Pb (NO3) 2 10. A compound is 42.3 % C, 5.94 % H, 32.9 % N, and 18.8 % O and has a molecular mass of 425.25 g/mol. Calculate the empirical and molecular formula. C15H25N10O5 11. How many moles of Al2O3 are produced by the reaction 200. g Al?
Then multiply this by the molar mass of NaClO which has a label of g/mol so all labels cancel. Finally multiply by 100 to get a percent!) 6. The label on the commercial bleach reports the percent by mass NaClO to be 6.0%. Calculate the percent error of your value, assuming that the
Calculate the Normality of the vinegar using the previously given equation. Na = (Nb)(Volumeb) (Volumea) C. Calculate the mass of the acetic acid in grams using the previously given equation. Massa = (Na)(GMWa) D. Calculate the percentage of acetic acid using the previously given equation. % Acid = Massa(g/L) x 100 1000g/L Discussion and Conclusion: Questions: LabPaq question guidelines: Answer questions A and G in the lab manual. Skip questions B, C, D, E and F in the lab manual, and answer these instead: A.
0.05mol/6M=8.3*10-3 L=8.3mL stock solution c. 100mL-8.3mL=91.7mLwater Add 91.7 water to 6M stock solution to prepare 0.5M acetic acid. Exercise 8: a. 42.35 - 0.55 = 41.8 mL b. The moles of EDTA4- : 0.0189M*(41.8*10-3)L=7.9*10-4mol c. Zn2+(aq)+EDTA4-(aq)—Zn(EDTA)2-(aq) The ratio Zn2+ and EDTA4- is 1:1 The moles of Zn2+= the moles of EDTA4-=7.9*10-4mol d. 7.9*10-4mol*65.39g/mol=0.0517g Zn e.
Silver nitrate tested for 2o and 3o alkyl halides expected in dibromocholesterol and sulfuric acid tested for alkenes expected in cholesterol. Bromination had 68.8% yield, debromination 73.7% yield, and overall 53.3% of commercial cholesterol was recovered as synthesized cholesterol. For commercial cholesterol, dibromocholesterol, and synthesized cholesterol, melting points were 145.2-148.1oC, 109.0-110.1oC, 146.3-148.2oC and retention factor (Rf) values were 0.69, 0.80 respectively. Chemical tests confirmed expectations, though some alkenes were present in dibromocholesterol. The similar melting points of the synthesized product as compared to the literature value; and similar Rf values for commercial and synthesized cholesterol showed the purity of
9) The number of moles of H2CO3 in the reaction NaHCO3 + C2H4O2 NaC2H3O2 + H2CO3 is also the number of moles of NaHCO3. 10) Calculate the number of grams of sodium bicarbonate by multiplying the number of moles of sodium bicarbonate by its molar mass. OBSERVATIONS BEFORE REACTION Total Mass: 165.93 g Total Mass: 165.93 g Mass: Alka Seltzer Tablet: 3.82 g Beaker + Vinegar: 162.11 g Temperature: 20.9 °C DURING REACTION Observations: Alka Seltzer is fizzing and dissolving into the vinegar Gas is being released as bubbles form; it’s carbon dioxide Looks like a nice glass of frothy beer AFTER REACTION Observations:
Chromatography: Separating Mixtures Introduction: Magic marker inks are often mixtures of several compounds. Paper chromatography is a common method of separating various components of a mixture. After separation, you can observe the different colors that make up a particular color of magic marker ink. You can also calculate a ratio Rf, which compares how far each compound traveled to how far each solvent (substance that dissolves another substance) traveled during the experiment. Rf = Ds/Df Ds = Distance traveled by the compound Df = Distance traveled by the solvent Materials: coffee filter, tape, rubbing alcohol, water, 3 different color magic markers (not permanent); 3 identical tall, narrow drinking glasses; metric ruler, 3 pencils Pre-lab Questions: 1.
Experiment Title: Acid-Base Extraction: Separation of an Organic Acid, a Base and a Neutral Compound 1) -Mass of benzoic acid isolated = 0.893 g -Percent recovery of benzoic acid = 89.3% -Melting point of benzoic acid = 121 °C – 122 °C -Mass of 4-chloroaniline isolated = 1.2 g -Percent recovery of 4-chloroaniline = 120% -Melting point of 4-chloroaniline = 53°C – 60 °C -Mass of naphthalene isolated = 1.36 g -Percent recovery of naphthalene = 136% -Melting point of naphthalene = 65 °C – 70 °C 2) The differences in the masses of the compounds before and after the experiment may include the possibility that the solids were not dried completely since the masses afterward were larger than 1 g for both 4-chloroaniline and naphthalene. The wet solids may have added more weight. One reason to explain a mass less than 1 g fro Benzoic acid may deal with the possibility that not all of the components of the solid was collected properly. There may have also been a problem with the way that the solids were weighed on the scale and this could account for the differences. 3) The reason for the fact that the solvent used in an extraction should have a low boiling point is so that the solvent itself can evaporate out of the mixture.
The reaction is a synthesis. The Kc for this reaction is Kc = 49.7 at 458oC [Answer: [H2] = [I2] = 1.2 × 10-2 M, [HI] = 8.6 × 10-2 M] 2. Iodine and bromine react to give iodine monobromide, IBr. What is the equilibrium composition of a mixture at 150oC that initially contained 0.0015 mol each of iodine and bromine in a 5.0 L vessel? The equilibrium constant Kc for this reaction at 150oC is 1.2 102.
CMY282 EXPERIMENT 5 ANSWER SHEET PARTIAL MOLAR VOLUMES Name: …………………………..……………… Student number: …………………………..…………….… Title: Abstract: Results 1. Volume calculations Temperature: ρw = (from Table 6-1) Table 6-2: Calculation of volumes of water and ethanol Xw XE Vw (cm3) VE (cm3) 1 0.8 2 0.6 3 0.4 4 0.2 2. Preparation of the liquid mixtures and calculation of their exact mol fractions Table 6-3: Calculation of the composition of the actual samples Empty Flask m0 (g) Flask + W mA*(g) Flask + W + E mB*(g) mA* - m0 mw (g) mB* - mA* mE (g) mw/Mw nw (mol) mE/ME nE (mol) nE/(nw+nE) XE Water - - - - - - - 0 1 2 3 4 Ethanol - - - - - - - 1 3. Determination of the volume of the pycnometer Mass of empty pycnometer: g Temperature of the waterbath: ____ C Mass of full pycnometer: g .̇. Mass of the water: g .̇.