Using Simple cells to find an order of reactivity in metals
Using Simple cells to find an order of reactivity in metals In electrochemical cells a chemical reaction occurs in the "cell" causing an electrical current to be generated. The electrochemical cell is made by dipping two metals into a solution which allows electricity to pass through it. In this experiment a solution containing ammonium chloride is used. The Aim The aim of this science assessed practice is to use my data to confirm the position of the metals in the reactivity series. Apparatus Voltmeter 2 leads with crocodile clips Beaker (approximately 100cm3) Emery paper Ammonium chloride solution Strips of the following metals: Zinc Copper Magnesium Lead Tin Aluminium Nickel Procedure . Clean the metals with emery paper. 2. Half fill the beaker with ammonium chloride solution. 3. Connect two wires to the voltmeter. 4. Using crocodile clips connect a piece of one metal to wire and a different metal to the other wire. 5. Dip the two pieces of metal into the solution and record the HIGHEST reading given in the table 1. 6. Repeat steps 1-5 testing all the metals as indicated in the results table 1 (N.B. If the voltmeter reads a negative value make a note of the sign.) DIAGRAM OF APPARATUS Fair Test I measured the voltage and sign the positive or negative value in order to find the reactivity series. The only variable in this practice is the type of
Petrol - In its crude state, petroleum is a virtually useless material.
Petrol In its crude state, petroleum is a virtually useless material. However when refined, the hydrocarbons it contains supply almost half the world's current energy needs and are the starting chemicals from which about 90% of the worlds organic chemicals are made. Fractional distillation is the process by which the different fractions in crude petroleum are separated according to their boiling points. One of the fractions obtained is naphtha. Further fractionation of naphtha yields petrol (C - C alkanes). In the internal combustion engine, a piston compresses a mixture of air and petrol vapour. At the point of maximum compression, an electrical spark ignites the petrol/air mixture and rapid combustion occurs. A typical reaction would be the combustion of octane: The hot gaseous products expand against the piston and force it downwards. This mechanical energy is transmitted to the drive wheels of the car, enabling it to move. Petrol also contains various additives such as lubricants, rust inhibitors and anti-knock agent. Some hydrocarbons have a tendency to ignite spontaneously before maximum compression is achieved. This premature explosion, known as knocking, still forces the piston downwards and powers the vehicle. However, the chemical energy in the petrol is less efficiently converted into mechanical energy. As a result, the vehicle will do fewer miles per gallon.
Mass Spectrometer Used to determine * the relative isotopic masses and abundance of isotopes * the relative molecular mass (Mr) and abundance of the organic compound Principles of the mass spectrometer * Apparatus enclosed in total vacuum, so that there are no colisions between the sample being investigated and the atmospheric air or the residue from previous samples. * Vacuum pump is to reduce pressure so less thermal energy is needed to vaporise the sample. The pump is to remove any traces of the previous sample traces of the air. * Sample under analysis must be vaparised i.e. converted to gaseous state. This is achieved by heating it in the furnace. * Sample then enters the ionisation chamber; here the sample is bombarded by a beam of high energy electrons. A beam of these high energy electrons bombard the atoms causing them to loose an electron. A removal of an electron from the atom is known as ionisation. This results in the formation of positively charged ions (cations), mainly single charged ions. If the sample is simple the molecules are ionised by being bomdarded by high energy electrons, causing bonds to vibrate and weaken, some bonds between molecules to produce small pieces of the original molecule known as smaller fragments and/or free radicals. Smaller pieces of the original lecule are known as moecular
Osmosis - how does the concentration of water affect the mass of a potato?
Biology Coursework Osmosis- how does the concentration of water affect the mass of a potato? Abubakar Hatimy Aim: - My aim is to find the percentage change of mass when a small piece of potato is placed in to molar sucrose solution Apparatus: o Molar sucrose solution 0.0 - 0.5 o Potato o Cutting board o Knife o Weighing machine o Glass test tube o Glass test tube holder Plan: - My plan is too find the percentage change of mass of a small piece of potato when placed in to molar sucrose solution by using osmosis. Osmosis is explained below Osmosis Osmosis is the passage of water molecules from a region of their high concentration to a region of their low concentration through a partially permeable membrane. It is best regarded as a form of diffusion in which only water molecules move. For example look at Figure 2. The solute molecules are too large to pass through the pores in the membrane, so the movement of water molecules can only achieve equilibrium. Solution A has the higher concentration of water; so there will be a net movement of water from A to B by osmosis. At equilibrium there will be no further net movement of water. The tendency of water molecules to move from one place to another is measured as the water potential, represented by the symbol
To investigate the effect of varying concentration of glucose solutions on the osmotic activity between the solution and potato slices.
INVESTIGATING OSMOSIS IN PLANT CELLS AIM: To investigate the effect of varying concentration of glucose solutions on the osmotic activity between the solution and potato slices. SCIENTIFIC THEORY: Osmosis is defined as the net movement of water molecules from a region of high concentration to a region of low concentration of water, through a partially permeable membrane, which only lets smaller molecules through. This can also be described as movement down the concentration gradient. The molecules continue to diffuse through the membrane until both sides reach a state of equilibrium. This is also known as the isotonic point when the molecules are equally distributed on both sides of the membrane so that no one area has a higher or lower concentration than the other. Plant cells have a strong cell wall and a partially permeable cell membrane around them. When cells are surrounded by a solution more dilute than their own, (hypotonic solution-with more water than solute molecules), the cell swells up and becomes "turgid". This is because the water molecules diffuse from the solution to the plant to equal out the concentration levels. The strong cell wall prevents them from bursting. Figure 1- A turgid plant cells in more dilute surroundings (from "Biological Sciences Review") When they are surrounded by a solution more concentrated than their own, (hypertonic- less
Investigating Impact Craters
PHYSICS INVESTIGATION INVESTIGATING IMPACT CRATERS The Aim of this investigation is to determine relationships between the following variables: * The height from which a ball (a simple model of an asteroid or meteor) is dropped and the diameter of its impact crater. * The height from which a ball is dropped and the depth of its impact crater. * The diameter of a ball and its impact crater. * The mass of a ball and the diameter of its impact crater. * The mass of a ball and the depth of its impact crater. * The angle at which the ball impacts and the length of its impact crater. * The angle at which a ball impacts and the depth of its impact crater. * Keeping the angle the same, changing the magnitude of the ball's velocity - and measure the length and depth of impact craters. * Changing the vertical height dropped by the ball, after being released at an angle. Preliminary Experiments In order to get the best range of results some preliminary work was required. Firstly the material which was to be dropped into needed to be decided upon. The three main options are as follows: . Flour This was initially intended as the impact material, however after some early tests it was found that the flour would not hold its shape correctly after the ball had been removed from the impact crater. This lead to the diameter of the craters being changed greatly from the expected
Investigation to see what effect different concentrations of solution has on osmosis
INVESTIGATION TO SEE WHAT EFFECT DIFFERENT CONCENTRATIONS OF SOLUTION HAS ON OSMOSIS Osmosis is the movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration. Aim The aim of the experiment is to investigate what effect different concentrations of solution has on osmosis. Prediction I think that in a more concentrated solution of molar, the potatoe chip will lose more weight, than in a solution less concentrated. In pure water, the potatoes will swell due to water entering their cells by osmosis. However, in rich sugar solution i.e 1 Molar, the potatoe chip will shrink as water is leaving thwe cells by osmosis. Test tube 1, will be for sugar solution, test tube 2 for 0.5 Molar and test tube 3 for pure water solution i.e 0.0 Molar. Apparatus * Test tubes (x3) * Measuring Cylinder * A stop watch * Sieve * Potatoe chips * Weighing scale * Ruler * Knife Fair Test For the results to be the most accurate and reliable they can, I will repeat the experiment four times. For the investigation to be a fair test, the following should and will be considered: * The pieces of potato must be the same width and length, as they must have the same surface area given to the solutions. This means that if one cylinder is given more solution than another cylinder, then the one with the larger
Planning - Variable input - Alcohol
SKILL P~PLANNING Input Variables Alcohol This is the variable I am going to investigate. An increase in the length of carbon-carbon chains will result in an increase of energy given out. This is due to the longer hydrocarbons having, a greater attraction to each other. Therefore more energy is needed to break them down so more energy is given out since the reaction is exothermic. Volume of Alcohol A greater volume means more molecules of the alcohol. More molecules will mean more atoms, hence more carbon-carbon chains. As is described above more carbon-carbon chains in this experiment will mean more energy. Therefore to keep this variable constant each alcohol will have the same number of molecules. Isomers of Alcohol Isomers may have different structures., and they may have different properties. We know that branched chains have lower boiling points then straight ones. Therefore to make sure that isomers do not effect the experiment only one isomer from each alcohol will be tested. Volume of Water To keep this variable constant the same volume of water for each experiment will be used. Mass of Ceramic Wool To keep this variable constant the same mass of ceramic wool will be used. Container To keep this variable constant only one container will be used for the whole experiment Height of Container To keep this variable constant the container will remain at the
To find out how the length of a piece of wire effects the reaction time in a circuit.
Physics Coursework. Planning: Aim: To find out how the length of a piece of wire effects the reaction time in a circuit. Background and general information: In this course work investigation I will be trying to find out if the length of a piece of wire which is joined into a circuit effects the resistance. There is many reasons why the wire may cause more or less resistance. The length, temperature, thickness and the material the wire is made out of are all factors, which will effect resistance. I have decided to test how the length of the wire effects resistance as it is the easiest experiment to perform. Temperature and thickness of wire would be far too hard to set up and changing the type of material used each time for the wire would yield small results as we could only use maybe 5 or 6 different metals. In my experiment I will only be recording the resistance from the different lengths. However the materials, temperature and thickness will still be very important, as they will still effect the resistance. I will try and keep the same wire each time simply making it shorter so it is the same material each time. AS it is the same wire the thickness won't change either. The temperature of the wire should not change either, as I will be putting the same current in for each try. I will need lots of results but not too many. To make this possible I will be removing 5
Rates of Reaction- Hydrolysis of Urea by Urease
The Effects of Temperature and pH on the Hydrolysis of Urea by Urease By Justine Hyu Abstract: The relationship and effect of both temperature and pH, on the enzyme urease was investigated. This was accomplished by initiating the hydrolysis of urea by urease in different variables in order to show changing enzyme activity. Several theories which involved the optimum conditions of urease were explored during the experiment, and in effect were highly involved with the modelling of the experiment. Many expected results were obtained, some of which applied to the researched theories. However, although this experiment was functional there, overall, improvements and adjustments could be made to enhance accuracy. Aim: The aim of this experiment is to investigate the optimum temperature and pH of the enzyme urease, and to show the diverse effects of both variables. Hypothesis: As the temperature increases, urease enzyme activity will rapidly increase until reaching its maximum potential of 50°C, where the rate of reaction is at a peak. After this point the enzyme will denature and become inefficient. Urease will be less active in acidic and basic environments but will work most efficiently in more neutral surroundings; meaning that urease will be less active in a solution of a low pH and high pH, but at a neutral pH of 7 it will function at its best. Introduction and