A high resolution thermal gravimetric analysis method is usually used as it has great accuracy this is because as the weigh of the sample increases the temperature is increase is slowed so that the exact temperature at which the weight is the highest can be accurately
Further experimentation with multiple trials could strengthen these results. Although some errors were made with the mineral solution from the filtration process, the percent error calculated for the mineral was partially accurate. The theoretical value of Cu2+was calculated to be 57.48%, while the experimental value was 50.6%. The percent error was was not below 5 percent, but it was below 20 percent, which is fairly good. This result supports that the methods used during this experiment are sound.
7. Empirical Formula for copper sulfide:Cu2S In order to determine the empirical formulas, the mass in grams is converted to moles. Average mass of copper: 1.24g Cu Average mass of sulfur: 0.28g S 1.24g Cu X 1 mol Cu/ 63.55g Cu = 0.0195mol Cu 0.28g S X 1 mol S/ 32.07g S = 0.0087mol S Then, to find the smallest whole number ratio, we divided each number of moles by the smallest number. The ratio is 2Cu:1S, so the empirical formula is Cu2S 0.0195mol Cu / 0.0087mol S= 2 0.0087mol S / 0.0087mol S = 1 8. Balanced chemical equation for the formation of copper sulfide from copper and sulfur.
The three trials reacted 27.95 mL, 26.61 mL, and 25.74 mL of potassium permanganate to determine 55.7%, 53.0%, and 51.3% respectively of oxalate in the compound with a 53.3% average. To calculate the empirical formula of the compound, the percent composition of the each piece of the compound needed to be found. A thermogravimetric analysis performed outside the lab determined 11.0% of the compound was water and an inductively coupled plasma atomic emission spectroscopy found 11.3% was iron. Potassium accounted for the remaining 24.4% of the compound. The compound’s empirical formula was determined to be FeK3(C2O4)3•3H2O.
Discussions. This method is used to accurately quantify pesticides in water samples. The lyophilization is advantageous to allow the complete of the samples to minimize error. The acetonitrile resulted in 82% - 104% extraction efficiency for Alachlor and Malathion in the water samples. The different solvent gradient was fixed to contain both the physical and chemical properties of the pesticides.
Morever, for measuring the density using hydrometer large sample volume is required. Conclusion In conclusion, almost our group reached main target. We used two different methods which were hydrometer and density bottle method in order to measure the density of water at different temperatures. We calculated the densities of water which were 995, 992.5, 991, 990 kg/m3 for the first part and 967 kg/m3 for the second part. Finally we compared these two methods in order to decide which method is more suitable.
What is the molecular formula of this hydrate? *Answers to questions above... 1) 4.078 + 4.056 + 4.095 + 4.014 = 16.24/4 = 4.061 ±0.008 grams 2.253 + 2.256 + 2.261 + 2.249 = 9.019/4 = 2.255 ±0.012 grams 2) Mass of water = 4.061 – 2.255 = 1.806 ±0.020 grams Then convert to moles =1.806 ±0.020 / 18 g = 0.100 ±0.020 mol H2O Covert to moles of copper Sulfate =2.255 ±0.012 / 159.6 = 0.0141 ±0.012 mol CuSO4 Finally simplify those values by dividing by the smallest number =0.0141 ±0.012 / 0.0141 ±0.012 = 1 Then: 0.100 ±0.020 /0.0141 ±0.012 = 8 3) Molecular Formula= CuSO4 x 8H2O
To then find the percent water divide the water mass by the hydrate mass and multiply by 100 since the number is a percent. The water percent is determined to be 42.06%. To find a percent error, a theoretical percent water must be used. To find the theoretical percent error divide the mass of water by the mass of magnesium sulfate heptahydrate and multiply by 100 to get a percent. The theoretical percent water is
First, 50 mL of the sample was placed into a 250 mL Erlenmeyer flask, and onto a stirring plate. Then, the pH of the solution was measured and adjusted to be within the range of 4 and 6, using nitric acid and sodium hydroxide. After the pH was optimal for the experiment, a single mL of indicator- acidifier reagent was added to the sample. Then, 50 mL of mercuric nitrate was place into a burette and titrated with the sample until the color of the solution turned from blue to purple. The volume of titrant used for the reaction to reach endpoint was recorded.
The blue colour of hydrate CuSO4 turns white at the end of the heating process. Base of the crucible becomes black, indicates that there is soot produced. Determine The Precision Of Data by Calculating Mean or average of the data, x ̅ =(total reading)/(number of reading) Mean, x ̅ (Mass of H₂O in the hydrated sample 1 g)