Lab Report I

Determining the Stoichiometry of Chemical Reactions Mrs. Farrales Nikita Pandya October 23, 2012 December 3, 2012 INRODUCTION In the rule of continuous variations the total emergence of bulwarks of reactants is kept constant for the series of measurements. severally measurement is made with a different mole ratio of reactants. A mole ratio is ratio betwixt the amounts in moles of whatever ii compounds involved in a chemical substance substance reaction.Mole ratios be used as conversion factors between products and reactants in many chemistry problems. The optimal ratio, which is the stoichiometric ratio in the equation, form the grea exam amount of product, and, if the reaction is exothermic, fork up the most heat and maximum temperature change, Double replacement reactions are more often than non considered to be irreversible. The geological formation of an insoluble fall provides a driving compact that makes the reaction proceed in maven direction only.In a image reaction, the two reactants which are aqueous solutions (which raft be broken down), put forward form two products one also an aqueous solution, and other which can be a hasty, water, or a gas, which cannot be broken down, whence making the reaction irreversible. The objective/goal of this laboratory is to find the optimum mole ratio for the formation of a precipitate in a double replacement reaction and use this information to predict the chemical formula of the precipitate. How can the products of a double reaction be predicted?How pull up stakes it be determined if a product is aqueous or a precipitate? How will the method of continuous variations help determine the mole ratio of the two reactants? METHODS Materials 1. Copper (II) chloride solution, CuCl2, 0. 05 M, 210 mL 2. Iron (III) nitrate solution, Fe(NO3) 3, 0. 1 M. 110 mL 3. atomic number 11 hydroxide solution, NaOH, 0. 1 M, 320 mL 4. Sodium phosphate, tribasic, solution, Na3PO4, 0. 05 M, 210 ml 5. (14+) Test vacuu m tubes (some graduate, some without graduations) 6. Black Marker 7. Marking put down 8. (2) Stirring rods, large 9. Pipets 10. (2) Test tube racks 1. (2) Pairs of gloves 12. scrutinying ground goggles 13. Lab apron 14. Timer 15. Para film Procedure The lab was get along up, as it is seen in figure 1, with septet runnel tubes in a streamlet tube rack. Using a clean 10mL graduated cylinder, the inhibit volume of iron(III) nitrate solution was taken from its container and transferred/added to from each one mental render tube using a pipet. Using a another clean 10mL graduated cylinder, the appropriate volume of sodium hydroxide solution was taken from its container and transferred/added to each block out tube, which already contained iron(III) nitrate, using a pipet.Before the metrer was started, each of the solutions in the test tube was stirred/mixed with a large inhalation rod. This ensured that both the reactants mixed properly. After stirring the solutions, observa tions were noted for any signs of chemical changes. The mixtures were to be left for 10 transactions (a quantifyr was used) to sit placid, because any movement of the test tube could cause a hindrance in the settlement of the precipitate. Though each test tube was left composed for 10 minutes, final observations were made after the solutions were left to sit undisturbed for 24 hours.After the 24 hours of settling, the volume of the precipitate in each test tube was measured and recorded. For test tube with graduations, seeing the numbers at eye level made the calculations, but for test tubes with no graduations a different method was used to measure the volume of the precipitate. First another test tube of the same size was found, so using a pipet, 1ml of water was measured in a 10mL graduated cylinder, and then poured into the equivalent size test tube. Using a black marker graduations were write on the test tube. Graduations up to 5mL only were made.After the graduations we re complete the graduated test tube was held side by side with the similar size test tube with no graduations, and the precipitate was measured using this method. The same procedures were recurrent with the reactants of the second table, CuCl2 and Na3PO4 Figure 1 The set up of the lab, the test tubes were label 1-7 RESULTS Data Table 1 balance between Fe(NO3)3 and NaOH are presented in this table along with the amount of precipitate that was produced in each of the test tube. Test Tube 1 2 3 4 5 6 7 Fe(NO3)3, 0. 1M, mL 1 2 4 3 2 5 4NaOH, 0. 1M, mL 11 10 16 9 5 10 6 FeOH Mole Ratio 111 15 14 13 25 12 23 Volume of devolve (mL) 1 mL 2. 8 mL 3 mL 0 mL 0 mL 0 mL 0 mL Data Table 2 Ratio between CuCl2 and Na3PO4 are presented in this table along with the amount of precipitate that was produced in each of the test tube. Test Tube 1 2 3 4 5 6 7 CuCl2, 0. 05 M, mL 1 4 4 6 6 8 5 Na3PO4, 0. 05 M, mL 5 8 6 6 4 4 1 CuPO4 Mole Ratio 15 12 23 11 32 21 51 Volume of set up (mL) 1 mL 4 mL 3. 75 mL 4 mL 2. 5 mL 3. 2 mL 1 mLRESULTS PARAGRAPH POST laboratory QUESTIONS Observations Fe(NO3)3 and NaOH 1. get rolling while 1207 uncaring instantly. After 3 minutes separated halfway closing curtain cartridge clip 1217 precipitate is 1/5 of test tube discolour is elation orangishness 24 hours by and by Same results 2. split up time 1211 Separated a midget End time 1221 The precipitate takes up 2/5 of the test tube & is orange 24 hours later Same results 3. Start time 1215 Instant time interval End time 1225 fluent still a little cloudy. devolve is ? of test tube color is light/dark orange 24 hours later Same results 4.Start time 1219 Separating VERY slowly End time 1229 at that place is no precipitate bonnie yet. Very cloudy. 24 hours later Same results 5. Start time 1222 interval did not occur instantly End time 1232 There is no precipitate just yet. Very cloudy. 24 hours later Same results 6. Start time 1224 Separation did not occur instantly End time 1234 T here is no precipitate. Very Cloudy. 24 hours later Same results 7. Start time 1227 Separation did not occur instantly End time 1237 There is no precipitate just yet. 24 hours later Same results CuCl2 and Na3PO4 1.Start time 1236 Separated quickly End time 1246 pass ? of test tube. Color is light sour 24 hours later Same results 2. Start time 1237 Separated quickly End time 1247 Precipitate is ? of test tube. Color is regular relentless 24 hours later Same results 3. Start time 1239 Separated quickly End time 1249 Precipitate is ? of test tube. Color is regular savoury. 24 hours later Same results 4. Start time 1241 Separated only a little bit in the inaugural two minutes End time 1251 Precipitate is ? of test tube and color is light mordant 24 hours later Same results 5.Start time 1242 Separated only a little bit in the prototypicborn two minutes End time 1252 Precipitate is 2/5 of test tube and color is light blue 24 hours later Same results 6. Start time 1243 Separated on ly a little bit in the first two minutes End time 1253 Precipitate is 3/5 of test tube and color is light blue 24 hours later Same results 7. Start time 1245 Separated only a little bit in the first two minutes End time 1255 Precipitate is 1/5 of test tube and color is light blue In the observations mentioned above, estimates using numbers (fractions) were made.These fractions basically estimate the amount of precipitate that was formed in each test tube, or the lack of a precipitate. Observations were made after the ten-minute mark, and then left under the fume goon for 24hrs due to the fact that time fell short observations were made then also. The observations also display that in the test tube where it was recorded that the separation between the compounds was instant, there was a precipitate formed. Respectively the observations also show that in test tubes where it was recorded that separation between the compounds was not instant, there was no precipitate formed.These observ ations describe the color of the solution/precipitate, and tell the transparentness of the solution. Lastly these observations elaborate on the slow or fast demonstrate of how each solution separated into a precipitate, or didnt, based on their specific mole ratio. It justifies how the different mole ratio produced the different precipitate amount. Figure 2 Fe(NO3)3 and NaOHFigure 3 CuCl2 and Na3PO4 These pictures show a visual of the seven test tubes in each investigate. In some of them the precipitates are present, in other test tubes there are no precipitates present, which means that they are still solutions.The test tubes with graduations, that had precipitates present were measured by reading the number at eye level. But test tube with no graduations, that had precipitates present, a special method that was mentioned in the procedures were used. Since in experiment two, all of the test tubes had a precipitate present there was a clear greenback in colors, the blue and clea r, they were heterogonous mixtures. But in experiment one, only triad of the seven test tubes had precipitates present, in those three test tubes there is a distinction in color, the red-ish orange and clear, they were heterogonous mixtures.But in the other four test tubes, since they are solutions it is a homogenous mixture where the entire solution has one consistency and color. parole By conducting the experiment, and analyzing the results, the optimum mole ratio for the formation of the precipitate in a double replacement reaction was found, and the chemical formula of the precipitate was found, the initial purpose of the experiment. At the beginning of the experiment two questions were proposed. ANSWER QUESTIONS ERRORS CONCLUSION LITTLE BIT FROM DATA AND DISCUSSION PARAGRAPH.