Education (24)
Education should be a life long pursuit and our range of categories reflects this. Find information about schools, homeschooling, study tools and post-secondary eduaction here. In a series of articles you will learn the truths about homeschooling and find out why it is growing in popularity among parents everywhere. We hope that you will discover interesting articles and facts about all aspects of education in this category.
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Study Tools (1)
The study tools category encompasses all types of study methods including books, ways to use the internet effectively for study, information about language courses and much more. No one can study effectively without good study tools and this category will bring you information on the different types of tools that can help you in your studies and the all best ways to use them.
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Post-Secondary (9)
The post-secondary category covers education of all kinds undertaken after secondary school. Not only information about college or university education, but vocational training, on-line courses, re-training for a second career, nursing programs and much more. Find all the information you need in our post-secondary education category.
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Homeschooling (6)
Growing numbers of parents are opting to homeschool their children for a variety of reasons. Perhaps they are unsatisfied with the schooling in their area and feel they can do a much better job or would like a more direct input into their children's education. In this category will help to educate our readers on all aspects of this increasingly popular method of educating our children.
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Our schools category covers a wide range of topics from pre-schools up to secondary schools. Subjects that you might find here include teaching and reading strategies and how to deal with bullying. Parent teachers associations and school governance. Any subjects related to schools may be found in this category.
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General (4)
In the general education category you can find articles that don't fit into the other categories. Articles about science and languages and information on all general aspects of education. Education is a wide subject and our articles in this category cover many interesting subjects.
View items...An Insider Look at the Pell Grant
Written by Jan StevensThe Pell Grant program is the largest federal educational grant program in existence today, and while most students have at least heard of its availability, a vast proportion don’t have a clear idea of how to become eligible, how to apply, and what they can expect to receive in terms of aid if they do eventually become eligible. The good news is that the Pell Grant can be obtained with relative ease by any student who demonstrates what the Department of Education considers to be an “exceptional” financial need. This is measured primarily by the EFC, or expected family contribution, and is supposed to act as an indicator of a family’s ability to contribute money towards their child’s college education.
To qualify students must have an EFC that falls below 5,273 for the 2010-11 school year, as this threshold was increased from 4,617 in 2009-10 as a result of the passing of the Student Aid and Fiscal Responsibility Act, or SAFRA. EFC is calculated after the FAFSA has been completed and certain information has been inserted into a predefined formula that pays reference to certain factors. These include both the student’s and parent’s income, the size of the household, and the number of family members who are attending postsecondary institutions. Other Pell Grant eligibility requirements that students should be aware of include the fact that they should be enrolled as an undergraduate student, and that they should not be serving jail time in a federal or state penal institution. Students who may be enrolled in certain graduate or professional programs may be able to qualify, although most Pell Grants are given to students who have not received their first bachelor’s degree.
Applying for the Pell Grant is no different than applying for other forms of federal student aid such as federal Stafford Loans, and the Perkins Loan, as the FAFSA is the official Pell Grant application that students should complete in order to become eligible. Completing the FAFSA can be done online, or via its written counterpart. The online FAFSA can be completed at the website fafsa.ed.gov, while a written copy of the application can be obtained by calling the phone number 1-800-4-FED-AID. It is important to note that the earlier you can submit the FAFSA the better, as most financial aid is allocated on a first-come, first-serve basis. The earliest you can go ahead and submit the FAFSA is January first, and the latest you can submit one is June thirtieth. The maximum Pell Grant amount is now set at 5,550 dollars for the 2010-11 award year, although the vast majority of college students only receive about fifty percent of this maximum amount. Contact your school’s financial aid department if you need more Pell Grant information that may cater to your own particular circumstances, and credentials.
Identifying the 2010 Pell Grant Amount
Written by Randy CannStudents considering applying for a Pell Grant during the 2010-11 school year should first identify what the maximum available award amount is for this particular academic term. The Student Aid and Fiscal Responsibility Act, or SAFRA has increased this maximum award amount to 5,550 dollars for all students who are attending class on a full time basis, a two hundred dollar increase from the previous year. To become eligible for this maximum award amount students must demonstrate an exceptional financial need, which is primarily determined via the expected family contribution, or EFC.
Students having an EFC value below 5,273 will be able to qualify for the Pell Grant, although the actual award amount they receive will vary in reference to their level of need, cost of attendance, and enrollment status. Most students end up receiving about half of the full award amount, although students that come from families who aren’t able to contribute any capital towards their education related expenses will almost always end up with an EFC of zero, and thus become eligible for the full amount. Students should also be aware that the maximum Pell Grant amount will increase according the Consumer Price Index plus one percent beginning in 2013-14. This was done to keep the Pell Grant in line with the rate of inflation, although it remains to be seen whether or not this modification will truly have an effect.
Overall the Pell Grant can provide students with a substantial amount of funding to utilize towards their higher education, and when used in combination with the assortment of federal student loans that are available, students who demonstrate a very high financial need should have no problem getting a large proportion of their tuition paid off via federal student aid. The current administration plans on expanding the overall reach of not only the Pell Grant program, but other federal student aid programs as well over the next few years or so. It remains to be seen what kind of effect this will have on a student’s ability to get the financial aid they need to pay for school, although most experts agree that it should only have a positive effect over the long-term. If you are interested in applying for a Pell Grant, or for any other form of federal student aid, you need to complete the FAFSA. The FAFSA is the government’s universal application for federal educational assistance, and the deadline for submitting one is set at June 30.
Many people who are looking to go back to school are looking for ways to get a Pell Grant and do not know how to, as they also do not know what a Pell Grant is exactly. Establishing your Pell Grant eligibility takes certain information and requires certain things to be filled out by the person who is going to be attending school. If you are one of the many students looking to qualify for a Pell Grant, keep reading below to get information on how to do just that.
A Pell Grant is money that is given to students each year from the United States government that never has to be repaid. You must be enrolled in either a college level course or graduate school courses. Many students are having a lot of trouble paying their tuition costs as the costs continue to go up, and the good news is that with new Pell Grant changes for 2010, students are going to be able to get even more aid by way of the Pell Grant.
In order to be able to qualify for a Pell Grant, you must fill out a FAFSA form that is required by the United States government each year. The forms are very easy to fill out and can take just a couple of minutes to do them. You can either fill the forms out online or you can enlist the help of the financial aid administer at your school of choice. If you prefer to do the form yourself you can call the Department of Education and they will mail the form to you.
When you get ready to fill out the FAFSA form in order to gain the appropriate Pell Grant eligibility, you must have your financial information handy. You will need your information as well the information of your parents should you still live at home with them. You will also need to have handy the prior years tax form if you are on your own filling on out for yourself. You will also need to make sure to have the schools information handy as you must submit it also. In order to get a Pell Grant, you must be a US citizen and have never been convicted of a felony.
In order to get the greatest amount of a Pell Grant aid, you must demonstrate a significant financial need. The lower income you have, the more you can get via the Pell Grant. Pell Grants are something that can help a person afford school more easily. Make sure to fill out all the appropriate information and that it is correct so you can take advantage of getting a Pell Grant for your education.
Help with Dissertation Examples
Written by Strathy
When looking for dissertation examples, you must think closely about the topic that you are choosing. You will write a better thesis if you are familiar with the topic and have a strong opinion about it. If you can honestly take a stand at a particular viewpoint you will do better in the final thesis defense (viva voce). If you find the topic interesting, it will help motivate you to study the subject matter and write about it from your own viewpoint. You must be prepared to spend a lot of time researching and proving your dissertation statement. You will need to know all the ins and outs of the topic in order to answer questions in your dissertation defense.
Here we will discuss a variety of subjects that would make good dissertation examples to choose from. First you will need to decide on a general topic area of interest. It is a good idea to choose a subject matter that is relevant to your course of study and degrees, whether you be in the math and sciences area or the arts and humanities area. Here are some examples:
Geology, entomology, biology, archeology, mathematics, sociology, IT, technology, communications, eco-tourism, fine art, music, theatre, literature, languages, writing, law, history, commerce, economics, etc.
Once you decide on a main topic area, you will then need to narrow it down to get your final thesis idea. You will need to dig deeper into the area you are interested in to find an actual thesis topic. Brainstorming with someone else will help you think of ideas as well. It is important to narrow your topic down so that it is not too broad an area or you will appear unfocused. Here are some questions to ask yourself when trying to think of dissertation examples.
- how familiar am I with the subject matter?
- do I have a strong viewpoint on the subject?
- is it something I can prove or disprove in my thesis?
- is there material available for referencing?
- can I dig up research material to support my thesis?
- is it a unique viewpoint? Has it been done before?
Perhaps there is something in your course of study that has always nagged at you. Something that you wished you could have delved into a little deeper. Or, maybe it's something that not a lot has been published on that you know people would be interested in hearing. You may have been taught to think a certain way about a particular situation in history, for example, but maybe you know of facts that point the thought in a different direction.
Carefully consider the points discussed above and they should be of help to you when looking for dissertation examples or thinking up thesis topics to do for your graduate work.
The Chemistry of Polymer Synthesis
Written by janet
Polymers can be natural or synthetic. Some examples of natural polymers include starch, cotton and rubber but in this article I'm going to talk about synthetic polymers such as nylon, polyethene or perspex. The building blocks of polymers are called monomers which are connected together into long chains. Synthetic polymers can consist of chains of thousands or even millions of monomer units. We'll look at the types of monomers and how they are bonded together to make polymers of various kinds.
Synthetic polymers can be divided into two types, addition polymers and condensation polymers. They are formed from different types of monomers and with different bonds between them.
Addition Polymers
Addition polymers are always made with a group of organic compounds called alkenes. These all contain a double bond between two carbon atoms. Double bonds are more reactive than single bonds and can be induced to react together, given the right conditions which usually include the use of a catalyst, increased temperature and sometimes an increased pressure. Alkenes bond together in an addition reaction and form addition polymers.
An alkene - ethene
All bonds contain two electrons and the ethene molecule has a double bond between two carbon atoms. One of these bonds is more reactive than the other one and this bond breaks during the polymerisation process. The two electrons in the bond split up and end up on each of the carbon atoms. Now the electrons on adjacent ethene molecules can join together to form a bond between the two carbon atoms on different molecules thus joining the two molecules together with a single covalent bond. The electrons on the other carbon atoms can do the same thing and join up with other ethene molecules to start to form a chain. This process can continue until a huge chain is formed.
Formation of Polyethene
Formation of radicals
Naming of Addition Polymers
Polymers are named for the alkene monomer from which they are formed so, for instance a polymer made from the alkene called ethene forms the polymer polyethene (usually called more simply polythene). Other examples include polyvinylchloride (PVC) made from chloroethene which used to be called vinyl chloride, polystyrene and polytetrafluoroethylene (PTFE or Teflon).
Condensation Polymers
In this type of polymerisation, monomers are bonded together with the elimination of a molecule of water, hence the name condensation polymer. The monomers used in condensation polymerisation can be di-alcohols (containing two -OH groups), di-carboxylic acids (containing two -COOH groups) or di-amines (containing two NH2 groups). When a polymer is made from a di-alcohol and a di-carboxylic acid an ester link is formed and the resulting polymer is a polyester as illustrated below.
Formation of condensation polymers
When a polymer is formed between a di-carboxylic acid and a di-amine a polyamide is formed. An example of a di-amide is nylon. The monomers used in this type of polymerisation must have reactive groups at both ends to allow chains to be formed.
Once the polymers have formed, further treatment is needed to produce plastics. Dyes, stabilisers, fillers and pigments are added to produce finished products. Polymers have different properties depending on the monomers used in their production and are used in various ways. Polyethene for example is used for plastic bags, mixing bowls etc. PVC is used for water pipes, floor tiles, waterproof articles and insulating materials. Nylon is used for textiles, ropes and carpets.
Most organic compounds can be composted and the resulting material used to great benefit in your garden. Organic compounds refers to anything that comes from animals and plants and usually has a high percentage of carbon and hydrogen, plus trace amounts of other elements such as sulfur, oxygen etc.
The aim of a compost pile is to make an environment ideal for the micro-organisms that are the main decomposers of the organic material. In addition ants, worms and snails also play a part. All organic waste will decompose over time but in a compost pile you are providing the ideal conditions for these organisms to thrive, thus accelerating the process. Organic waste will contain compounds such as proteins, sugars, carbohydrates, starches, cellulose etc which are broken down at different rates. Carbohydrates are easily broken down to their constituent sugars while plant remains containing cellulose take longer.
Getting the carbon to nitrogen ratio right
For optimal conditions that encourage microbial growth it is important that the ratio of carbon to nitrogen in the compost pile is correct. The ideal ratio is around thirty parts carbon to one part nitrogen. Carbon is the energy source for the growth of the microbes, nitrogen is needed in smaller amounts for growth as it is a crucial element in enzymes, proteins and DNA. However, if you supply too much nitrogen it will be turned into ammonia (NH3) which will make your compost pile smell! Too little nitrogen however will prevent the microbes growing at the fastest rate and slows down the decomposition.
So how do you ensure the ratio is correct? The ratio of 'green' to 'brown' compost materials is the best way to do this. Green materials are the fruit and vegetables scraps from the kitchen, coffee grounds, grass clippings etc which will be high in nitrogen. They also contain the bacteria that you need to begin the decomposition and to supply energy in the form of heat. Brown materials are high in carbon and are the woody materials such as paper, cardboard, dried autumn leaves and sawdust. You need to make the ratio of these materials 30:1 for the best conditions inside your compost pile. If you have too many autumn leaves make a seperate pile for composting into leaf mold. Don't make the mistake of only adding green waste to your bin or you'll end up with a rotting mess full of fruit flies with a horrible smell!
Composting is an aerobic process
Aerobic means 'with oxygen'. The microbes in the compost pile use oxygen when they process the material, using the carbon for both energy and as building material for their cells. They also use the nitrogen to make proteins and DNA but need much more carbon which is why you need only a small proportion of nitrogen in your bin. Other trace materials need by the organisms to grow include phosphorus, sulphur and a variety of metals such as iron, copper, and calcium in trace amounts. In order to encourage aerobic decomposition, oxygen needs to be supplied. This can be accomplished by agitating the pile with a fork or spade regularly. In aerobic respiration a lot of energy in the form of heat is produced.
The chemical equation for aerobic respiration follows:
If the supply of oxygen is inadequate anaerobic respiration (without oxygen) will result in the production of methane and volatile organic acids, ammonia and other compounds. Sulfur containing compounds such as hydrogen sulfide are also released. Contrary to popular belief methane has no smell, it's the other compounds that are also produced by the methanogens (the bacteria active in anaerobic decompostion) that give a badly aerated compost heap it's smell.
The chemical equation for anaerobic respiration follows:
Why does a compost pile become hot?
The microbes present in the green, moist materials added to the compost pile respire aerobically using up oxygen and releasing carbon dioxide. They also release a great deal of enegy in the form of heat. A compost pile can reach temperatures as high as 150F in a few days given the right conditions. Oxygen is needed to sustain this temperature which is why it is important to agitate the pile regularly or the aerobic microbes will die off and anearobic microbes take their place.
The pH of the compost pile
The pH level in the compost needs to be between about 5 and 8. In a new compost pile the digestion of the organic matter often produces some organic acids which lower the pH. This is not a bad thing however as this encourages fungi to grow which then digest the cellulose in plant materials. In a properly aerated pile the organic acids are themselves broken down. However if you don't aerate the pile adequately the pH can drop below about 5 because the organic acids begin to accumulate and this starts to restrict the activity of the aerobic microbes.
Conclusion
Chemistry in everyday life is fun to find out about! Now you know what is going on in your compost pile, why it gets hot and why it smells if you don't get it right! If you're eager to get started on your own compost pile see How To Make A Compost Heap In Your Garden
Making the decision to homeschool your children, should not be taken lightly. I know, because I am the parent of a homeschooled child. We made the decision to homeschool our children for a variety of reasons. Here I will delve into some of these reasons. Perhaps this will help you in any decision you may have about homeschooling your own child.
Safety
Where we live, there is a concern over the safety of children in our local schools. We are often hearing of school lock downs in the news for a variety of reasons. Crimes such as stabbings, drugs being found in school lockers and bullying are just a few of the reasons why we do not feel comfortable sending our young child out into a school environment where he cannot be protected. The student to teacher ratio is just not conducive to keeping all the children safe, either while in school or in the playground. Not only that, but this ratio makes it more difficult for learning in a classroom environment, which we will discuss in our next point.
Accelerated Learning
As stated in the previous paragraph, it is difficult for a child to learn and be educated when they are one of approximately 30 students in a classroom assigned to 1 teacher. It is particularly challenging for the teacher to give one-on-one attention to each student, assess their needs, and provide them with the tools necessary for each one to excel. Students who are gifted are not challenged and waiting around for the other students to catch up. Students who are slow, are not getting the attention they require to catch up to the other students.
Providing a homeschool environment for the student allows the child to learn at their own pace. It does not force them to go on to the next section if they have not fully understood the previous one. One-on-one attention by a parent/teacher allows the student to ask all the questions he or she feels are necessary in order to understand and learn. In addition, the waiting time of a teacher working with 29 other students is not there and so the homeschooled student has the opportunity to excel at a more accelerated pace. You will often find homeschooled students are further ahead in their learning than their regular schooled peers.
Learning Environment
The learning environment of a homeschool is such that the child feels safe and free to learn at their own pace. The location being flexible is also a great benefit. If it's a nice sunny and warm day, the parent can move learning time to out in the back yard. Or, if the family is on a camping trip, school goes along with them. Being a homeschooled family allows you to be flexible in the location of study and as such frees up the family to travel and spend time away from their home. All while learning. You will often find homeschooled children in families that are on the road on an extended vacation. These children will most likely have education surrounding their current locale included in their schooling. Breaking up the monotony makes things more interesting. If a child is interested, they will learn and remember.
Course of Study Control
Having control over the course of study of my homeschooled child is very important. We are free to choose the cirriculum that we wish to use. We can mix and match different areas and customize it to our child's specific needs. Having the ability to teach our families' values to our children, and not someone else's, is important to us as well.
More Family Time
Homeschooling allows us to have more family time together. Our children are always with us and we take them pretty much everywhere. They have the benefit of knowing that they are in a secure and safe place. Spending time together as a family gives a security to children. One that they will value and learn from as they grow older and go out into the work force.
I could probably go into other reasons why we homeschool our children, but for now I thought I'd give you a little insight into my perspective as a mother who homeschools. If you are thinking of homeschooling your children, maybe some of the reasons I've discussed above will help you make your decision.
The chemistry behind fireworks started over 2000 years ago when, according to legend, the firecracker was invented when a Chinese cook mixed up charcoal, sulphur and saltpeter. He discovered that it would explode if packed into a bamboo tube and set alight. In the 9th century the Chinese invented gunpowder and produced fireworks for important events such as the Moon Festival and New Year using a combination of potassium nitrate (also called saltpeter), sulphur and charcoal.
Each of these chemicals burns in a different way. Charcoal burns slowly, potassium nitrate quickly and sulfur crackles and pops as it burns. Using different proportions of these chemicals produced various kinds of displays. They also invented rockets by placing gunpowder in a roll of paper and igniting it at one end.
Chemistry of fireworks
To start off the reaction energy must be supplied by lighting the fuse. Potassium nitrate acts as an oxidiser by providing oxygen for the charcoal or fuel to burn, sulphur helps to keep the reaction stable. Without the oxidiser the reaction would be too slow, the oxygen provided by the potassium nitrate speeds up the reaction. The three ingredients produce potassium sulphide, carbon dioxide and nitrogen which expand with the heat and provide the propelling force. In addition the reactions are exothermic, that is they produce heat, which contributes to the rate at which the gases expand and increases the explosive power of the reaction.
Fireworks were originally only able to produce yellow or white light which was emitted by heating up the gunpowder mixture. The effect can be varied to produce more glitter by increasing the amount of sulphur or a quick flash by adding more potassium nitrate. When white or yellow light is emitted in this way it is called incandescence. As a substance is heated it glows first with a red light (~480C) through bright red (~730C) to bright orange (~930C) and yellow (~1100C) then white at over 1400C. Until the late 18th century these were all the colours that could be produced in fireworks. Chlorates were produced industrially in the 19th century and allowed reds and greens to be produced in firework displays. It was only in the 20th century that purples and blues could be produced.
How does the oxidiser work?
When heated potassium nitrate releases oxygen and nitrogen but not all of the oxygen is released. Some remains bound to potassium ions.
When chlorates were manufactured industrially they began to be used in fireworks as they are better oxidisers than the nitrates. They release all their oxygen on heating so they are better oxidisers and can produce higher temperatures in the firework which allows more intense colours to be seen and a faster explosion.
However chlorates are fairly unstable so need very special care and today perchlorates are used as they are more stable but, as they also release all their oxygen, are also good oxidisers.
The chemistry of fireworks colors
Today we have fireworks that emit red, blue, green, yellow and lavender light so how is this possible? The answer lies in the way metals emit light as they burn.
Some metals and the colour of light they emit
Sodium yellow
Barium green
Strontium red
Copper blue
Potassium lavender
Caesium violet
Magnesium brilliant white
You may have done flame tests at school to discover the identity of a metal by placing it in a flame and noting the characteristic colour that is emitted.
How do metals emit coloured light?
To find out what happens when we burn a metal we need to know something about the atoms of the metal. All atoms have a nucleus containing protons and neutrons (except hydrogen which is the lightest atom and doesn't have any neutrons). Electrons are in orbitals at various distances from the nucleus. The electrons will always occupy the lowest energy level possible, which are the ones closest to the nucleus.
When the electrons absorb energy, e.g. if they are heated, the energy allows them to jump to a higher energy level further away from the nucleus. Once in the higher energy levels they are unstable and will fall back to a lower energy level. When they do so they emit radiation in the form of light. The wavelength of the radiation emitted depends on the energy difference between the energy levels and is different for different metal atoms and for different energy levels within the same metal, so the colour of the light you see emitted will vary with the metal.
Some metals that burn brightly such as magnesium and titanium are used for both the bright light they emit and to increase the temperature of the burning compounds.
So next time you watch a firework display not only will you marvel at the wonderful colours and sounds but you will know more about how they are produced and the fascinating chemistry of fireworks!
We all like to eat meat that is tender and succulent rather than tough and stringy so what is the best way to tenderize meat? How tender meat is naturally depends on a number of factors including how the meat is treated after the animal is slaughtered, the type of meat and the age of the animal.
Meat has a high proportion of protein in the form of connective tissue, called collagen, which needs to be broken down before it is tender enough to eat. Collagen makes up around 30% of the protein found in animal tissues and is a major component of skin, cartilage, organs, bones and tendons.
What is collagen?
Collagen is a protein that is made from three intertwined poly-peptide chains. A poly peptide chain is a chain of amino acids bonded together to make a natural polymer. It is a stiff, strong structure that is hard to break down. Muscles that are weight bearing or used often contain larger amounts of collagen than other parts of the animal so legs and rump will be high in collagen. The age of an animal also has a bearing on the amount of collagen present which is why meat from older animals is tougher than that from younger ones.
Collagen
What ways are there to tenderize meat?
Hanging - meat can be hung after the animal is slaughtered. This loosens the muscle fibres.
Grinding and pounding - hitting the meat with a mallet is a popular way to tenderize meat, especially steak. The action of pounding on the meat loosens the muscle fibres by breaking up the connective tissue. Mincing or chopping up meat also has the same effect.
Cooking - cooking meat slowly with moist heat breaks down the collagen. However cooking also hardens the muscle fibres so a balance needs to made between gelatinising the collagen and preventing the muscles fibres from hardening. Moist cooking for around three hours is usually enough to break down the collagen but not long enough to harden muscle fibres. The exception to this is cooking some meats, like steak, that do not have a high collagen content. These types of meats are best cooked quickly with a dry heat as they will become tough if cooked slowly. Some meats can also be tenderized more easily in a pressure cooker. Gelatin is the product when collagen is broken down by heat.
Marinating - meat can be marinated in alcohol and acidic fruits or vinegar to tenderize it. Marinating is also used to add flavour to the meat. Marinating takes time for the ingredients to break down the connective tissue in the meat. Alcohol is effective but acids from vinegar or fruits works even better.
Using enzymes to tenderize meat - some foods contain enzymes that can be used to tenderize meat. Papaya (Paw-paw) contains the enzyme papain and pineapple contains bromelin both of which break down the collagen in meat. As we said earlier collagen is made up of three protein chains and these enzymes can break the bonds between the amino acids in the protein chains.
Individual amino acids in the protein are joined together with a peptide bond (coloured blue in the protein fragment pictured below). It is this bond that these enzymes break, thus fragmenting the protein chains and destroying the collagen structure.
Protein fragment showing peptide bond (in blue)
Conclusion
Chemistry in everyday life is a fascinating subject! Look around you and you can see examples of how chemistry comes into almost everything you do every day. I hope this has sparked an interest in this subject and that you will be eager to learn more.
Image Credits
Collagen by Nevit
papaya by Olegivvitby
Cast Iron Cooking by LarimdaMEMeat
Chemistry in Everday Life - Acids and Bases
Written by janet
Chemistry is going on around us all the time and we meet chemical reactions every time we cook, light a fire or watch a firework display. Today I'm going to talk about acids and bases in everyday life. Fundamental to understanding chemistry is knowing about acids and bases, what they are and what reactions they take part in. Let's start by finding out exactly what an acid and a base is then see where you will come across their reactions every day.
Acids
By definition an acid is a substance that releases hydrogen ions (H+) in water.
Examples of some acids are hydrochloric acid (HCl found in your stomach), nitric acid (HNO3 used in fertilisers) sulphuric acid (H2SO4 used in batteries), phosphoric acid (H3PO4 used in colas). Acids that are present in natural substances include ethanoic acid (or acetic acid CH3COOH present in vinegar), citric acid found in citrus fruits and lactic acid found in milk. All of these acids have a hydrogen atom in their formula which can be released when the acid is in contact with water. So HCl reacts in this way when it comes in contact with water.
Bases
One definition of a base that is often used is that it is a substance that releases hydroxide ions (OH-) in water. Another, and better, definition proposed by Johannes Brønsted and the Thomas Lowry independently in 1923, defined a base as a substance that accepts hydrogen ions. This definition is preferable as it includes ammonia which contains no hydroxide ions but does react with acids in the presence of water to form form a neutral solution.
Examples of bases include sodium hydroxide (caustic soda NaOH) found in some oven and drain cleaners, lime Ca(OH)2 used to make cement, magnesium hydroxide Mg(OH)2 used as an antacid, baking soda (NaHCO3) a raising agent used in cooking and ammonia (NH3) found in some cleaning products.
Note that we said above that an acid releases hydrogen ions (H+) in water. This is important as acids and bases only behave as acids and bases when they are dissolved in water. As an example lets look at HCl. HCl is, in fact, a small molecule that is a gas and does not behave like an acid. Only when it is dissolved in water does it become hydrochloric acid and exhibit the properties of an acid.
The pH Scale
The pH scale is used to show how acidic or basic a substance is. pH 7 is neutral, acids have pH's below 7 and bases above 7. The diagram shows the pH of some common substances.
The pH is found by using the following formula:
pH = -log[H+] note - we use square brackets to denote concentration in mol/l so [H+] reads as the concentration of hydrogen ions.
So an acid with a [H+] of 0.1 mol/L has a pH of 1
Making Your Own pH Indicator
It's easy to make an indicator from red cabbage. An indicator is a substance that changes colour according to the pH of the solution. Red cabbage juice contains the pigment flavin which is red in acidic solutions, purple/blue when neutral and green or yellow when basic. Chop up some red cabbage cover with boiling water for about ten minutes to extract the juice or use a blender with some hot water. Filter the resulting solution with a coffee filter to obtain a clear purple coloured solution. You can then use this to test some of the chemicals we've discussed here. The image above (by Yves.brenner) shows a range of household chemicals. From left to right water (neutral), a strong acid (acidic), vinegar (slightly acidic), ammonia (slightly basic) and sodium hydroxide (basic).
Neutralisation
When the hydrogen (from an acid) and the hydroxide ion (from a base) come together a molecule of water is formed which is neutral. A simple way to remember this is that 'an acid and a base gives a salt and water'.
For example:
If we simplify this to the action of the H+ ions (from the acid) with the OH- ions (from the base) we get the neutralisation equation
Acids and Bases in Everyday Life
Now we know what acids and bases are let's see how we might come across their reactions in everyday life.
Baking Soda
Baking soda (sodium hydrogen carbonate NaHCO3) is slightly basic and is used as a raising agent in cakes, scones and other baked goods. Some recipes for scones include tartaric acid to make the scones rise more. This is because, when an acid reacts with a carbonate or a hydrogen carbonate, carbon dioxide is produced. The carbon dioxide expands as the temperature increases and the scone rises.
The Fizz in Antacids
Some antacids fizz when you add them to water. Citric acid is added to antacids so that it reacts with sodium hydrogen carbonate (NaHCO3) to produce carbon dioxide (as noted above) thus making them more pleasant to drink!
Phosphoric Acid
Many colas include phosphoric acid to provide flavor. It's often used in preference to citric acid which is more expensive. Phosphoric acid is also used to make products for dealing with rust such as gels and liquids. The brown flaky iron oxide is converted to black ferric phosphate which is more solid than iron oxide and provides protection against further rusting.
Phosphoric acid
Acid Rain
Acid rain is polluting many parts of the world and is a result of burning fossil fuels. Although coal and oil are made up mostly of carbon compounds they also contain small amounts of sulphur from the proteins that were present in the original plants. Sulphur, when burned, produces sulphur dioxide which dissolves in water in the clouds to form sulphurous acid. This then reaches the earth in the rain. Another cause of acid rain is the nitrogen oxides released by motor vehicles, resulting in the formation of nitric acid and nitrous acid in the clouds. Acid rain damages plants and buildings and can enter the water courses, damaging aquatic life.
Conclusion
The reactions of acids and bases in everyday life is a fascinating subject and many professional chemists have started out in their chosen careers after being intrigued by the chemical processes going on around them every day. This is only a short introduction so I hope, after reading this, you will be as interested in chemistry as I am and be eager to find out more about this interesting subject .
