Observing emission spectra
DATO: 19/09-07 NAME: SULEMAN ESAM Exercise Observing emission spectra Aim: To see different kinds of spectrums, and their appearance. Equipment: - Spectrometer - Magnesia rods - HCL ca. 6 mol dm-3 - Mercury discharge tube - Safety glasses - burner - NACL - KCL - CACL2 - BACL2 - CUCL2 - LICL - SRCL2 Procedure: Part 1: First I looked at a patch of daylight through the spectrometer and saw a continuous spectrum. Then I dipped the magnesia rod into 6M HCL and burned it very quickly. I looked through the spectroscope and saw an orange line. Afterwards I dipped the magnesia rod into 6M HCL and then into one of the solid compounds and burned it, and saw it through the spectroscope. I repeated this with every compound. The result showing in the spectroscope is given in the chart below. Compound Violet Green Yellow Orange red NACL ? KCL ? ? ? CACL2 ? ? ? BACL2 ? CUCL2? ? ? SRCL2? ? ? ?In CUCL2 every lines from violet-green was visible ? In SRCL2 every lines from orange-red was visible PART 2: . I turned on an incandescent lamp and looked at it through a spectroscope. I saw a continuous spectrum. 2. Then I saw the fluorescent lamp through a spectroscope, and I saw all the colours, but they are in the background, except 4 specific colours. Violet, blue, green and red. 3. With use of mercury discharge tube, I saw some gases
Aim: to determine the concentration of sodium hydroxide by titration potassium hydrogen phthalate
DCP LAB: ACID-BASE TITRATION Aim: to determine the concentration of sodium hydroxide by titration potassium hydrogen phthalate Raw Data Amount of Sodium Hydroxide to Titrate Potassium Hydrogen Phthalate Trial Amouunt of NaOH (±0.05ml) 24.60 2 25.20 3 25.00 Processed Data Uncertainties: Electronic Balance : ± 0.01g Pipette : 25 ± 0.05ml Burette : 50 ± 0.05ml Amount of KHC8H4O4 used : 2.00 ± 0.01 g Molar mass of KHC8H4O4 : 202.40 g/mol No of moles in KHC8H4O4: (2.00/202.40) = 0.00988 moles Conversion of amount of NaOH(ml to dm-3) Trial Amount of NaOH in dm-3 0.0246 2 0.0252 3 0.0250 Concentration of NaOH Trial Concentration of NaOH (mol dm-3) 0.00988/0.0246 = 0.402 mol dm-3 2 0.00988/0.0252 = 0.392 mol dm-3 3 0.00988/0.0250 = 0.395 mol dm-3 Propagation of Error Percentage error in mass of KHC8H4O4: (0.01/2.00) x 100% = 0.500% Percentage error in volume of NaOH in multiple trials Trial Percentage error in volume of NaOH (0.05/24.60) x 100% = 0.203% 2 (0.05/25.20) x 100% = 0.198% 3 (0.05/25.00) x 100% = 0.200% Concentration = no. of moles / volume Percentage error in concentration of NaOH in multiple trials Trial Percentage error in concentration of NaOH Concentration: 0.00988/0.0246 = 0.402 mol dm-3 Percentage Error: 0.5% + 0.203% = 0.703% Concentration of NaOH: 0.402 ± 0.703% 0.402 x 0.703% = 0.00283 0.402 ± 0.003
Separating 3 solids
Separating 3 solids Procedure: * 5.4g. of Sand, 7.4g. of Copper Sulfate and 8.3g. of Iron Filings are mixed together with a spatula in a beaker. * A magnet is then produced and the small-grey Iron is extracted. * Filter Paper is used to filter out the damp Sand. * A clear-blue Copper Sulfate solution is obtained. * Copper Sulfate solution is poured into an crystallising basin. * Basin is left for a full week along with the damp Sand. * Copper Sulfate crystals are produced. D.C.P.: Weight Before (g) After Iron Filings 8.3 8.3 Sand 5.4 5.5 Copper Sulfate 7.4 7.3 Conclusion/Evaluation: Only slightly less of each material was obtained after the separation, leading to a relatively low level of loss and error. In order to simplify the separation of the Iron Filings, and solve the problem of small pieces of Iron staying attached to the Magnet, I decided to wrap the magnet with a thin layer of paper towel that could then slide off the magnet to release the Iron Filings and drastically decrease the chances of losing pieces of Iron. The Sand weighed more after rather than before because it still had some water in it, whilst the Copper Sulfate weighed slightly less because of loss in small fragments of Copper Sulfate crystals left in the crystallising basin - both Copper Sulfate before and after were in the form of crystals and therefore contained water. One
The effect of concentration on the reaction rate:
The effect of concentration on the reaction rate: I) Aim: Observe the effect of concentration on the reaction rate. II) List of equipment: - 155 cm3 of sodium thiosulphate solution - 150 cm3 of water - 25 cm3 of hydrochloric acid - flask - cylinder - timer - safety goggles - lab coat - a paper with a black cross on it III) Method: * We put 50cm3 of 40g/dm3 sodium of thiosulphate solution in a flask and then we put 5cm3 of hydrochloric acid and we start the timer. When we could not see the cross anymore, we stop the timer and we note the time. * Then we redo the processes with different concentration of sodium thiosulphate solution by adding water. IV) The table of results: Volume of sodium thiosulphate solution (cm3) Volume of water (cm3) Time taken for the cross to disappear (s) Concentration of the sodium thiosulphate solution (g/dm3) Rate of the reaction (/s) 50 0 25 40 /25 = 4.00*10-2 40 0 30 32 /30 = 3.30*10-2 30 20 38 24 /38 = 2.60*10-2 20 30 65 6 /65 = 1.55*10-2 0 40 40 8 /140 = 7.15*10-3 5 45 334 4 /334 = 3.00*10-3 V) Graph: In this experiment there is three types of variable: the independent variable which is the concentration of sodium thiosulphate solution; the dependent variable which is the rate of reaction and the constant variable which is the temperature, the volume of hydrochloric acid and
How Do Acids React With Metals
HOW DO AcIDS REACT WITH METALS? Seren SAPMAZ 9C 582 Purpose: To observe the reaction of metals with acids, and to determine the forming of salt and hydrogen gases' Materials: 6 Test tubes 6 Test tubes (bigger than others,to collect the hydrogen gas inside it) Test tube clamp 2 Beakers (100 ml) Dropper Safety glasses Electronic heater Hydrochloric acid, Sulphuric acid A piece of Zinc A piece of Aluminum A piece of Copper Procedure: . Take six test tubes, write numbers on them. 2. Put Al in 1 and 4, Zn in 2 and 5, and Cu in 3 and 6. 3. Use the dropper drop some Hydrochloric acid in tube 1, 2 and 3. 4. Take another 3 test tubes above the tube number 1, 2 and 3 to collect the gas formed. 5. Repeat step 4 using Sulphuric acid instead of Hydrochloric acid, on test tubes 4,5 and 6 . Metal After HCl H2 Test After H2S04 H2 Test Zn Reaction Hydrogen Reaction Hydrogen Al Reaction Hydrogen Reaction No H2 but SO4 Cu No reaction No H2 No reaction No H2 Concluison: We have done this experiment and observed how the reaction between acids and metals is. Our experiments were successful. We couldn't determine the hydrogen gas in Cu reaction with HCl and there was no reaction between them either. We couldn't determine hydrogen gas in Al and Cu reaction with H2S04,but there was a reaction between Al and H2S04. To make an experiments with acids are
Lab report: the effect of temperature on the rate of reaction
The effect of the temperature on the rate of the reaction Aim: to develop a method for studying how an increase in temperature affects the rate of a reaction Materials: digital thermometer, boiling tubes, test tubes, 3 burettes, potassium iodide solution, sodium thiosulphate solution, freshly made starch solution, stopwatch, heater Independent variable: the temperature of the water in the beakers Dependent variable: time of the reaction Controlled variables: the volumes of sodium thiosulphate, potassium peroxodisulphate, starch solution, potassium iodide, the mass of the beaker, the mass of the test tube Procedure . Add 25cm3 of 0.2mol dm-3 of potassium iodide solution(KI), 35cm3 of 0.1mol-3 potassium peroxodisulphate(K2S2O3) solution, 20cm3 of 0.01mol-3 sodium thiosulphate (Na2S2O3) into different burettes. 2. Add 3cm3 of 0.2mol dm-3 of potassium iodide solution(KI), 4cm3 of 0.1mol-3 potassium peroxodisulphate(K2S2O3) solution, 2cm3 of 0.01mol-3 sodium thiosulphate (Na2S2O3) into a test tube. 3. Add 150cm3 of water into a 250cm3 beaker. 4. Heat the water until it reaches 20°C. 5. Put the test tube into the water in the beaker. 6. Start the stopwatch immediately. 7. Record the time taken for the solution in the test tube to change. 8. Repeat 1 -3 with temperatures ranging from 30 to 70°C. 9. Repeat the whole experiment again. 0. Name the first
Aim To determine the concentration of a sulphuric acid by titration against a standard solution of sodium carbonate just prepared
CHAN CHI HEI 6LS(1) Title Standardisation of sulphric acid Aim To determine the concentration of a sulphuric acid by titration against a standard solution of sodium carbonate just prepared Result Trial st 2nd 3rd Final Burette Readings/cm3 0.20 4.80 9.50 24.10 Initial Burette Readings/cm3 5.00 0.20 4.80 9.50 Volume used/ cm3 5.20 4.60 4.70 4.60 Mean volume used/ cm3 4.63 Calculation Na2CO3(aq)+H2SO4(aq)-->Na2SO4(aq)+H2O(l)+CO2(g) Since Na2CO3: H2SO4 = 1:1 No of mol in H2SO4 = 0.1 x (25/1000) = 2.5 x 10-3 mol Then the concentration of H2SO4 = (2.5 x 10-3 ) / (4.63/1000) = 0.5399M Discussion During the experiment ,there may be some possible error and some of them can be minimized. First, the water inside the burrete may affect the concentration of sulphuric acid. To prevent this , we need to rinse the burrete with sulphuric acid. Also , we need to make sure the top of burrete is filled of s sulphuric acid. Simiarly , the pipette should be rinsed with the sodium carbonate solution before. Also, our eye level should be horizontal to that of the water level so that the data recorded will be more accurate. And there are also a precaution during the experiment. Gloves and safety goggles should be weared to prevent the acid contact with our bodies. After doing the experiment , I think some improvements can be made. During titration , I find
Dissolving and Energy Changing
SPH Dissolving and Energy Changing Science Experiment Sarah Harefa 10.4 Solutions Initial Temperature (°C) Final Temperature (°C) NH4NO3 22 9 KCl 21 9 Na2CO3 22 9 NaNO3 20 8 KNO2 21 8 NaOH 21 32 Temperature Changes of Dissolved Solutions in Distilled Water Evaluation: The overall outcome of the experiment is really good. We learn new things about endothermic and exothermic reactions and be acquainted with lab more. However during the experiment, there are few flaws groups keep making. First of all, the thermometer flaw; we must record the initial time of the water to know what type of reaction is occurring and read thermometer in on eye level. It's very crucial if we groups keep making the flaws, the experiment will become unreliable. Secondly, instruments hygiene; we must clean thermometer with water and dry it off with tissues to avoid other solutions to be contaminated and clean the instruments afterward with clean brush and soaps to avoid serious damage. Conclusion: This experiment thought us more about exothermic and endothermic reaction. Solutions such as NH4NO3, KCl, Na2CO3, NaNO3, and KNO2 are all endothermic reaction as the Final temperature fall by an average of 2.6°C from the initial temperature of 20-22°C. It proves that the energy from surrounding is absorbed to into the system which is the solutions and breaks the chemical bonds.
Factors affecting Galvanic Cells
Factors affecting Galvanic Cells Problem: If and how changes in the solutions as well as their concentrations affect the voltage in a galvanic cell? Variables: - Independent: * Type of solution used: Cu(NO3)2, Zn(NO3)2, Pb(NO3)2 * The concentration of the each solution. - Dependant: * The mass change in the cathode and anode - Controlled * The amount of time * The metals used for both rods * The temperature of the solutions Materials: - Power supply - Voltmeter - Zinc and Copper metal rods - Circuit wire - Beakers - Salt Bridge - Sand Paper - Crocodile clips - Graduating Cylinder - Cu(NO3)2, Zn(NO3)2, Pb(NO3)2 - Weight Scale Procedure: - Set up a beaker with 300 mL of 1M Cu(NO3)2 - Set up the voltmeter so it's connected to the power supply, correctly and with crocodile clips - Set up the beakers and the salt bridge as shown in the diagram - Obtain small strips of filter paper, to be used as salt bridges. Wet each strip with Cu(NO3)2 and insert into the solution. Repeat for each of the three remaining salt solutions. - Start the power supply for 5 minutes and record the amount of voltage created. Do so three times and record the information - Repeat above steps for 0.5M, 1.5 M and 2M and then repeat so with the remaining
Polarity testing. Aim: To determine whether the following liquids are polar or non-polar in nature
Testing liquids for polarity-Chemistry lab Abhay P. XI D Aim: To determine whether the following liquids are polar or non-polar in nature Apparatus: - Cyclohexane, Distilled water, Carbon tetrachloride, Ammonia solution, Cyclohexene, Benzene, Acetone, beaker, burette, funnel. Observations Compound Formula Structural formula Deflection Cyclohexane C6H12 Yes- Small Cyclohexene C6H10 Yes- Very Small Benzene C6H6 No Deflection Ammonia NH3 N H H H Yes- Large Distilled water H2O O H H Yes- Largest Carbon tetrachloride CCl4 Cl C Cl Cl Cl No Deflection Propanone CH3COCH3 Yes- Average Deflection Inference Wherever deflection occurs, the molecule is polar. This is because a deflection on stream of liquid from the burette by a charged polythene rod indicates that the liquid consists of polar molecules. A polar molecule has a slight positive or negative charge and so when it is brought near to a charged rod it undergoes deflection. Errors and Improvements * We should take care not to touch the liquid with the polythene rod to make sure that deflection is not affected. * Any two compounds should not be kept close to one another as the vapours from one compound may affect the polarity of the other. * We should keep rubbing the polythene rod either to your hair or on a woollen cloth to make sure that it is charged. *