Note that the weight of your sample is expected to decrease by at least 30 % of its original mass (~ 0.3 g). The bottom of the crucible should be heated to a dull red color during this period Grasp the crucible just below the cover with the concave part of the tongs and very care fully transfer it to a Ceramfab pad. 3. 3.The mass of the crucible, cover and KClO3 was measured. To do this, you will need three test tubes. Composition of Potassium Chlorate A. Be aware that silver nitrate may stain the skin and nitric acid may burn the skin. Why? Specifically, the residue will be tested for the presence of chloride ions by the addition of nitric acid and aqueous silver nitrate. 2 ⎛ ⎝ ⎜⎜ ⎞ ⎠ ⎟⎟ * 2 mol KClO. This can be theoretically calculated using atomic masses found on the periodic table, and experimentally calculated from lab data. Add approximately 1 gram of potassium chlorate to the crucible. Be sure to show all steps and work in the space provided. to write your report Experiment 6: Percent Composition, Lets begin writng the themical reactions that were carried out in this lab In Part A of this lab, potassium chlorate was Experiment 6 - ViDeX Percent Composition report writing_ Class play 17.1557 g. 19.5967 g. 18.5869 18.5848 DATA & CALCULATIONS Students can therefore evaluate their accuracy in this experiment by comparing their experimental results to the true theoretical value, and by calculating their percent error. Adopted a LibreTexts for your class? Dispose of the remaining contents in the crucible down the sink. Mass of crucible + cover + residue after and heating 24.5539 N/A 5. The percentage of each element is then calculated by dividing its total mass in the compound by the molar mass of the compound and multiplying by 100. LAB REPORT 5 1-Report-percent Composition of Potassium Chlorate in a mixture of potassium Chlorate and Potassium Chloride . Add some distilled water to your crucible and. Upon analysis of this mixture, would you obtain a larger or smaller mass percent of oxygen than you would for an equal mass of pure sample of potassium chlorate (circle one)? What will you observe if you obtain a positive test for chloride ions? Allow to cool (about 10 minutes and weigh. In this lab, students will test the percent composition of KClO3. A residue of potassium chloride will be left in the "container" after the heating is completed. Potassium chlorate will decompose into oxygen and potassium chloride. Purpose The mass percent of potassium chlorate in a mixture will be determined by its thermal decomposition and production of oxygen gas, which will be measured via displacement of water. In this case, the potassium chlorate is functioning as the oxidizer, while the sugar is the fuel. 2.KClO3 was added to the crucible. determine the mass of potassium chlorate present in the original mixture (this is the KClO. The potassium chlorate sample was not heated strongly or long enough. 3mol. 1 decade ago. Mass of crucible + cover + residue after 2^nd heating 5. In Part A of this lab, a sample of potassium chlorate will be experimentally analyzed in order to determine the mass percent of elemental oxygen present in it. Theoretical percent oxygen in KCIO, Show calculation setup 12. D O N OT O BLITERATE E RRORS. A. This Lab: Percent of Composition of KClO3 Lesson Plan is suitable for 9th - 12th Grade. Continue to use only distilled water for the rest of Part B. Fetch a stand and ring clamp from the back of the lab. 3 = α. g O. Cover the crucible with the lid. The compound that they are going to use in this experiment is KCl or potassium chlorate. 2. β. g O. λ. g KClO. Show your calculations clearly. Final mass of residue Show sample 1 calculation setup 9. This causes it to decompose into solid potassium chloride and oxygen gas. When potassium chlorate is heated to high temperatures (above 400°C) it decomposes to potassium chloride and elemental oxygen, according to the following equation: 2KCIO,(8) - 2 KCl(s) + 30(8) The relative amounts of oxygen and potassium chloride are measured by heating a weighed sample of potassium chlorate until all of the oxygen has been released from the sample. The proportion by mass of elements combines in potassium chlorate varies 3. Get a verified expert to help you with Decomposition of Sodium Chlorate Lab. 2.KClO3 was added to the crucible. In Part A of this lab, you will analyze a sample of potassium chlorate to determine the mass percent of oxygen present in it. How long must the sample be heated the second time? λ, below, in the equation.) Determine the percentage of potassium chlorate in the original white mixture using your answers from step 6 (the pure KClO3) and step 2 (the mass of the original mixture.) In this experiment, potassium chlorate will be used instead of sodium chloratethe employed commercially (see Figure 1). Using the top-loading balance, pre-weigh about 2.5 – 3.0 g of pure KClO3 into a plastic weighing boat. Was your average experimental mass percent of oxygen in potassium chlorate higher or lower than the theoretical value (circle one)? THE DECOMPOSITION OF POTASSIUM CHLORATE . Record your data in your lab notebook. Potassium chlorate will decompose into oxygen and potassium chloride. 2 ⎛ ⎝ ⎜⎜ ⎞ ⎠ ⎟⎟ * δ. g KClO. Now add distilled water to the crucible containing the residue from the first sample so it is one-half full. Privacy Then weigh and record the mass of the crucible, lid, plus the residue that remains. Begin analy sis of a second sample while the first is cooling, After weighing reheat the first sample for an additional 6 minutes at the maximum flame temperature (bottom of the crucible heated to a dull red color, cool and reweigh. Date Performed: July 30, 2012 EXPERIMENT NO. Mass of original sample Show sample 1 calculation setup: 7. Conclusion: In this lab, the decomposition of potassium chlorate was used to find the mass percentage of oxygen in potassium chlorate. Pre-Lab Assignment Before coming to lab: • Read the lab thoroughly. & Heat the potassium chlorate sample slowly to avoid any splattering. Record what you observed when silver nitrate was added to the following: (a) Potassium chloride solution formed a white precipitate (b) Potassium chlorate solution formed a cloudy white solution (e) Residue solution formed a white precipitate 2. 1 and a like amount of potassium chlorate into tube No. If the mass decreased more than 0.05 g between these two weighings, repeat the heating and weighing until two successive weighings agree within 0.05 g. Use the final weight in your calculations Complete the analysis of the second sample following the same procedure used for the first B. Qualitative Examination of Residue This part of the experiment should be started as soon as the final heating and weighing of the first sample is completed and while the second sample is in progress. Mass of crucible + cover + residue after 1 heating 24. QUESTIONS AND PROBLEMS 1. Record the mass of the ... Potassium chlorate is a strong oxidizing agent. SOX 4. (the molar mass of potassium chlorate) to . λ g KClO 3 = α g O 2 (lost) * mol O 2 βg O 2 ⎛ ⎝ ⎜⎜ ⎞ ⎠ ⎟⎟* 2 mol KClO 3 3mol 2 ⎛ ⎝ ⎜⎜ ⎞ ⎠ ⎟⎟* δ g KClO 3 1molKCO 3 ⎛ ⎝ ⎜⎜ ⎞ ⎠ ⎟⎟ Page I-32 / Percent Potassium Chlorate in a Mixture Place three medium-sized test tubes in the test tube rack. The potassium chlorate sample will be heated in a specialized "container". Do you expect it weigh more than, less than or the same as the original potassium chlorate sample? It … Potassium chlorate is composed of 5 elements Can you tell me which is the answer … Answer--> potassium chlorate: 67. Be careful not to introduce any foreign material into the bottles of potassium chlorate since The percent composition is calculated by © 2003-2021 Chegg Inc. All rights reserved. Are there any other observations that you have made during this experiment (not those in the table above) that would suggest that the potassium chlorate was converted to a new substance upon heating? Use your data to determine the experimental mass percent of oxygen in \(\ce{KClO3}\). To do this, the potassium chlorate must be heated to temperatures greater 400 °C, causing it to thermally decompose into potassium chloride and free oxygen: \[\ce{2KClO3 (s) ->[heat] 2KCl(s) + 3O2 (g)}\], \[\text{Potassium Chlorate} \ce{->} \text{Potassium Chloride} + \text{Oxygen}\]. In this laboratory exercise you will decompose this compound by heating, and from the data obtained determine the percentage of oxygen by … The test tubes should be thoroughly cleaned and rinsed with distilled water. In this experiment, solid potassium chlorate will be strongly heated. Experimental percent KCl in sample (KC103) Show sample 1 calculation setup: 11. 1.97 g – 1.23 g = 0.74 g. experimental percentage of oxygen in KClO3: mass of oxygen driven off___ x 100 = experimental percentage of oxygen in mass of potassium chlorate used KClO 3. Explain how your observations in the table above verify that the residue in your crucible after heating is potassium chloride. NOTE The crucible must be covered when potassium chlorate is being heated in it. Repeat all steps for your second crucible and second sample of potassium chlorate. How long must the sample be heated the first time (total)? 122.55 g/mol. This procedure using nitric acid and silver nitrate is a general test for chloride ions. Explain your answer? Suppose you are provided with a 36.55 g sample of potassium chlorate. Solid potassium chlorate (\(\ce{KClO3}\)), solid potassium chloride (\(\ce{KCl}\)), 6M nitric acid (\(\ce{HNO3}\)), 0.1M silver nitrate (\(\ce{AgNO3}\)), two crucibles with lids, stand and ring clamp, clay triangle, crucible tongs, Bunsen burner, three medium-sized test tubes, test tube rack, stirring rod, and an electronic balance. 3; add about 10 mL of distilled water and mix. 1. the proportion by mass of elements combines in potassium chlorate is fixed 2. Procedure: 1.The mass of the crucible and the cover was measured. DISCUSSION The percentage composition of a compound is the percentage by mass of each element in the compound. If the sample loses more than 0.05 g after the second heating it has not been heated to constant weight and should be heated a third time. Add approximately 1 gram of potassium chlorate to the crucible. This is accomplished when the sample is heated to constant weight. Answer In-Lab Questions #3 and #4. Be sure to carry the proper number of signi fi cant fi gures in your computations. For the first 6 minutes, the sample should be, For the last 6 minutes, the sample should be. In this experiment, our % oxygen was lower than the actual % oxygen in the formula. Put a pea-sized quantity of potassium chlo- ride into tube No. Determining Percentage Composition Sample 1 Sample 2 1. The equation to use: 7. using your answers from step 6 (the pure KClO3) and step 2 (the mass of the original mixture.) 2. Mass of crucible + cover + residue after 3rd heating Gif necessary 6. The tip of the sharply defined inner blue cone of the flame should almost touch and heat the crucible bottom to redness. Explain your choice. Mass lost when sample was heated (Oxygen). In Part B of this lab, the residue left after heating will be qualitatively analyzed in order to demonstrate that it is chemically different from the initial potassium chlorate sample. 3.The mass of the crucible, cover and KClO3 was measured. In this experiment the percentage composition of potassium chlorate will be determined both experimentally and from the formula. 3. To calculate the percentage of oxygen in potassium chlorate, KClO3, theoretically and experimentally. In Part B of this lab, you will analyze the residue in left the "container" in order to experimentally verify its identity. Write the balanced formula equation for the rene tion to be expected when calcium chlorate, Ca(CIO), is heated. to write your report Experiment 6: Percent Composition, Lets begin writng the themical reactions that were carried out in this lab In Part A of this lab, potassium chlorate was Experiment 6 - ViDeX Percent Composition report writing_ Class play 17.1557 g. 19.5967 g. 18.5869 18.5848 DATA & CALCULATIONS Will this container be covered or uncovered while heating? Observations (after the addition of both nitric acid and silver nitrate). Be sure that the crucible is covered, and that that the top of the flame is touching the bottom of the crucible. The decomposition of potassium chlorate results in a solid potassium chloride and oxygen gas. Mass of crucible + cover + residue after 1^st heating 4. Solid potassium chlorate (\(\ce{KClO3}\)), solid potassium chloride (\(\ce{KCl}\)), 6M nitric acid (\(\ce{HNO3}\)), 0.1M silver nitrate (\(\ce{AgNO3}\)), two crucibles with lids, stand and ring clamp, clay triangle, crucible tongs, Bunsen burner, three medium-sized test tubes, test tube rack, stirring rod, and an electronic balance. 2. show 2 K, 2 Cl and 6 O on each side of the arrow. The molar mass of a compound is determined by adding up the atomic masses of all the atoms making up the formula. Show your work clearly. High schoolers find the percent of oxygen in potassium chlorate. ... Ph.D. 3. The only remedy that will be applied here wil l be the inclusion of the manganese (IV) oxide catalyst. 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