...Introduction. This is an experiment to investigate into the rate of reaction between sodium thiosulfate (Na2S2O3) and dilute hydrochloric acid (HCl). The formula for this reaction is: Na2S2O3 (aq) + 2HCl (aq) 2NaCl (aq) + S(s) + SO2 (g) + H2O (l). This makes the products Sodium Chloride, Sulphur Dioxide, Sulphur and water Rate of reaction is the speed at which a chemical reaction takes place. Some reaction can take less than a second and other can take over millions of years. During a reaction, we can measure the rate of reaction. The rate of reactions depends on the types of molecules that are combining. There is another thing in rates of reaction called the collision theory. Substances in the liquid, aqueous and gaseous phase consist of particles in rapid and constant motion. The rate of a chemical reaction depends on three factors; the first is - Collision Frequency If a chemical reaction is to happen between two particles, they must first collide. The number of collisions between particles per unit time is known as the collision frequency of the system. This then can be altered by changing the concentration of reactants, total pressure, temperature or the size of the reacting particles. These are all the factors in general that have distinct effects on rates of reaction. The second factor in the collision theory is -Collision Energy Not all collisions result in chemical reactions. Most of the time the colliding particles just bounce off each other. These...
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... What happens when the volume of a mixture at equilibrium is decreased at a constant temperature? I. The value of Kc increases II. More N2O4 is formed III. The ratio of [pic] decreases A. I and II only B. I and III only C. II and III only D. I, II and III (Total 1 mark) 2. Which statement about chemical equilibria implies they are dynamic? A. The position of equilibrium constantly changes. B. The rates of forward and backward reactions change. C. The reactants and products continue to react. D. The concentrations of the reactants and products continue to change. (Total 1 mark) 3. Methanol may be produced by the exothermic reaction of carbon monoxide gas and hydrogen gas. CO(g) + 2H2(g) [pic] CH3OH(g) ∆HO = –103 kJ (a) State the equilibrium constant expression, Kc, for the production of methanol. ...................................................................................................................................... ...................................................................................................................................... (1) (b) State and explain the effect of changing the following conditions on the amount of methanol present at equilibrium: (i) increasing the temperature of the reaction at constant pressure. ..................................................
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...A grade GCSE chemistry coursework - Rates of Reaction Decomposition of Sodium Thiosulphate This is an investigation about the decomposition of sodium thiosulphate. There are many factors (variables) which determine how fast or slow the reaction can take place (rate of reaction). These are: * Initial volume of sodium thiosulphate. * The initial volume of hydrochloric acid. * The initial volume of water. * The temperature of the reaction mixture. * The concentration of the sodium thiosulphate. * The concentration of hydrochloric acid. * Changing the pressure In this particular investigation I am going to find out how heat affects the rate of reaction in the reaction of sodium thiosulphate with hydrochloric acid. Sulphur forms a colloidal precipitate which gives the solution a cloudy yellow appearance. The rate of reaction can be found by measuring the time for the solution to become cloudy. I will measure the amount of time for the solution to become completely cloudy by drawing a cross on a piece of paper and place it under the beaker. As the reaction takes place, the solution becomes cloudy and the cross gradually disappears. The equation for this reaction is: Sodium Thiosulphate + hydrochloric acid → sodium chloride + water + sulphur dioxide + sulphur Na2S2O3(aq) + 2NaCl(aq) 2NaCl(aq) + H2O(l) + S(s) + SO2(g) Preliminary work I have done preliminary work to work out the right amounts/concentrations etc to use and also to decide the best range...
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...Rate of Reaction The rate of a reaction is the speed at which a chemical reaction happens. If a reaction has a low rate, that means the molecules combine at a slower speed than a reaction with a high rate. Some reactions take hundreds, maybe even thousands, of years while others can happen in less than one second. If you want to think of a very slow reaction, think about how long it takes plants and ancient fish to become fossils (carbonization). The rate of reaction also depends on the type of molecules that are combining. If there are low concentrations of an essential element or compound, the reaction will be slower. There is another big idea for rates of reaction called collision theory. The collision theory says that as more collisions in a system occur, there will be more combinations of molecules bouncing into each other. If you have more possible combinations there is a higher chance that the molecules will complete the reaction. The reaction will happen faster which means the rate of that reaction will increase. Think about how slowly molecules move in honey when compared to your soda even though they are both liquids. There are a lower number of collisions in the honey because of stronger intermolecular forces (forces between molecules). The greater forces mean that honey has a higher viscosity than the soda water. Factors That Affect Rate Reactions happen - no matter what. Chemicals are always combining or breaking down. The reactions happen over and...
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...Title How Different Environmental Variables Affect Enzyme Activity Purpose The purpose of this lab is to see if changing the temperature, pH, or concentration of enzymes effects catalase activity. Background Enzymes are in every living thing. Enzymes are catalysts they speed up chemical reactions by reducing the amount of energy needed to perform them. Without them most chemical reactions would happen much too slow for life to exist. Enzymes are very special and each is designed to do one specific thing. One type of enzyme per type of chemical reaction that needs to be catalyzed. There are multiple steps to and enzyme catalyzing a reaction. First, the enzyme floats around and collides with substrates. Substrates the reactants in a chemical reaction. These substrates fit perfectly into the active site of the enzyme, the enzyme then catalyzes the chemical reaction that it is designed for, and this causes the enzyme to momentarily change shape. This new shape is called the “induced fit”. The enzyme then releases the products. The enzyme reverts back to its normal shape once it releases the products and is not permanently changed by the reaction. It then floats around and does it again and again and again. Most enzymes end in the suffix –ase. Temperature is a measure of heat. It is the disorderly movement of molecules. This movement also creates energy. When an object is hot its molecules are moving a lot more and a lot faster than in an object that is cold...
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...Outline for Climate Change Introduction: Why does climate change matter? Biochemically speaking, why is temperature so important? Temperature is critical to biochemical reactions, because it determines the effectiveness of the enzymes controlling the reactions. What is an ectotherm? ectotherms, organisms whose body temperature depends on the surrounding environment. What is the connection between performance and temperature in ectotherms? For these organisms, how fast they grow,1 how quickly they move,2,3 and almost everything else about their behavior and functioning is affected by external temperatures. What is the Goldilocks principle? And to what can it be applied when it comes to temperature? Goldilocks principle when the temperature is just right, enzyme activity is maximized. It is the optimum temperature, where an enzyme or things work at its best. Can be applied to enzymes, performance, population growth rates. How does temperature relate to species richness? As temperature increases the species richness (the number of species in a given area) increases So, what’s the big deal? many biological processes exhibit the same basic hump-shaped relationship with temperature, in which temperatures that are too low or too high impair or sometimes even terminate critical biological processes.1This is why climate change is the focus of so much scientific research. Part 1: Detecting climate change What is the difference between weather and climate? How is this...
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...16th, 2014 Most enzymes are proteins that speed up reactions and are characterized as catalysts. Enzymes work in such a way that when the right chemicals of a molecule are present for the enzyme, it will fully fit the shape. The part of the particular shape is called the active site of the enzyme, since this is where the reaction occurs. The molecule that the enzyme works on is called the substrate. An enzyme reaction includes a substrate (substance) that is converted to another product. The unique shape of the active site of the enzyme allows it to bind with only certain kinds of molecules, which is the substrate of the enzyme (Strobl 2014). A substrate binds to the active site of the enzyme to form a enzyme-substrate complex for a very short time, this then becomes part of a new formation and a new product of a specific reaction is formed then released freeing the active site, allowing the enzyme to repeatedly bind another substrate. Enzymes are produced by all living things, and are a necessity to life. They are responsible for constructing, synthesizing, carrying, dispensing, delivering, and eliminating the many chemicals associated in living organisms (Colpa 2014). An example for how enzymes work in living organisms would be the process of food digestion, enzymes work to break down food and speed up the digestion process. Factors that affect enzyme activity deal with environmental conditions, which are temperature, salt concentration, and also pH concentration. These...
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...that are found throughout the body, with their main function being to act as biological catalysts. An enzyme can act to speed up or regulate the rate of the reaction, in order to maintain an efficient rate of biological reactions. Enzymes, whilst having an important role in the reaction of many chemicals within the body, are not consumed in the reaction, and so are able to catalyze many reactions in their life cycle. Enzymes are able to reduce the activation energy of the reaction; the energy required to break bonds between the reactants, and form new bonds in the products, which allows more product to be formed. (Marieb and Hoehn, 2010, pp.51-53). Enzyme activity is affected by changes in the pH of their solution. For each individual enzyme, there is a corresponding pH at which, that particular enzyme’s activity will be at it’s maximum. This is known as the optimum pH. If the pH of the solution is getting closer to it’s optimum pH for that particular enzyme, then the activity of the enzyme, and therefore it’s rate of reaction, will increase. At extremes of pH (either extremely acidic or basic) enzymes tend to become denatured; a state in which they lose all of their biological activity. (Worthington Biochemical Corporation, 2011). Temperature has the ability to increase the reaction rate of chemical reactions, by increasing the kinetic energy of the molecules themselves. By increasing the kinetic energy of the molecules, there will be a greater proportion of molecules...
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...Running head: LAB 5: INVESTIGATING AN ENZYME-CATALYZED REACTION Lab 5: Investigating an Enzyme-Catalyzed Reaction September 24, 2014 Principles of Biology 120.601 Mrs. Annemarie Duncan Abstract: (Burmania) This experiment was performed in order to examine ways in which a potato catalase enzyme reacts to various assays with differing variables. To do so a baseline assay (undiluted extract and room temperature H2O2) was used within the experiment with only one other variable changed in the other assays. These variables included a boiled, frozen and then thawed, and frozen potato extract and dH2O instead of the potato extract. It was noted that the temperature and or way the potato extract was prepared effects how the enzyme with the potato will react. Therefore the results of each assay varied, suggesting there is more than one way that a catalyzed reaction can occur. Introduction: (Burmania) The main purpose for this experiment was to explore how an enzyme catalase caused a reaction to catalyze through doing various assays using potato extracts. Enzymes are catalysts that are crucial in helping to speed up reactions, and catalase is a common enzyme found in almost every living organism that is exposed to oxygen. For this experiment, potatoes were used because they were previously known to have significant catalase activity. The potato catalase was mixed with hydrogen peroxide because the catalase helps to breakdown the hydrogen peroxide which helps determine...
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...respiration? * Glucose = Lactic Acid * Glucose = Ethanol + Carbon Dioxide (=energy) – with this equation the ethanol and Co2 breaks downs the sugars into products e.g. like bread is made using yeast where the sugar breaks down into products. FERMENATION is where things respire anaerobically. What is the job of an enzyme? * To speed up chemical reactions, as they are proteins. What needs to be constant for enzymes to work? * Temperature,( however if too high the enzymes de-natures) What is the optimum PH? * Where the enzyme is most active as that is where they work their best, however if the PH is too low or high it affects the bonds holding the enzymes together therefore, changing the shape of the active site… the enzyme denatures. What is the function of a DNA molecule? * It contains the genetic code for enzymes involved in respiration The functions of plants & animal cells are: * Mitochondria are where enzymes are, where aerobic respiration reactions take place. * Cytoplasm is a gel-like substance where anaerobic respiration takes place as some controlled enzyme reactions take place here. * Cell membrane is what controls what goes in and out of the cell as it acts like a barrier allowing water & gases to pass through easily. What does the bacteria cell consist of? * They have a simple cell structure of a circular DNA molecule which floats in the cytoplasm, cell wall and cell membrane. What does a plants cell...
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...power. Fire kills more people every year than any other force of nature. The dangerous thing about the chemical reactions in fire is the fact that they are self-perpetuating. The heat of the flame itself keeps the fuel at the ignition temperature, so it continues to burn as long as there is fuel and oxygen around it. The flame heats any surrounding fuel so it releases gases as well. When the flame ignites the gases, the fire spreads. So it is important that we understand the process of how it works to better protect ourselves from the dangers of fire. People used to considered fire as one of the major elements in the universe, alongside water, earth and air. But fire is really something completely different. Earth, water and air are all forms of matter; they are made up of millions and millions of atoms collected together. Fire isn't matter at all. It's a visible side effect of matter changing form. It’s one part of a chemical reaction. Typically, fire comes from a chemical reaction between oxygen in the atmosphere and some sort of fuel (wood or gasoline, for example). Of course, wood and gasoline don't spontaneously catch on fire just because they're surrounded by oxygen. For the combustion reaction to happen, you have to heat the fuel to its ignition temperature. The sequence of combustion generally goes like this: Something heats the wood to a very high temperature. The heat can come from lots of different things for example a cigarette or lightning. When the wood reaches about...
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...Kinetics Experiment The Rate of a Chemical Reaction: A Clock Reaction Andrea Deoudes February 2, 2010 Introduction: The rates of chemical reactions and the ability to control those rates are crucial aspects of life. Chemical kinetics is the study of the rates at which chemical reactions occur, the factors that affect the speed of reactions, and the mechanisms by which reactions proceed. The reaction rate depends on the reactants, the concentrations of the reactants, the temperature at which the reaction takes place, and any catalysts or inhibitors that affect the reaction. If a chemical reaction has a fast rate, a large portion of the molecules react to form products in a given time period. If a chemical reaction has a slow rate, a small portion of molecules react to form products in a given time period. This experiment studied the kinetics of a reaction between an iodide ion (I-1) and a peroxydisulfate ion (S2O8-2) in the first reaction: 2I-1 + S2O8-2 I2 + 2SO4-2. This is a relatively slow reaction. The reaction rate is dependent on the concentrations of the reactants, following the rate law: Rate = k[I-1]m[S2O8-2]n. In order to study the kinetics of this reaction, or any reaction, there must be an experimental way to measure the concentration of at least one of the reactants or products as a function of time. This was done in this experiment using a second reaction, 2S2O3-2 + I2 S4O6-2 + 2I-1, which occurred simultaneously with the reaction under investigation. Adding starch to...
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...Introduction Every animal has their own optimum temperature in which they are able to survive Daphnia are small aquatic crustaceans...(). The daphnia’s exoskeletons are transparent which allows their heart to be visible, which makes it simple to observe the heartbeat rate without cutting them open (). The rate of the daphnia can be monitored and counted in different conditions such as changing water temperature. Daphnia are ectodermic animals which mean that they do not perform thermoregulation they rely on their external environment to warm their internal bodies, the water temperature they float in is the same as their body temperature. Ectoderm animals use a small amount of energy to maintain their body temperature since they rely on the environment but they are also disadvantaged because they are limited as to the environments that they can inhabit as the case of Daphnia they are water fleas so they can retain they source of temperature regulation in the water they live in ().Other animals like human, birds and most mammals may have a different reaction under the same temperature conditions because they are endodermic: they perform homeostasis of body temperature (thermoregulation) which maintain a constant body temperature irrespective of their external...
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...different parts of the molecule. A catalyst is a material that donates energy to reactants in order to reduce their activation energy. In other words, they allow reactions to occur with less energy input (i.e. more quickly or at lower temperatures). The very specific shape of enzymes allows them to “fit” into a reaction and reduce the energy necessary for the reaction to occur. If their shape is changed, their ability to function as a catalyst is reduced or eliminated. As biological catalysts, enzymes are important because they speed up the rate of the reaction they catalyze that would otherwise be too slow to support life. Factors Affecting Enzyme Activity The rate at which an enzyme works is influenced by several factors including temperature and pH. Enzymes are most effective as catalysts under optimum physical and chemical conditions; as conditions change away from optimum, enzyme activity decreases (Figure 1.). Changes in various environmental factors, such as temperature or pH, may affect proteins by altering their shape; with loss of shape comes loss of function causing the protein to become denatured. Denaturation is often a reversible process. Figure 1. Effects of Variable Temperature and pH on Enzyme Activity The Effects of Temperature on Enzyme Activity Under ordinary conditions, at any given temperature, molecules possess a range of kinetic energy (Ek). A portion of...
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...An experiment to show effect of the temperature on the action of an enzyme Abstract The experiment was to analyse what reaction temperature would have on Amylase enzyme. We heated alpha amylase solution to set temperatures then tested for the presents starch with iodine solution. Any starch would turn the iodine black. Once the starch had broken down the iodine would remain brown to suggest the presents of maltose. Usually I would expect to find that the reactions would increase as the temperature increased. After it reached its optimum temperature then the reaction would slow down rapidly or stop all together. However throughout the experiment we uncovered a number of flaws, the flaws would have contributed to the failure of this experiment and the rejection of my hypothesis. Introduction Enzymes are proteins that were made during protein synthesis. They are globular in shape and of a tertiary structure that has an active site. The protein molecules act as a catalyse biochemical reaction in living organisms. (Indge, B (1993), A-Z Biology. London. Wearset. 90). A catalyse is something that makes a chemical reaction happen more quickly without itself being changed. This means that enzymes can be re-used. Enzymes work by lowering the activation energy necessary to start a reaction. As less energy is necessary, biochemical reactions can take place at the temperatures and pressures found in living cells. (Indge, B (1993), A-Z Biology. London. Wearset. 90). ...
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