To investigate how temperature affects the concentration Essay Example

due to the burette which dripped slowly into the beaker.

Knowing the amount of DCPIP needed to react with the orange juice at room temperature gave me an idea of the amount of vitamin C in the solution compared to the amount in heated solutions of orange juice. The more vitamin C in the solution, the more DCPIP needed to react with it. I heated solutions of orange juice to 41, 51 and 61 degrees centigrade. Then with two repeats for a higher accuracy, I measured the amount of DCPIP needed to make each solution react and turn purply brown.

The real deal (Actual Experiment): As the preliminary results had taken too much time to obtain due to me having to heat each solution one at a time, I decided to make use of the water bath. This meant I could do two repeats at each temperature in the time it would take to just find the amount of DCPIP needed at one temperature. This speeded things up and I kept my method the same as my preliminary. The only difference I made was in using 10 cm3 of orange juice; thereby reducing the amount of DCPIP needed and quickening the time to find the amount of DCPIP needed.

Introduction: The positive effects on a person's health that are brought about by vitamin C have been obvious to the ancient civilisations such as the Egyptians, whose herbal remedies and knowledge about healing far exceeded what we would expect from a civilisation more than 2000 years old. In more recent times in the West, it was James Lind who first realized that vitamin C is a necessary part of

a man's diet, after witnessing the healing effect of c=vitamin C on his men who were suffering from scurvy.

James Lind was the doctor on board the Salisbury over 250 years ago, yet even now the full extent of vitamin C's benefits has not been discovered, despite numerous scientific studies by numerous countries. Spinal Discs A study from Japan concluded that the majority of disc herniations are due to a deficiency of vitamin C. This makes sense, the discs in our spinal column resembling donuts, with a tough, gristle=like exterior and a soft, cushioning interior. A lack of proper amounts of vitamin C will produce a disc with compromised integrity.

This means that the tough exterior will deteriorate in strength. Over time and much wear and tear, this compromised exterior will wear down and a pinhole will result. Moving just the right way will push some of the soft interior material out this pinhole. That is called a disc herniation. If this squished-out material touches a nerve in your spinal column, it causes pain and usually a lot of it. Adequate Vitamin C will toughen up the outside portion of the disc and a herniation is much less likely. Immune System

Vitamin C is required for the proper functioning of our immune systems. It is involved in the production of white blood cells, T-cells and macrophages. Without Vitamin C in sufficient quantities, our own body's best defence against disease is left without ammunition. This has a distinct bearing on how much Vitamin C to take. A sickness such as a cold or virus can be described as being like a brush fire. This leaves destruction in its path,

just as an infection wrecks havoc to our own internal ecology.

If the sickness is the fire, then our immune systems are the fire department and Vitamin C is the water. Taking this analogy a little further, the fire department may use chemical fire retardents, which are to some extent analogous to medicine. Now these chemicals are sometimes warranted, but also they will have some consequences to the environment or ecology. This is similar to nutrition and medicine. Nutrition is the natural bolstering of our own systems. Medicine, on the contrary, is foreign and needs to be used with corresponding care.

Due to the strong relationship between C and our immune systems, it is not surprising that viral and bacterial infections can be dealt with by our own systems when adequate C is present. Ascorbic acid is toxic to viruses, bacteria, and many types of cultured cells, because of its prooxidant activity. It is particularly toxic to malignant tumour cells but much less toxic to non-malignant normal cells, thus its therapeutic use in cancer. Collagen Bleeding gums, easy bruising and an affinity towards bone fractures are all symptoms of scurvy.

All these symptoms come about as a result of the requirement for Vitamin C in the development of the ground substance between our cells. It is this ground substance, primarily collagen, is the cement that gives our tissues form and substance. Collagens are principal components of tendons, ligaments, skin, bone, teeth, cartilage, heart valves, intervertebral discs, cornea, eye lens, as well as the ground substance between cells. Some collagen will form in the absence of ascorbic acid, but the fibers are abnormal, resulting in skin lesions and blood

vessel fragility, characteristics of scurvy.

A person who is dying of scurvy stops making this substance, and his body falls apart -- his joints fail, because he can no longer keep the cartilage and tendons strong, his blood vessels break open, his gums ulcerate and his teeth fall out, his immune system deteriorates, and he dies. Collagen is a protein, one of the thousands of different kinds of proteins in the human body. Most proteins occur only in small amounts. This is because the various enzymes are so powerful in their ability to trigger specific chemical reactions to take place rapidly that only a gram or two or even a few milligrams may be needed in the body.

There are a few exceptions. There is a great amount of hemoglobin in red blood cells. There is even more collagen in the skin, bones, teeth, blood vessels, eye, heart, and, in fact, pretty much in all parts of the body. Collagens are strong white fibers, stronger than steel wire of the same weight. As yellow elastic systems (called elastin), often together with macro polysaccharides, they form the connective tissue that holds our bodies together. Like other proteins, collagen consists of polypeptide chains; the long chains of this fibrous molecule contain about one thousand amino-acid residues that totals around 1600 atoms.

It differs from most other proteins in being largely composed of but two amino acids, glycine and hydroxyproline. Collagen is a kind of super molecule in its three-dimensional architecture. The polypeptide chains of the two amino acids are coiled in a left-handed helix and alternate with one another, punctuated by the presence of certain other amino acids. 3 of

these helical strands are twisted around on another, similar to strands of a rope, in a right-handed super helix, to compose the complete molecule.

It appears that vitamin C is involved at every step in the manufacture of collagen. First, a three dimensional stranded structure is assembled, the amino acids glycine and proline its main components, not yet collagen but its precursor, procollagen. A recent study shows that vitamin C has to have an important role in its creation. Prolonged exposure of cultures of human connective-tissue cells to ascorbate stimulate an 6 times larger increase in the production of collagen with no increase in the rate of synthesis of other proteins.

Since the production of procollagen must go before the production of collagen, vitamin C must have a role in this step -- the formation of the polypeptide chains of procollagen -- along with its better-understood role in the transformation of procollagen to collagen. The transformation involves a reaction that replaces a hydroxyl group, OH, for a hydrogen atom, H, in the proline residues at certain points in the polypeptide chains, converting those residues to hydroxyproline. It is this hydroxylation reaction secures the chains in the triple helix of collagen.

The residues of the amino acid lysine are transformed to hydroxyl sine, before hydroxylation is needed to allow the cross-linking of the triple helixes into the fibers and networks of the tissues. Two different enzymes are the catalysts for these hydroxylation reactions: prolyl-4-hydroxylase and lysyl-hydroxylase. Vitamin C also serves with them in bringing about these reactions. It has recently been shown that, in this service, one molecule of vitamin C is destroyed for each H replaced by OH.

It

should now be obvious to anyone that vitamin C is highly beneficial to our health, yet not enough studies have been carried out to determine all the ways it can help our bodies and minds. Vitamin C improves our health as it does with other mammals, yet unlike them, we get our vitamin C from the foods we eat. While mammals make the necessary amount of vitamin C in their bodies, we have to obtain ours through nutrition which explains why it is so important to know the answers to 3 questions:

1) What exactly are the benefits of vitamin C? ) How much vitamin C do we need every day to maintain good health? 3) How much vitamin C is in the foods we eat? While I cannot answer ANY of these questions fully in this experiment alone, I can try and find out the amount of vitamin C in a single product, such as orange juice. Conclusion: The results show that the higher the temperature, the lower the amount of DCPIP was needed to react completely with the orange juice. On the graph of temperature versus amount of DCPIP used, I got a curve.

This indicates that while the amount of DCPIP decreases as the temperature increases, at some point the amount of DCPIP remains constant. I am taking this to mean that without any really dramatic changes in heat, no more vitamin C molecules can be broken down. In considering this information, I would agree with it and I believe my results to be correct, as they appear to make sense. The more the number of vitamin C molecules decreases, the more activation energy

is needed to break the bonds holding the molecules together, as a small number of molecules has a smaller surface area than a large number of molecules.

Therefore while the first few vitamin C molecules don't require a large amount of heat energy to break down, the last few, with a small surface area and low concentration, would take a huge amount of heat energy to break down which we did not provide. This conclusion supports my prediction, in that I stated I expected that the greater the increase in temperature of the orange juice the less DCPIP needed to react with the orange juice. However I did not expect a curve on the graph temperature versus amount of DCPIP used.

This is because often the juice was chilled before we used it. This water could have had an effect on our results by diluting the orange juice. This would lower the concentration of the orange juice and the the vitamin C. By lowering the concentration, the vitamin C molecules take longer to react with the DCPIP, which perhaps meant I used too much DCPIP without realising. Had I had time I would simply have bought the orange juice the day before and kept it out of the fridge.

I believe my results were fairly accurate but I would hesitate to say faultless. With a short time to collect my results and the preliminary results, I believe I would have obtained more accurate results if I had had more time. I would like to have used the ascorbic acid and measured the amount of DCPIP it needed to turn purply-brown. Then I would have compared it to one

of my samples and found out the exact concentration of each sample, instead of making do with finding out the amount of DCPIP needed. I plan to do this if given further time.