicated theories is the valence bond theory.
A little more about the theories. Valence bond theory was formulated in the year, 1927. It states that a chemical bond is formed when two valence electrons hold two nuclei together. Years later, Linus Pauling built on this theory and published an article: On the nature of chemical bond. He had three new rules. 1939, Pauling built on that article and wrote a textbook: On the nature of the chemical bond. That book aids chemists to understand the impact of quantum theory on chemistry. Valence bond theory had been implemented in large computer programs as well.
Below are the research question and an overview of what will be covered in all the entries.
What are the different types of bonding and where they can be found?
Entry 1. More about bonding
Entry 2. Hydrogen bond
Entry 3. Covalent bond
Entry 4. Ionic Bond
Entry 5. Metallic Bonding
Entry 6. Conclusion
As we can all see, bonding can actually be seen in our everyday lives and that their theories are even applied on computer programs. Bonding is what brings atoms or molecules together and forming a new molecule or product. Different bonding can have different amount of strength and some may be easier to break than others. I will be talking about the hydrogen bond in my next entry.
Saturday, July 11, 2009
Conclusion
Seventh Official Post
This will be my final post and it will be a conclusion to summarize everything. So, I will be bringing all the topics being talked about in the previous posts together.
Anaerobic Digestion starts with an initial material. In the first stage, hydrolysis occurs and materials like carbohydrates, fats and proteins are broken down into sugar, fatty acids and amino acids. Next in acidogenesis, acidogenic bacteria will further break down them into carbonic acids, alcohol, hydrogen, carbon dioxide and ammonia.
At actegenesis, acetogens will digest and produce hydrogen, acetic acid and carbon dioxide. Lastly, at methanogens, methane and carbon dioxide will be produced. The 3 principal end-products of Anaerobic Digestion will be:
1. Biogas
2. Digestate
3. Water
Biogas is the main product of the whole digestion. It is something important as it can actually replace fossil fuels. Fossil fuels are non-renewable sources of energy, while biogas is not. Furthermore, fossil fuels are not that environmental-friendly compared to biogas and that they may run out one day too. Biogas can reduce greenhouse effects and act as a source of energy.
Materials which the microorganisms cannot digest will become the digestate. Uses of digetate will differ accordingly to the quality of the initial material put in. Digestate can be used to make products like fiber board. It also acts as fertilizer which helps plants and crops grow.
Water will be produced as well. The water will come from the initial material and the reactions during the processes. Normally, the water must be further treated a little or they will cause eutrophication. However, many industries or companies adopted anaerobic processes to treat wastewater.
So how does Anaerobic Digestion benefit Earth and us?
Earth is now facing a few problems. They are:
Greenhouse Effects→ Global warming
Evolution of humans→ Pollution
Higher energy consumption→ Depleting of natural resources (e.g. fossil fuels)
Anaerobic Digestion can reduce the emission of radiation from materials. It will break down biodegradable products under control. If the products are being digested in landfills by natural anaerobic digesters, the methane and greenhouse gasses will be released into the atmosphere. This leads to the trapping of radiation, heating up the Earth and cause global warming.
Biogas will also produce lesser radiation during combustion as compared to fossil fuels. It is a renewable resource and therefore would not be depleted down the years. It will be a lot more environmental-friendly.
Anaerobic Digestion also provides an alternative way for wastewater to be treated. This way, the dirty and poisoned water will not just be discharged into the oceans, polluting the sea and killing marine animals.
Fertilizer and simple products can be obtained from it. This helps us to save some other resources by recycling. We can obtain biogas and fertilizer etc. from an initial material.
Who would have thought that Anaerobic Digestion could actually help in such a big way? Microorganisms will just digest the initial material and we can get a number of end-products. They are other ways which Anaerobic Digestion can help reduce emission as well. Examples:
1. Reducing vehicles movements
2. Reducing electrical grid transportation losses
Anaerobic Digestion is a useful method of getting rid of biodegradable materials. It can benefit us greatly and help save Earth!
Don’t let Earth be destroyed!!!
This will be my final post and it will be a conclusion to summarize everything. So, I will be bringing all the topics being talked about in the previous posts together.
Anaerobic Digestion starts with an initial material. In the first stage, hydrolysis occurs and materials like carbohydrates, fats and proteins are broken down into sugar, fatty acids and amino acids. Next in acidogenesis, acidogenic bacteria will further break down them into carbonic acids, alcohol, hydrogen, carbon dioxide and ammonia.
At actegenesis, acetogens will digest and produce hydrogen, acetic acid and carbon dioxide. Lastly, at methanogens, methane and carbon dioxide will be produced. The 3 principal end-products of Anaerobic Digestion will be:
1. Biogas
2. Digestate
3. Water
Biogas is the main product of the whole digestion. It is something important as it can actually replace fossil fuels. Fossil fuels are non-renewable sources of energy, while biogas is not. Furthermore, fossil fuels are not that environmental-friendly compared to biogas and that they may run out one day too. Biogas can reduce greenhouse effects and act as a source of energy.
Materials which the microorganisms cannot digest will become the digestate. Uses of digetate will differ accordingly to the quality of the initial material put in. Digestate can be used to make products like fiber board. It also acts as fertilizer which helps plants and crops grow.
Water will be produced as well. The water will come from the initial material and the reactions during the processes. Normally, the water must be further treated a little or they will cause eutrophication. However, many industries or companies adopted anaerobic processes to treat wastewater.
So how does Anaerobic Digestion benefit Earth and us?
Earth is now facing a few problems. They are:
Greenhouse Effects→ Global warming
Evolution of humans→ Pollution
Higher energy consumption→ Depleting of natural resources (e.g. fossil fuels)
Anaerobic Digestion can reduce the emission of radiation from materials. It will break down biodegradable products under control. If the products are being digested in landfills by natural anaerobic digesters, the methane and greenhouse gasses will be released into the atmosphere. This leads to the trapping of radiation, heating up the Earth and cause global warming.
Biogas will also produce lesser radiation during combustion as compared to fossil fuels. It is a renewable resource and therefore would not be depleted down the years. It will be a lot more environmental-friendly.
Anaerobic Digestion also provides an alternative way for wastewater to be treated. This way, the dirty and poisoned water will not just be discharged into the oceans, polluting the sea and killing marine animals.
Fertilizer and simple products can be obtained from it. This helps us to save some other resources by recycling. We can obtain biogas and fertilizer etc. from an initial material.
Who would have thought that Anaerobic Digestion could actually help in such a big way? Microorganisms will just digest the initial material and we can get a number of end-products. They are other ways which Anaerobic Digestion can help reduce emission as well. Examples:
1. Reducing vehicles movements
2. Reducing electrical grid transportation losses
Anaerobic Digestion is a useful method of getting rid of biodegradable materials. It can benefit us greatly and help save Earth!
Don’t let Earth be destroyed!!!
Friday, July 10, 2009
Digestate, a fertilizer
Sixth Official Post
The last product which Anaerobic Digestion produces is the digestate. The microbes cannot feed on everything and the solid remnant of the initial waste material will be called the digestate. It can be fibrous or liquor.
Acidogenic digestate is a material which consists mainly of lignin and cellulose. Low grade building products like fibreboard can be made from it.
Methanogenic digestate is rich in nutrients making it suitable to be used as a fertilizer. However, if the quality of the initial material is low, the levels of potentially toxic elements (PTEs) will be higher. This will make it not suitable to be a fertilizer and the use of it will be dependent on its levels of PTEs.
Lignins which anaerobic microorganisms cannot break down will be present in the digestate. Furthermore, ammonia which will disrupt plant’s growth will be present as well. Aerobic microorganisms will then be introduced to break down ammonia into nitrates, which increase the fertility of the material. Then, it will improve the quality of soil more efficiently.
Anaerobic Digestion provides an alternative for fertilizer. Fertilizers are extremely important in the growing of plants and crops. It can be used to improve the health and productivity of crops. In some countries where a lot of their soil is infertile, they can use fertilizer to be able to grow crops there. Instead of producing fertilizer industrially, Anaerobic Digestion can produce fertilizer while producing biogas. Wouldn’t that be nice?
The last product which Anaerobic Digestion produces is the digestate. The microbes cannot feed on everything and the solid remnant of the initial waste material will be called the digestate. It can be fibrous or liquor.
Acidogenic digestate is a material which consists mainly of lignin and cellulose. Low grade building products like fibreboard can be made from it.
Methanogenic digestate is rich in nutrients making it suitable to be used as a fertilizer. However, if the quality of the initial material is low, the levels of potentially toxic elements (PTEs) will be higher. This will make it not suitable to be a fertilizer and the use of it will be dependent on its levels of PTEs.
Lignins which anaerobic microorganisms cannot break down will be present in the digestate. Furthermore, ammonia which will disrupt plant’s growth will be present as well. Aerobic microorganisms will then be introduced to break down ammonia into nitrates, which increase the fertility of the material. Then, it will improve the quality of soil more efficiently.
Anaerobic Digestion provides an alternative for fertilizer. Fertilizers are extremely important in the growing of plants and crops. It can be used to improve the health and productivity of crops. In some countries where a lot of their soil is infertile, they can use fertilizer to be able to grow crops there. Instead of producing fertilizer industrially, Anaerobic Digestion can produce fertilizer while producing biogas. Wouldn’t that be nice?
Biogas- Renewable source of energy
Fifth Official Post
In the fourth post, I will be talking about the main product produced by Anaerobic Digestion. It is something which is very important to all of us- biogas. Biogas can replace the depleting fossil fuels and supply us with energy as well.
The biogas mainly consists of methane and carbon dioxide along with a small amount of hydrogen. Biogas is more environmentally-friendly as compared to fossil fuels as the carbon dioxide produced is not released directly into the atmosphere. This will then not increase the level of carbon dioxide concentrations in the air.
Using a micro turbine or reciprocating engine, biogas can be combusted to from both electricity and heat. Some treatment to refine the gas and it can be used as fuel.
However, volatile siloxanes may be present in biogas and when burned, will be converted to silicon dioxide. The silicon dioxide will then remain in the machine and increase wear and tear. Solutions have been created to solve these problems. In situ treatment can reduce the content of carbon dioxide and increase the methane purity. In some countries, methane in the biogas will be concentrated to allow the gas to serve as fuel for transportation.
What is so special about biogas? Fossil fuels when burned will generate something called nitric acid and will then fall back to Earth in the form of Acid Rain. It also produces radioactive materials like uranium. When fossil fuels are used instead of biogas, the conditions of global warming will worsen. Worldwide, the burning of fossil fuels produce about 21.3 billion tons of carbon dioxide but the trees and plants can only take in around half of it. This will lead to an increase in carbon dioxide level and carbon dioxide is one of the greenhouse gasses.
Biogas will be very important as fossil fuels are running out. If we run out of fossil fuels one day, at least we can still use biogas as fossil fuels are non-renewable while biogas is a renewable source of energy. However, it will still not be enough to supply the entire world. Therefore, there is still a need to conserve our resources even with the presence of renewable resources.
In the fourth post, I will be talking about the main product produced by Anaerobic Digestion. It is something which is very important to all of us- biogas. Biogas can replace the depleting fossil fuels and supply us with energy as well.
The biogas mainly consists of methane and carbon dioxide along with a small amount of hydrogen. Biogas is more environmentally-friendly as compared to fossil fuels as the carbon dioxide produced is not released directly into the atmosphere. This will then not increase the level of carbon dioxide concentrations in the air.
Using a micro turbine or reciprocating engine, biogas can be combusted to from both electricity and heat. Some treatment to refine the gas and it can be used as fuel.
However, volatile siloxanes may be present in biogas and when burned, will be converted to silicon dioxide. The silicon dioxide will then remain in the machine and increase wear and tear. Solutions have been created to solve these problems. In situ treatment can reduce the content of carbon dioxide and increase the methane purity. In some countries, methane in the biogas will be concentrated to allow the gas to serve as fuel for transportation.
What is so special about biogas? Fossil fuels when burned will generate something called nitric acid and will then fall back to Earth in the form of Acid Rain. It also produces radioactive materials like uranium. When fossil fuels are used instead of biogas, the conditions of global warming will worsen. Worldwide, the burning of fossil fuels produce about 21.3 billion tons of carbon dioxide but the trees and plants can only take in around half of it. This will lead to an increase in carbon dioxide level and carbon dioxide is one of the greenhouse gasses.
Biogas will be very important as fossil fuels are running out. If we run out of fossil fuels one day, at least we can still use biogas as fossil fuels are non-renewable while biogas is a renewable source of energy. However, it will still not be enough to supply the entire world. Therefore, there is still a need to conserve our resources even with the presence of renewable resources.
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