Potato and Osmosis Investigation
Introduction Potatoes contain the enzyme Catalyse which catalysis the breakdown of Hydrogen Peroxide (H2O2) into oxygen and water, the equation for this is: 2H2O2 2H2O + O2 Catalyse Hydrogen Peroxide water + oxygen Catalyse The breakdown of the H2O2 is caused by the enzyme catalyse breaking it down using the lock and key theory. The lock and key theory is where, (in this experiment), the catalyse molecule has an 'active site' which part of a hydrogen peroxide molecule fits into (i.e. lock and key theory). Once a Hydrogen Peroxide molecule has met a catalyse molecule, chemical bonds form between them and then water molecules attack the bonds and weaken them. The hydrogen molecule then breaks up into water and oxygen. The oxygen given off is what we are going to measure in this experiment to calculate the rate of reaction (speed at which the reaction takes place) under certain conditions (in this experiment it will be temperature). This diagram is the enzyme breaking down the substrate, using the lock and key theory. This is what happens when the particles collide with each other (see paragraph below for information on how they collide). There are four different conditions in which the rate of reaction can speed up or slow down, and they are based on the idea of the collision theory. The collision theory is the theory that when particles collide with
This is an experiment to examine how the concentration of the substrate hydrogen peroxide affects the rate of reaction of the enzyme catalase.
Aims This is an experiment to examine how the concentration of the substrate hydrogen peroxide affects the rate of reaction of the enzyme 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. Formula: Catalase Hydrogen Peroxide---------------------->Water + Oxygen Catalase 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 HydrogenPeroxide molecule. This type of reaction where a molecule is broken down into smaller pieces is called an anabolic reaction. Apparatus Needed For The Experiments . Gas Syringe 2. Metal Stand 3. Yeast Catalase 4. Hydrogen Peroxide 5. Test Tubes 6. Beakers 7. Test Tube Rack 8. Stop Watch 9. Pipette 0. Pipette Filler 1. Tap Water Method To test out how the concentration of hydrogen peroxide affects the rate of reaction first set up
To determine the enthalpy change of a reaction.
To determine the enthalpy change of a reaction Aim: The object of this practical exercise is to determine the enthalpy change for this reaction by an indirect method based on Hess's law - Calcium carbonate, CaCO3 decomposes with heat. CaCO3(s) CaO(s) + CO2 (g) An enthalpy change ?H is the heat energy exchange with the surrounding at constant pressure. Analysis I performed an experiment of observing the temperature change before and after each of the reactions between CaCO3(s) and HCl and CaO(s) with hydrochloric acid. Equipment and chemicals were provided. My results from my experiment are presented in the table below: Mass of CaCO3(s) + weighing bottle 2.06g Mass of empty weighing bottle 9.59g Mass of CaCO3(s) used 2.47g Temperature of HCl acid initially 24.5 0c Temperature of solution after mixing 25.0 0c Temperature change during reaction -1 0c Mass of CaO(s) + weighing bottle 1.18g Mass of empty weighing bottle 9.59g Mass of CaO(s) used .59g Temperature of acid initially 24.5 0c Temperature of solution after mixing 34.8 0c Temperature change during reaction -10.3 0c My results table shows clearly that calcium oxide reacted more than calcium carbonate as their was a higher and faster temperature rise being10.3 0c for calcium oxide while reacting with hydrochloric acid, then calcium carbonate of only having a temperature rise
To Determine the Enthalpy Change of a Reaction.
TO DETERMINE THE ENTHALPY CHANGE OF A REACTION PLANNING. CaCO3 --> CaO + CO2 This is the equation for the reaction I intend to find the enthalpy change for. As this particular reaction is very difficult to measure the enthalpy change by carrying it out (the decomposition of CaCO3 needs a temperature of over 800°C), I must use another method and it uses Hess' Law. Hess' Law States: "The enthalpy change for any chemical reaction is independent of the intermediate stages, provided the initial and final conditions are the same for each route." CaCO3 CaO + CO2 CaCl2 + CO2 + H2O In simpler terms, the main point of Hess' Law is that the total enthalpy change for the indirect route of a reaction is the same as the direct route, i.e. ?H1 = ?H2- ?H3. The diagram above represents a Hess Cycle or a Thermochemical Cycle. By knowing the enthalpy changes in two parts of the cycle, it is possible to calculate the third part and complete the cycle. This is how I am going to carry out my experiment. For my experiment I will: .) React calcium carbonate with hydrochloric acid. 2.) React calcium oxide with hydrochloric acid. In both of these reactions I will measure the enthalpy changes by recording the starting temperature and following the reaction, the end temperature. By following this procedure, I can calculate the change in temperature and consequently the enthalpy
To find the effects of the concentration of hydrochloric acid on the rate of reaction on marble chips.
To find the effects of the concentration of hydrochloric acid on the rate of reaction on marble chips. Aim: To find the effects of the concentration of hydrochloric acid on the rate of reaction on marble chips. Introduction: The concentration of acid in a solution is dependant on how many particles there are of the acid in it. As you increase the concentration of the acid, there will be more acid particles in the same volume. For example, if you use the same tap water and pour it into a 100ml beaker and a 1-litre beaker the concentration would be the same. Only if more particles of water are added will the concentration rise. Marble chips can dissolve in acids; if the concentration of the acid is varied then the speed of the reaction will either slow down or speed up. All substances are made out up of particles, before we can get a chemical reaction the particles of the two substances must collide against each other. This is called the collision theory. This means that the higher the concentration of Hydrochloric acid or water the more likely it is that the two lots of particles will collide, the result would be that the rate of reaction would increase. The surface area of solids will increase and decrease on the size of the object. For example if you take one piece of marble and three smaller pieces, the smaller pieces combined will have a larger surface area. For
The rate of reaction.
Background Knowledge The rate of reaction depends on the speed at which a reaction will take place. The speed of a reaction can be observed either by how quickly the reactants are used up or how quickly the products are forming. The rate of reaction can be affected by various factors including temperature, the higher the temperature the more energy the particles will have therefore the number of collisions will increase. It can also be affected by a catalyst, the size of the particles (or surface area) and the concentration. The factor which I am concerned with in this experiment is the concentration of sodium triosulphate and hydrochloric acid. The rate of reaction simply depends on how often and how hard the reacting particles collide with each other. The more collisions that take place will increase the rate of reaction, when the concentration is increased, it means that there are more particles of reactant between the water molecules and hence, a greater amount of collisions taking place. There are three ways to measure the rate of reaction. The first is by precipitation which is when the product of the reaction is a precipitate which clouds the solution. The second method is by measuring the change in mass, usually when a gas is given off. Any reaction that produces a gas can be carried out on a mass balance and as the gas is released, the mass disappearing is easily
The Rate of Reaction
Investigating the The Rate of Reaction Background: A reaction is where two or more atoms collide with each other. These atoms are different substances, when they react with each other they then change to a different substance. The rates of the reaction and how fast they change depends on a number of things, these are: > Surface Area - Surface area is a measure of how much surface is exposed. We find that small pieces of solids, especially powers, react faster than large pieces. As we increase the surface area, we increase the rate of reaction. > Concentration - The acid particles can only react with the marble chips when they collide. As you increase the concentration of the acid, there are more acid particles in the same volume. Therefore, there is a greater chance of acid particles colliding and reacting, with the particles on the surface on the marble. As we increase the concentration, the rate of reaction increases. > Temperature - When you heat the particles, the particles have more energy and move around more quickly. As they travel faster there are more collisions in a certain time. Therefore, reactions get faster as we raise the temperature. At higher temperatures the particles move faster and crash together harder. If you raise the temperature by 10°c, you roughly double the rate of many reactions. As we increase the temperature, we increase the rate of
The rate of reaction between sodium thiosulphate and hydrochloric acid
Rates of Reaction Investigation PLAN Aim: An investigation to find the effect of changing the concentration on the rate of reaction between sodium thiosulphate and hydrochloric acid. Safety Precautions * Tie hair back * Wear goggles at all times * Be careful when using the chemicals * Do not run * Do not sit down during experiment * Tuck in bags and stools. Fair Test To make the experiment a fair test, it must be carried out by: * Using the same equipment each time * Keeping a control to determine whether the experiments have worked correctly * Making sure all of the independent variables are controlled, except ONE which is changed * Make sure the stopwatch is always started at the same time for each test * The temperature should be the same for each test done Prediction I think that the higher the concentration of sodium thiosulphate solution, the quicker the cross will disappear. This means that the graph will have positive correlation. This is explained by the collision theory. Particles have to collide for a reaction to take place. However, only particles with enough energy manage to cause a reaction when they collide. The activation energy is the minimum amount of energy that a particle needs to cause a reaction. The activation energy depends on the reaction, but if the frequency of the collisions increases, so will the reaction rate increase.
The rate of reaction of metals with acid.
The rate of reaction of metals with acid Aim: To determine the order of reaction and the activation energy of the reaction between Magnesium and Hydrochloric acid. To do this I will have to carry out two procedures; one for the order of reaction and one for the activation energy. Background knowledge Rate of reaction In a reaction that takes place between two substances X and Y it is possible to follow the reaction by observing how quickly substance X is used up. The scientific way to see how the rate changes, would be by changing the concentration. The rate of reaction is usually measured as the change in concentration of a reaction species with time. The units of rate= mol dm-3 s-1 Concentration per time Order of reaction For a reaction: A+B+C Products The order of reaction shows how the reaction rate is affected by the concentrations of A, B and C. If the order is 0 (zero order) with respect to reactant A than the rate is unaffected by changes in concentration of A. The way to show this is this: Rate [ A ]0 If the order is 1 (first order) with respect to a reactant B than the rate is doubled by doubling of the concentration of reactant B. Rate [ B ]1 If the order is 2 (second order) with respect to a reactant C than the rate is quadrupled by doubling of the concentration of reactant C. Rate [ C ]2 Combining the information above Rate [ A ]0[ B
Who's cheating on the vinegar?
Chemistry Course Work - Neutralisation of ethonoic acid Who's cheating on the vinegar? Task: A chip shop owner buys his vinegar from 4 different suppliers A, B, C and Safe way. He suspects that at least one of them waters down the vinegar supplied to them by the manufacturer. You are the analytical chemist assigned to investigate this. You have already planned an experiment that will give you the evidence you need. The following results have been taken from a similar experiment. Your task is to analyse these results and present your conclusion. You must then evaluate the experiment by assessing its success in answering the original question, explaining any anomalous results, and suggesting any possible improvements. Aim: I have been asked to find out if any of the suppliers have been watering down the vinegar they have supplied to the chip shop owner. I will do this by using a technique called Titration. Vinegar is ethonoic acid What is Titration? Titration is a form of neutralisation. This is a process of determining the concentration of a substance in solution. A measured amount of a known solution concentration (molarity) is added to an unknown volume of a second solution in carefully measured amounts until a reaction of definite and known proportion is completed. Neutralisation is when a Hydrogen ion and a Hydroxide ion react together to form water which is
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