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
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
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
An investigation into the factors that affect The rate of reaction between Sodium Thiosulphate & Hydrochloric Acid
An investigation into the factors that affect The rate of reaction between Sodium Thiosulphate & Hydrochloric Acid AIM: to investigate into the factors that affect the rate of reaction between Sodium Thiosulphate & Hydrochloric Acid. APPARATUS: 50ml Sodium Thiosulphate 0ml Hydrochloric 00ml conical flask distilled water Laminated paper with a x on it Measuring cylinder Stop watch Pipette DIAGRAM: ok this is more or less what my coursework was like i made quite a few changes but hey thats life. hope you find it useful and i will remember this when were at KES! PLAN: there are many factors that could change the rate of reaction- temperature of the liquids, concentration of the liquids, adding a catalyst, the size of particles if one part was a solid. I have chosen to change the concentration of Sodium Thiosulphate each time for the experiment. This is because I feel it is the easiest to do with the time and apparatus available. I am changing the concentration of Sodium Thiosulphate and not the Hydrochloric Acid because there is more volume of Sodium Thiosulphate. I will make up the concentrations of the Sodium Thiosulphate- 0.25 mol dm-3, 0.23 mol dm-3, 0.2 mol dm-3, 0.18 mol dm-3, 0.15mol dm-3, 0.13 mol dm-3 and put them in test tubes. I will measure out the Hydrochloric acid (10ml) and pour it the conical, which is on top of the laminated paper with a
The Periodic Table
The Periodic Table was developed in stages; the first person that attempted to classify elements in relation to their atomic mass was Johann Döbereiner. Döbereiner noticed similar properties between known elements. Theses similarities occurred in groups of threes and were known as 'triads'. The atomic weight of the middle element in each triad is approximately an average of the others. In 1863 John Newlands put the known elements in order of atomic weight and noticed that every eighth element had similar properties, he called this the Law of Octaves. After about 20 elements the table became ragged and some elements had identical places whilst others were incorrect because of inaccurate weights. Furthermore Newlands left no gaps for any unknown elements. Dimitri Mendeleev amended some atomic weight values and left gaps for any undiscovered elements. Mendeleev predicted properties of five elements that should be discovered, within 15 years of his predictions three of these elements had been discovered. One of the unknown elements was called Eka-aluminium today known as Gallium. Below a table compares the predictions made by Mendeleev about gallium with what is now known. Table 1 Comparing Mendeleev's predictions with the properties of element 31, gallium eka-aluminium (Ea) gallium (Ga) atomic weight About 68 69.72 density of solid 6.0g cm-3 5.904g cm-3
Investigating "Green Powder".
Investigating "Green Powder" Introduction The task in hand was to work out what the green powder really is, by running a series of experiments on it. Before the experiments began, we first had to look the container for any hazard signs, this one displayed the harmful sign, and thus meaning it should not be induced. After this, we came up with some questions, to which the answer would help us work out what the green liquid. These questions were: Will it dissolve in water? Does it dissolve in sulfuric acid (H4SO2)? What happens when the powder is heated over a Bunsen flame? With these questions in hand we set out to find the answer to each of them and thus find out what the green powder is. With it dissolve in water? Equipment test tube spatula test tube rack Diagram Method First of all we took a test tube and filled it to 1/3 with water after which we added a spatula full of the green powder, and left in a test tube rack to see if it would dissolve. Results Although it had looked like it had dissolved at first, after time it turns out it had not. (This effect is called suspension, when the molecules of the powder mix between the water making it seem as though it has dissolve, although time reveals that it hasn't) therefore the powder doesn't dissolve in water. Will the powder dissolve in sulfuric acid? Equipment spatula test tube test tube rack pair of
Investigatin the Rate of Reaction
Investigating the Rate of Reaction Aim To investigate the effect of concentration on the rate of reaction between sodium thiosulphate and hydrochloric acid. Prediction I predict that as the concentration of the sodium thiosulphate is increased, the rate of reaction will increase. This is because there are more particles, therefore more chances of collisions. The graph that is going to be drawn in my analysis will have a positive correlation. Also it might be curved as the increase in rate of reaction which will not be exactly the same as the concentration of the sodium thiosulphate. This probably will be because there are more chances of collisions. So when the concentration will increase then the particles would have more energy and therefore it will move faster. This is the reason why they will collide more often. Equipment Substances that we're going to use Pipette Hydrochloric acid Stopwatch Sodium thiosulphate Spotting tile Water Conical flask Funnel Burette Method . Set up apparatus as shown in the diagram. 2. Measure 25cm3 of hydrochloric acid and pour into conical flask. 3. Add 25cm3 of 0.2 mol dm-3 of Na2S2O3 to hydrochloric acid and immediately start stopwatch. 4. When the cross disappears stop the stopwatch. 5. Record the results. 6. Repeat steps 1-5 three more times. 7. Repeat step 1-6 for 0.4, 0.6, 0.8, 1.0 mol dm -3 Na2S2O3.
Disappearing cross (aka Rate of reaction).
Science Coursework Disappearing cross (aka Rate of reaction) Introduction This experiment is to investigate is two liquids, heated to an increasing temperature to see if it will make a reaction take place faster. The experiment I have used is the disappearing cross experiment, where two liquids, sodium thiosulphate and hydrochloric acid are mixed together and eventually the solution will become cloudy. I am going to investigate temperature in both of the liquids, heating them both to the optimum temperature before they are combined. The cross will be hand-drawn on paper and made water proof by covering it with sticky tape, due to it being underwater during the experiment. Once I have all the equipment in place I will mix the two liquids and measure the amount of time it takes for the solution to become cloudy. I will repeat this experiment 3 times to allow my results to be as accurate as possible. Each solution will have 10ml of sodium thiosulphate and 10ml of hydrochloric acid. The chemical reaction formula is: Na2S2O3 (aq) + 2HCL (aq) 2Nacl (aq) + H2O (l) + S (s) + SO2 (g). As a word equation that would be: Sodium Thiosulphate + Hydrochloric Acid Sodium Chloride + Water + Sulphur 4r2