Part B: The graduated pipet’s average density at 22.3 °C was determined to be 0.9785g/mL with a percentage error of 1.89% shows the graduated pipet to be more accurate and precise. Part C: Density of an unknown NaCl solution was measured and a calibration curve used to determine the percentage of NaCl by mass in the solution. y=0.007x + 0.998 which concluded that the concentration of the sodium chloride solution was 3.14%. INTRODUCTION Anything that you can see, touch, taste or smell, occupies space and has mass, it is called matter. Matter can be a gas, a liquid,
Partner: Tyler Smith Data Table #1 Pure Solvent Mass of test tube + cork 45.502 g Mass of test tube, cork, + p-xylene 70.199 g Mass of p-xylene 24.697 g Data Table #2 Unknown Molecular Weight Determination Unknown letter C Mass of solid unknown 2.256 g Data Table #3 Results Freezing point of P-xylene, T°f 13.4 °C Freezing point of solution, Tf 10.8 °C Value for ΔTf 2.60°C Molality of unknown solution, m 0.60 m Mass of p-xylene, g 24.697 g Mass of p-xylene, kg 0.0247 kg Mols unknown solution 0.015 mols Mass of unknown added 2.256 g Molecular weight of unknown solute 1.5 x 10 2 g/mols 3. Show the calculation for obtaining the mass of p-xylene used in the experiment. (Mass of test tube, cork, + p-xylene ) - (Mass of test tube + cork) 70.199 g - 45.502 g = 24.697 g 4. Show the calculation for obtaining the mass of unknown added.
This experiment can only be carried out if the solubility rules are understood and a flame test result chart is available. Materials and Methods Part 1 To commence this part of the experiment, five labeled test tubes were filled with 10 drops of their corresponding cation solutions, K+, Fe3+, Zn2+, Cu2+ and Co2+. The colors of the solutions were recorded. Next, the metal hydroxide elimination test was carried out. No more than 20 drops of 6M NaOH were added dropwise to each solution until a precipitate was observed.
Results | | | | Trial #1 | Trial #2 | Volume of NaOH at equivalence point | 9.5 mL | 13.7 mL | Volume of NaOH at one-half the equivalence point | 4.75 mL | 6.9 mL | pH at half equivalence point | 5.42 | 5.3 | pKa of unknown acid | 5.42 | 5.3 | Average pKa | 5.36 | 5.36 | Average Ka | 4.4 * 10-6 | 4.4 * 10-6 | Moles of unknown acid | 1.30 * 10-3 moles | 1.87 * 10-3 moles | M of unknown acid | 0.0650 M | 0.0805 M | Average M of unknown acid | 0.07275 M | 0.07275 M | 2. The data table containing all your raw and manipulated data (like the one found on page 47 of your lab manual). Be sure to include your lab partner’s name and unknown number. Unknown acid buret | | | | Trial #1 | Trial #2 | Initial buret reading | 20.5 mL | 21.8 mL | Final buret reading | 40.5 mL | 45.1 mL | Volume of acid added | 20.0
Chem 1110 - Stoichiometry 1) A 25.00 mL aliquot of H3PO4 was titrated with 43.12 mL of 0.002548 M Ca(OH)2: 2H3PO4(aq) + 3Ca(OH)2(aq) → Ca3(PO4)2(s) + 6H2O(l) What was the concentration of the H3PO4 solution before titration? Express your answer in moles/L. [Ans. : 0.002930 M] 2) In one experiment, 22.9841 grams of 75.25% pure Pb(NO3)2 (pure Pb(NO3)2 has a molar mass of 331.2 grams) was mixed with 51.2354 grams of 81.21% pure CsI (pure CsI has a molar mass of 259.80992 grams): 2CsI(aq) + Pb(NO3)2(aq) → 2CsNO3(aq) + PbI2(s) After the reaction, 10.4025 grams of PbI2(s) (molar mass 461.0 grams) were collected. What is the percent yield of the reaction?
Shelby McLenithan Honors Chemistry 12/1/10 STOICIOMETRY LAB Question= which compound will produce the most CO2 by heating of the following: * Calcium carbonate * Sodium bicarbonate * Copper (II) carbonate. Hypothesis= Calcium carbonate will produce the most Co2 by heating Stoichiometry: Variables: Dependent= amount of CO2 Independent= the reactants control= amount of reaction, same amount of heating ( 5 minutes) Procedure: 1. Measure out 1 gram of CO2 2. Heat CaCO3 for 5 minutes using th Bunsen burner 3. Find mass of CaCO3 after 5 minutes 4.
The melting point ranges of the impure and pure benzoic acid seemed reasonable. The difference between the literature melting point values of the pure Benzoic acid 21.5-22.5 is different than the one determined in the experiment. The recrystallization was experimentally showed as an inaccurate purification method. Introduction: Recrystallization is the purification technique in which a solid slowly forms, crystallize, from a liquid solution. It is based on the manipulation of the solubility at various temperatures.
On the other hand, both mercury and alcohol were used for room temperature, and placed in one place for 5 minutes. Both thermometers had precise and accurate results for 3 trials. We verified if temperature is an intensive property of matter. We used water and cooking oil for their boiling point. Water with three different volumes (100mL, 200mL, and 300mL) was heated and each mass and boiling points were collected.
The graduated cylinder was placed on the scale again (with the added liquid) and the mass was measured in grams to the nearest .01 gram. The graduated cylinder was then placed on the tabletop and the volume was read to the nearest tenth of a milliliter. The liquid was then poured back into the beaker, and the graduated cylinder was thoroughly dried. At Lab Station 2, a dry 10mL graduated cylinder was placed on a balance and the mass was recorded in grams to the nearest .01 gram. Approximately 3mL of Clear Liquid 2 was carefully poured into the graduated cylinder.
In the first part, preparation of 5 x 10-3 m EDTA titrant was done by dissolving approximately 0.47 grams of EDTA in 250 ml distilled water. A pinch of MgCl2 • 6H2O was added. The solution served as the stock titrant. In the second part, preparation of diluted EDTA titrant was done. We took 10.00 ml aliquot of the prepared titrant and placed it in a 100.0 ml volumetric flask to dilute.