среда, 10 апреля 2019 г.
Demonstrating Sulphuric acid is Dibasic Essay Example for Free
Demonstrating sulfuric sharp is Dibasic EssayChemistry Practical projectAimThe aim of my experiment is to demonstrate that sulphuric acid, H2SO4, is dibasic. Dibasic means that one counterspy of sulphuric acid can force out two jettys of hydrogen ions, H+ when it reacts in an aqueous solution. To demonstrate the dibasic nature of sulphuric acid, I shall do two experiments, one involving a tit symmetryn, the other a particle accelerator collection.PredicationIn my titration, I shall consume an acid with a base. Firstly, I go away titrate Hydrochloric biting against atomic function 11 hydrated oxide. The match chemical equation for this reception is as follows.HCl(aq) + NaOH(aq) NaCl(aq) + H20(l)Hydrochloric loony toons, HCl, is a monoprotic acid, meaning that it will release one henry ion, H+ when reacted in an aqueous solution. The molar ratio in this reaction is 11, and therefore 1 counterspy of enthalpy ions, H+, will be needed to react with 1 mole of Hydrox ide ions, OH-, to remains 1 mole of Water, H20. therefore, I predict that this will mean that an equal number of moles of Hydrochloric superman will be needed to neutralise the Sodium Hydroxide.I shall then titrate sulphuric panelling against Sodium Hydroxide, in comparison to Hydrochloric acidic. HCl is monoprotic, whereas H2SO4 is diprotic, and will therefore release doubled the amount of Hydrogen ions, H+. The reaction is as followsH2SO4 (aq)+2 NaOH(aq) Na2SO4(aq) +2H2O(l)To demonstrate that Sulphuric cutting is dibasic, and that it will release two Hydrogen ions, H+, I predict that only half(prenominal) the number of moles of H2SO4 will be needed to neutralise one mole of NaOH. The molar ratio of acid to alkali is now 12, so for either Hydroxide ion released from the Sodium Hydroxide, two Hydrogen ions will be released from the sulphuric Acid, and so only 0.5 mole H2SO4 will be needed to neutralise 1 mole NaOH.For the atom smasher collection experiment, I shall again react firstly a monoprotic acid, then a diprotic acid and compare the amounts of gas collected. My first reaction will be mingled with Hydrochloric Acid (monoprotic) with magnesium Carbonate.2HCl(aq) + MgCO3(s) MgCl2(aq) + H2O(l) + CO2(g)My second reaction will be between Sulphuric Acid (diprotic), and Magnesium Carbonate.H2SO4(aq) + MgCO3(s) MgSO4(aq) + H2O(l) + CO2(g)For both(prenominal) reactions I shall collect the gas in a gas syringe, and compare the amounts of gas released. When surface reacts with acid, carbon dioxide is released. I will af charming acids of equal molarity, and the homogeneous hatful of magnesium carbonate. I predict that the H2SO4 will produce twice the tidy sum of gas in comparison to HCl, as this will demonstrate the dibasity of Sulphuric Acid.SafetySulphuric Acid is corrosive and therefore look must we worn at all times. If spillages occur, these should be washed liberally with cold body of water. Sulphuric Acid can burn skin and eyes, so lab coats and gloves should be worn. In case of contact with eyes, today flush eyes with plenty of water for at least 15 minutes. If sw pass oned drink plenty of water and seek medical help. Also follow standard laboratory safety such as removing retreat clothing and tying hair away from face.Fair TestTitration to hear a fair rivulet in my titration, I will use the same amounts of acid the same in severally titration, and pecker the variation in alkali needed to neutralise the acid. I will use a pipet and burette because they are the most exact equipment available, being accurate to +/- 0.05cm3. Before filling the burette and pipette I shall rinse them first with distilled water and then with the chemical to be used. This will allow me to sire more accurate readings from the equipment and reduce the assertable error margin. I shall rinse the burette and pipette likewise with the solution to be used to check up on no dilutions in my experiment, which could lead to inaccura cy.Gas Collection to ensure a fair test in the gas collection, I shall use equal jalopyes of Magnesium Carbonate in both collections, and bankers bill the varying amount of Carbon Dioxide released. I will use a gas syringe to collect the carbon dioxide because I think that this I more accurate than upwards delivery carbon dioxide is soluble in water and this could affect my results.For both experiments, I shall in like manner use the largest values possible as this will reduce the percentage error in my realistic to give me more reliable results.Titration MethodApparatus Sodium Hydroxide (1.0 molar), Sulphuric Acid (1.0 molar), Hydrochloric Acid (1.0 molar), 50 cm 3 pipette, burette, phenolphthalein indicator, white tile, clamp stand, boss, distilled water dispensers, pipette filler, 4 100cm3 beakers, 2 100cm3 conelike flaskfuls, plastic filter funnel.Perform pre-tests to determine the colour change of the indicator at the end shoot of the titration and the colour of pheno lphthalein in acids and alkalis.Prepare the equipment as followsBurette rinse with distilled water followed by the solution to be used, NaOH as not to dilute the solution with water. fade solution through and invert the burette to ensure no air bubbles.Fill the burette with NaOH using a filter funnel, and remove the funnel. Record the flock of solution within the burette to 0.05 ml.Pipette rinse the pipette several times by imbibe and releasing the solution to be used, HCl or H2SO4, using a pipette filler, (suck up solution to preceding(prenominal) the measured mark)Using pipette filler, fill pipette with until the meniscus is slightly above the mark.Take the pipette bring out of the solution to ensure no atmospheric pressure and allow the liquid to run out slowly until the meniscus is level with the mark.Touch the side of the flask with the tip of the pipette but allow any residue to remain in the pipette.Add 3-4 drops of the indicator phenolphthalein to the solution in the c onical flask (no more as indicators are weak acids and so can have an effect on the titration) drill a white tile to help identify the colour change at the end point.Run the solution from the burette whilst swirling, stop as soon as the indicator colour changes.Record the leger of the rough titration. twin the titration carefully and drop wise until the colour is about to change, then add half a drop at a time.When the faintest detectable colour change can be noted, interpret the final volume to within 0.05 ml. reduplicate the titration to get three accurate titrations within 0.1 ml of each other.Gas CollectionApparatus Hydrochloric Acid (1 molar), Sulphuric Acid (1 molar), Magnesium Carbonate, 6 conical flasks, gas valves and bungs, gas syringe with delivery tube, Clamp stand and boss.Set up the experiment as shown. controvert 0.34g MgCO3 with 100ml HCl for at least 10 minutes or until the reaction is complete.Record the volume of CO2 produced.Repeat three times, ensuring that th e gas syringe is always set at zero before the experiment is set.Repeat with H2SO4to allow the comparison of results.QuantitiesTitrationFrom my research I know that the maximum volume of Sodium Hydroxide will be needed in the titration with Hydrochloric Acid. The burette I will be using can measure accurately up to 50cm3. I from my calculations, this amount will be used to neutralise 50cm3 of acid. For the reaction with Sulphuric Acid, twice the volume of NaOH shall be needed to neutralise the acid. Therefore, I shall use only 25cm3 acid for both titrations, as I know that 50cm3 NaOH is the maximum volume I will need. The advantage of using the largest volumes possible is that the percentage error is reduced, and my experiments will therefore me more accurate.Gas CollectionH2SO4(aq) + MgCO3(s) MgSO4(aq) + H2O(l) + CO2(g)This is the reaction that I predicted would release the most carbon dioxide. I therefore had to work out what the maximum amount of product I could use within the p ractical limits of my apparatus.Max volume gas released 100cm3No. moles = echt volume 24= (1001000) 24= 0.004 moles CO2Molar ratio MgCO3 CO2 =11Therefore 0.004 moles MgCO3Mr MgCO3 = 24+12+ (16 x 3)=84Actual Mass = number of moles x mass 1 mole= 0.004 x 840.34g Magnesium Carbonate to be used.The Sulphuric Acid must also be amaze in excess to ensure the reaction goes to completion, and so I will therefore use 0.1 mole H2SO4.Volume = number of moles concentration= 0.01 1 = 0.01 dm-3, or 100 cm-32HCl(aq) + MgCO3(s) MgCl2(aq) + H2O(l) + CO2(g)For my second reaction, I shall use the same mass of Magnesium Carbonate, and provided the acid is still in excess, the same volume of Hydrochloric Acid, to ensure a fair test.Mass MgCO3 to be used = 0.34gMolar ratio HCl CO2 = 21Therefore 0.004 x 2 moles HCl to be used.To allow the acid to be present in excess, I shall use 0.01 mole of Hydrochloric Acid.Therefore, volume = number of moles x concentration=0.01 1=100cm3Specimen CalculationsTit ration using Sodium Hydroxide and Hydrochloric AcidHCl(aq) + NaOH(aq) NaCl(aq) + H20(l)Volume HCl used 25 ml or 0.025 dm-3 twist of moles HCl = concentration (mol dm-3) volume (dm-3)= 1m 0.025 dm-3= 0.025 moles HClMolar ratio NaOH HCl = 1 1Therefore 0.0251= 0.025 moles NaOHVolume NaOH = number of moles concentration (mol dm-3)= 0.025 1=0.025 dm-3This shows that an equal volume of Sodium Hydroxide is needed to neutralise the Hydrochloric acid, indicating that for every OH- ion in the NaOH, one H+ ion was released from the Hydrochloric Acid to form H2O, a neutral molecule. This shows that Hydrochloric Acid is monoprotic, as it releases one Hydrogen ion when it is reacted in an aqueous solution.Titration using Sodium Hydroxide and Sulphuric AcidH2SO4 (aq)+2 NaOH(aq) Na2SO4(aq) +2H2O(l)Volume H2SO4 used 25 ml or 0.025 dm-3Number of moles H2SO4 = concentration (mol dm-3) volume (dm-3)= 1m 0.025 dm-3= 0.025 moles H2SO4Molar ration NaOH H2SO4 = 2 1Therefore 0.0252 = 0.0125 moles NaOHVo lume NaOH = number of moles concentration (mol dm-3)=0.0125 1 = 0.0125 dm-3This shows that only half the volume of Sodium Hydroxide was needed to neutralise the Sulphuric Acid, indicating that for every OH- ion in the NaOH, two H+ were released from the Sulphuric Acid, demonstrating its dibasity, as for every mole of Sulphuric Acid reacting in solution two moles of Hydrogen ions were released.Gas Collection2HCl(aq) + MgCO3(s) MgCl2(aq) + H2O(l) + CO2(g)Number of moles MgCO3 = actual mass mass 1 moleMr MgCO3 = 84= 0.34 84= 0.004 molesMolar ration HCl CO2 = 2 1Therefore 0.004 2 = 0.002 moles CO2Volume = number of moles x 24= 0.002 24= 0.048 dm-3 or 48cm3H2SO4(aq) + MgCO3(s) MgSO4(aq) + H2O(l) + CO2(g)Number of moles MgCO3 = actual mass mass 1 moleMr MgCO3 = 84= 0.34 84= 0.004 molesMolar ratio H2SO4 CO2 = 1 1Therefore 0.004 moles CO2Volume = number of moles 24= 0.004 24=0.096 dm-3 or 96cm3When a metal carbonate reacts with acid, carbon dioxide is released. These results show that when Magnesium Carbonate reacts with Sulphuric Acid, twice the volume of Carbon Dioxide is produced in comparison to its reaction with Hydrochloric Acid. This shows that, as we know HCl to be a monobasic acid, Sulphuric Acid is dibasic, as it produced double the volume of gas as a result of its two Hyrdogen ions that are released.BibliographyChemistry Chris Conoley and Phil Hills (p. 332)Collins educational 1998Steven Doherty Atoms, Molecules and Stoichiometrywww.catalogue.fisher.co.uk/scriptsCambridge University Press 2000Chemistry Brian Ratcliff