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# GCSE: Patterns of Behaviour

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1. ## How does changing the concentration of hydrochloric acid affect its rate of reaction with magnesium?

The reaction has a lower temperature, which means that there is lower activation energy. There are an increased number of successful collisions, therefore an increase in the rate of reaction. In this experiment, I am going to investigate the effect of concentration on the rate of reaction between two chemical reactants. Preliminary experiment Before doing the actual experiment, I did a preliminary study to help me find a suitable range for the concentrations and how to control the temperature for the main experiment.

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2. ## Does concentration affect the rate of reaction between magnesium strips and hydrochloric acid?

The more particles there are dissolved, the more concentrated the solution. If the acid solution is more concentrated, then there are more particles of hydrochloric acid in a given volume to collide with the magnesium, which leads to more successful and effective collisions between the hydrochloric acid and magnesium, therefore giving a faster rate of reaction. When magnesium reacts with hydrochloric acid, magnesium chloride and hydrogen gas is formed. The equation for this reaction is: Magnesium+ hydrochloric acid = magnesium chloride + hydrogen Mg 2HCL MgCl2 H2 Prediction I predict using my scientific knowledge that if I increase the hydrochloric acid concentration, I will be increasing the number of acid particles

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3. ## Investigation On The Enzyme Trypsin

After denaturisation, the enzyme becomes useless as no more substrates can become further digested by them. Since there was ample trypsin for our use, and because trypsin begins to denature by 50�C (the temperature of the water bath I was using), I used a fresh batch of trypsin for each experiment I performed. Before I started, it was important for me to decide what factor I was going to set as my independent variable and what I was going to setting as my dependant variable. There were several possibilities. Since speeding up the reaction was obviously one option, I could have changed either the heat of the reaction or the concentration of trypsin.

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4. ## The effect of aspirin on the action of bovine liver catalase

This is because aspirin also has effects on other bodily functions including: o Stimulation of the respiratory centre o Inhibition of Krebs cycle (respiration) o Inhibition of amino acid metabolism Aspirin affects all tissues (as it affects metabolism), especially the stomach where it reaches high concentrations, but also in particular the liver, kidneys and lungs. Heavy drinkers who take aspirin have been found to have an increased chance of liver disease. Another more rare, but more serious illness, Reye's syndrome, has also been associated with aspirin.

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5. ## Science Coursework

If the temperature has been decreased then the reaction is slower. When the temperature increases the particles have more kinetic energy and therefore there will be more successful collisions betweens the reactions. As a result the rate of reaction increased. 2. Concentration If the concentration is higher then the reaction is quicker. Therefore if the concentration of sodium Thiosulphate was higher then the reaction is quicker. This is because when the concentration is higher there are more particles of solute and the greater the chances of successful collisions. The more change of collisions between reactants the faster the rate of reaction will be.

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6. ## INVESTIGATING THE RATE OF REACTION BETWEEN MARBLE CHIPS AND HYDROCHLORIC ACID

At a higher concentration collisions are again more frequent, as there are more reactant particles in the liquid. Increase surface are of the solid again increases the frequency of collision between reacting particles, as the liquid reactant has greater contact with the solid one. The rate of reaction can also be increased by adding a catalyst, but there is not one of this used in this experiment. reaction rate the speed, or velocity, at which a chemical reaction proceeds, expressed in terms of the amount of a product formed per unit time or the amount of a reactant used per unit time.

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7. ## Sodium thiosulphate and hydrochloric acid Investigating how the rate of reaction is affected by Temperature.

Safety Precautions: Throughout this experiment, I made sure that safety was one of my top priorities. I wore goggles at all times to protect my eyes; I had to pour the reactants out extremely carefully as hydrochloric acid is an irritant where as sodium thiosulphate poses no threat to me. Sodium thiosulphate and hydrochloric acid Investigating how the rate of reaction is affected by Temperature. PLAN: Aim: The aim of this investigation is to find out and observe how temperature affects the rate of reaction.

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8. ## Experiment to investigate how changing the concentration of hydrochloric acid affects the rate of its reaction with the reactant

However, I decided to extend my experiment and test marble chips and magnesium again but in a different form. This is because the surface area of the marble chips and magnesium is very random. As we will later figure out, surface area affects the rate of reaction. If the surface area of these two reactants is random then it will affect my results. Therefore I will use magnesium powder and grounded marble chips which will allow me to have more control over the reaction. Experiment 1c: Which reactant reacts best? 1. Display 2 beakers. In: * Beaker 1 place 2g of grounded marble chips * Beaker 2 place 2g of magnesium powder 2.

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9. ## To determine the rate law for a chemical reaction among hydrogen peroxide, iodide and acid, specifically by observing how changing each of the concentrations

The stopcock of the burette was opened to allow the titrant to fill up the tip and then the liquid level was adjusted near zero. 4. The initial burette reading was recorded in Table 1. 5. 1.00 cm3 of the ~0.8 M H2O2 solution was pipetted into a clean 125 cm3 conical flask. 6. 25 cm3 of deionized water was measured with a 50 cm3 measuring cylinder. It was pour into the conical flask. 7. 10 cm3 of 2.0 M sulphuric acid was measured with a 10 cm3 clean measuring cylinder.

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10. ## Factors Affecting Enzyme Activity

When oxygen molecules collide with these carrier molecules they can react to form compounds which are often dangerous. One such molecule is hydrogen peroxide (H2O2) which can attack delicate sulphur atoms and metal ions in proteins thus making it a very dangerous substance to have present in the human body. To combat this the enzyme catalase is used to break down toxic hydrogen peroxide into harmless oxygen and water. The reaction which takes place is as follows: Put simply two molecules of hydrogen peroxide liquid are broken down by catalase into one molecule of oxygen gas and two molecules of water.

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11. ## The effect of concentration on the activity of catalase.

The justification for this prediction is stated in the hypothesis. Figure 7 shows the predicted graph. Background Information: The majority of enzymes are proteins. An enzyme is a biological catalyst. It increases the rate of a reaction without itself being involved in the reaction. The properties of enzymes are: 1. The enzymes are still efficient in small quantities. 2. The enzymes are specific to their reactions. 3. They remain unchanged at the end of a reaction. 4. They lower the activation energy.

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12. ## Investigate the effect of temperature on the rate of reaction

We can measure a change in mass, if the reaction involves a gas being given off. The mass disappearing can easily be measured and recorded over a period of time. Another way to see is by measuring the rate of precipitation. When an insoluble solid forms as a solid in solution, the solution will gradually become more and more opaque. Paper with a mark on it can be used and the time taken for the mark to become invisible can be recorded. Another way to measure the precipitation rate is to use a light meter and data logger to record the amount of light transmitted.

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13. ## What factors affect the activity of urease? What are the kinetics of the urea-urease reaction?

Each type of enzyme will usually act on only one type of substrate molecule. This is because the shape of the active site will only allow one shape of molecule to fit in it. The enzyme is said to be specific for this substrate. There are two types of enzyme inhibitors: Competitive and Non-Competitive inhibition. If an inhibitor molecule binds only briefly to the active site of the enzyme, there is competition between it and the substrate for the active site. This means it is more likely that the substrate will collide with a filled active site and so this is known as competitive inhibition.

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14. ## Change in reaction times due to alcohol consumption.

Therefore, these parts will reach high blood alcohol levels relatively quickly. Alcohol distributes through body water mainly. This means that men, who have on average more body water then women, generally achieve lower alcohol concentration. Men have more body water for two reasons: they are heavier and they have less body fat per kilogram of body weight. Consequently, the same quantity of alcohol per person usually results in a higher blood alcohol concentration in women as compared to men. Alcohol is primarily broken down or metabolized in the liver through two steps mainly: firstly, it is broken down or oxidized to acetaldehyde by an enzyme called alcohol dehydrogenises.

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15. ## Investigation a Chemical Reaction between Sodium Thiosulphate and Hydrochloric Acid

The initial energy is known as the activation energy, it is needed to break the initial bonds. � By increasing the temperature, more energy is given to the particles causing them to move faster. As they move faster they cover more area and therefore are therefore collide more often, from this you can predict that raising the temperature will increase the rate of reaction. I predict with this variable that temperature is proportional to rate of reaction � By increasing the concentration the number of particles will increase. This increases the likeliness of the particles colliding and so the rate increases.

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16. ## Chemistry Coursework Plan: The aim of this experiment is to analyse and understand rates of reaction.

Understanding this I was able to make a hopefully right hypothesis. Reaction between HCl and Mg In the reaction between hydrochloric acid and magnesium ribbon, the hydrochloric acid will dissolve the magnesium and produce hydrogen gas. All chemical reactions involve reactants which when mixed may cause a chemical reaction which will make products. In my experiment the reactants are hydrochloric acid and magnesium ribbon. The chemical reaction takes place when the magnesium ribbon is dropped into the hydrochloric acid. The products that are formed during this reaction are hydrogen gas and magnesium chloride.

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17. ## Rate of Reaction - Sodium Thiosulphate and Hydrochloric Acid Coursework

The time taken for this to happen is the measure of the rate of reaction. We must do this several times, and change the concentration of Sodium Thiosulphate. The rate of reaction is a measure of the change, which happens during a reaction in a single unit of time. The things that affect the rate of reaction are as follows: * Surface area of the reactants * Concentration of the reactants * The temperature at which the reaction is carried out * Use of a catalyst Reaction equation is mentioned above but rate equation could only be decided by doing experiments.

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18. ## Coursework: Effect of Temperature on the Rate of Reaction between

I will then find out and evaluate on how temperature affects this particular reaction. Factors There are four main factors, which affect the rate of reaction that are considered as variables for the experiment I will be doing, they are the following: Molecules can only collide when two of them meet together. This meeting between the two particles can only take place on the surface area of the material. If the surface area of the material is increased, the particles gather more space to collide with each other with force. With a large surface area, the particles will have more area to work on so the collision probability will be high.

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19. ## Effect Of Substrate Concentration On The Activity Of Catalase

BACKGROUND INFORMATION Enzymes such as Catalase are protein molecules which are found in living cells. They are used to speed up specific reactions in the cells. They are all very specific as each enzyme just performs one particular reaction. Catalase is an enzyme found in food such as potato and liver. It is used for removing Hydrogen Peroxide from the cells. Hydrogen Peroxide is the poisonous by-product of metabolism. Catalase speeds up the decomposition of Hydrogen Peroxide into water and oxygen as shown in the equations below. Hydrogen Peroxide---------------------->Water + Oxygen 2H2O2------------------->2H2O+O2 It is able to speed up the decomposition of Hydrogen Peroxide because the shape of it's active site matches the shape of the Hydrogen Peroxide molecule.

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20. ## Measuring the Rate of Reaction between Hydrochloric Acid and Calcium Carbonate

This will be the amount of hydrochloric acid that will be reacted with the calcium carbonate. when the concentration increases the number of particles in a particular volume increases. Therefore, the collision rate increase. Therefore, there will be more successful collisions every second and the rate of reaction will increase. - Catalysts- the catalyst lowers the activation energy for the reaction. Therefore a higher proportion of the collisions will have the activation energy. Therefore a higher proportion of the collisions will have the activation energy.

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21. ## Investigating the effect of enzyme concentration on the hydrolysis of starch with amylase.

The hypothesis presents the enzyme as the 'lock, and the specific substrate as 'key'. The active site binds the substrate, forms a product, which is then released. Diagram 1- a diagram showing the 'lock and key' mechanism works Substrate / molecule fits into active site Reaction occurs Molecule and enzyme combine Products are released from active site Molecule splits in two The 'induced fit' hypothesis mentions that the substrate does not automatically bind with the active site. For the reaction to be possible, the active site has to be changed to activate the enzyme.

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22. ## An investigation to find out what factors affect the rate of a reaction

Each time you cut a slice the surface area increases on to which you can spread butter. The thinner you cut the slices, the more slices you get and butter you can spread. Also by chewing your food, you increase the surface area so digestion can go faster. Size of solid particles increase collisions (surface area) If one of the reactants is solid, then breaking it up will increase surface area. This means the particles around it in solution will have more area to work on so there will be more useful collisions. Catalyst A catalyst speeds up a chemical reaction, only small quantities of the catalyst are required to produce a dramatic change in the rate of a reaction.

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23. ## All roads lead to Rome? The multiple pathways of protein folding

1b). Recently, however, it has been found that the folding of several proteins can occur extremely rapidly (~10-50 msec) in an all-or-none manner that does not involve detectable folding intermediates (see [6] for discussion). These findings raise the issue of whether the observed intermediates generally assist folding, or whether they are the products of off-pathway reactions, having structures that are irrelevant or even detrimental to the formation of the final native state (Fig. 1c). Fig. 1. Three schemes for the kinetic role of protein-folding intermediates. (a) A simple sequential pathway in which the observed intermediates are required to assist folding. (b) A set of parallelpathways in which the folding intermediates accelerate folding, but different competing parallel pathways exist. (c)

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24. ## Find out how the rate of hydrolysis of an organic halogen compound depends on the identity of the halogen atom, and the nature of the carbon-hydrogen 'skeleton'.

The activation enthalpy of one of the haloalkanes at the end of the experiment will be investigated and then calculations for the activation enthalpy will be used. The activation enthalpy of the haloalkane will be calculated by changing the temperature only, while keeping all other variables constant - the concentration of the haloalkane will remain constant during each experiment of different temperatures, and the concentration of the OH- will also remain constant. The activation energy of a reaction can be calculated using the Arrhenius equation: ln k = ln A - (Ea/r)

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25. ## Investigating the effects of temperature on the rate of clotting milk and Rennet

Rennin, found in the substance rennet, is a milk-coagulating enzyme capable of assisting in the production of cheese. Therefore the temperatures at which the milk and rennet coagulate best at in this experiment, are going to be the most suitable temperatures for manufacturing cheese. Rennet can be obtained from the stomachs of young milk-fed mammals, namely calves where the lining of the fourth stomach (the abomasum) is a good source of the substance. Rennet contains the enzyme named Chymosin (Rennin). Chymosin plays a vital part in the digestion of milk inside the calf's stomach. It's job is to coagulate or curdle the milk, and if this wasn't done then the milk would flow rapidly through the calf's digestive system, not allowing the absorption of important proteins.

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