Lab 5 MW

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B. STANDARDIZATION OF A CALCIUM HYDROXIDE SOLUTION Write a balanced chemical equation for the reaction of hydrochloric acid with calcium hydroxide. Includes of reactants and products. Equation: 2HCI + cacoH) cac12+2H20 Data and Results: Molarity of hydrochloric acid Volume of hydrochloric acid Initial buret reading Final buret reading Trial 1 0.025 20.9. 2020L Volume calcium hydroxide used Moles hydrochloric acid used Moles calcium hydroxide used Concentration of calcium hydroxide Average concentration of calcium hydroxide Calculations: Trial 2 1000 mL 1.00 mL 060299 1000mL 0.30mL 19.00 mL mL mL L L 0 moles moles moles moles M M M 0.01000LHC (0.051800/241) = 0.000518300 1LHCl 0.000518HC (100/600) -0.000259 mol.com 2001 H M=0.000250 mol-0.0259M 0.01000 Experiment 21-A Review of Basic Laboratory Techniques

Write the balanced NET ionic equation for the reaction when aqueous Cs3PO4 and aqueous AgNO3 are mixed in solution to form solid Ag3PO4 and aqueous CSNO3. Be sure to include the proper phases for all species within the reaction.

The concentration of arsenic in an insectide is determined gravimetrically by precipitating MgNH4AsSO4 and isolating Mg2As2O7. Determine the %w/w Arsenic in a 1.500-g sample of insectide if it yields 0.1105g of Mg2As2O7. Solve using gravimetric calculation. Show the complete solution in a paper

Ammonium sulfate is added to an unknown mixture of ions. A precipitate forms. The solution is centrifuged, and the remaining solutions is decanted. Ammonium oxalate is then added to the solution and no precipitate forms. Sodium monohydrogen phosphate and sodium hydroxide are added to the decanted solution, and no precipitate forms. Sodium hydroxide is added to a fresh sample of the unknown. A damp piece of litmus paper over the opening of the test tube turns blue. Select the ions present.   Question 4 options:   Ba2+   Ca2+   Mg2+   NH41+

Ammonium sulfate is added to an unknown mixture of ions. A precipitate forms. The solution is centrifuged, and the remaining solutions is decanted. Ammonium oxalate is then added to the solution and no precipitate forms. Sodium monohydrogen phosphate and sodium hydroxide are added to the decanted solution, and no precipitate forms. Sodium hydroxide is added to a fresh sample of the unknown. A damp piece of litmus paper over the opening of the test tube remains red. Select the ions present.   Question 5 options:   Ba2+   Ca2+   Mg2+   NH41+

Gravimetric analysis of Fe3O4 (MW = 232 g/mole) may be undertaken with the following reactions:  Fe3O4 → Fe2O3 → Fe (OH)3. Weight of sample containing 8.00% Fe3O4 that must be taken to obtain a precipitate of Fe(OH)3 (MW = 107 g/mole) that weighs 150 mg is . a.  0.108 g  b. 0.325 g c. 1.355 g d. 4.065 g              Amount of Fe2O3 (MW = 160 g/mole) from which 150 mg of Fe(OH)3 (MW = 107 g/mole) may be obtained is .              a.  0.112 g              b.  0.224 g              c.  0.448 g              d. none of the other choices

Parts d. - g. on image part d. references part c.

In a lab, you diluted a sample of bleach to 1/10 concentration in a 250 vol. flask. Then quantitatively transferred into into a beaker and titrated it with a standard sodium thiosulfate solution with a molarity of 0.1215M. You repeated this 3 times. The data below is the amount of sodium thiosulfate that was titrated in the 3 runs. Calculate the molarity in each run of the diluted bleach and the concentration of undiluted bleach sample.

1. Calcium in a sample solution is determined by atomic absorption spectroscopy (AAS). A stock solution of calcium is prepared by dissolving 1.834 g CaCl, 2H,0 in water and diluting to 1 litre. From this stock solution, the second stock solution is prepared by the dilution factor of 10. Three standard solutions of calcium are prepared from the second stock solution with the following dilution factor: 20 (first standard solution), 10 (second standard solution) and 5 (third standard solution). A blank solution is prepared as well. Absorbance signals of AAS are as follows: 1.5 (blank solution), 10.6 (first standard solution), 20.1 (second standard solution), 38.5 (third standard solution), 29.6 (sample solution). (Molar mass; Ca = 40.00 g mol-, CI = 35.45 g mol-, 0 = 16.00 g mol-', H = 1.00 g mol-1) a. Construct ONE (1) plot that could be used to represent the calibration curve. b. From the plot of Q1a, determine the amount of calcium in parts per million.

A 600.0 mg sample consist only of CaC2O4 and MgC2O4 was heated at 500°C converting the two salts to CaCO3 and MgCO3. The resulting precipitate weighed 465.0 mg. If the sample had been heated at 900°C, the products would be CaO and MgO, what would the mixture of oxides weigh? (FW: CaC2O4=128.1; MgC2O4=112.3; CaCO3=100.1; MgCO3=84.31; CaO=56.08; MgO=40.31)

What is the easiest process to get to the result?

Solution and explanation for Percentage Yield and Theoritical Yield for this data (Synthesis of Aspirin) Salicylic acid - 1.950 g Labeled watch glass - 50.664 g Labeled watch glass & piece of filter paper together - 50.872 g filter paper only - 0.208 g Where the data is from: https://youtu.be/tLXljLxRZ0U Room temperature - filter paper, watch glass and aspirin - 53.088 g

8. A 2.856-g sample of limestone was analyzed for Fe, Ca, and Mg. The iron was determined as Fe;Os, yielding 0.04561 g. Calcium was isolated as CaSO4, yielding a precipitate of 1.487 g, and Mg was isolated as 0.1599 g of Mg;P2O7. Report the amount of Fe, Ca, and Mg in the limestone sample as %w/w FeO, %w/w CaO, and %w/w MgO.

A 0.2500-g of dry CaCO3  was completely dissolved into a solution of 5-mL conc. HCl and 50-mL distilled water in an erlemeyer flask. The resulting solution was boiled for 5 minutes to expel CO2 from the reaction, and then it was cooled to room temperature and the solution was transferred in a 500-mL volumetric flask filled to volume by rinsing the erlenmeyer flask and combining all the washings to fill the mark. A 5.0-mL aliquot of the CaCl2 solution was taken from the orignal solution and was transferred into an erlenmeyer flask with 10-mL NH3 buffer, 20-mL distilled water, and 5 gtts of EBT. The solution consumed 4.96 mL of an EDTA solution. MW: CaCO3 = 100.1   Compute for the N EDTA solution.         0.0053 N         0.0531 N         0.5313 N         None of the choices

- Calculate the concerntration of NaOH in the solution provided.

Dilution is necessary for commercially available acids such as HNO3, H2SO4 etc so that the strength is reduced to be used by students in a chemistry laboratory. Select one: O True O False

2. The formation of insoluble MgNH,PO,-6H,0, which is ignited to Mg.P.O, for weighing, can be used for the determination of Mg, N, or P. Write appropriate gravimetric factor that would apply to each determination.

Dilution is done to commercially available acids such as HNO3, H,SO4 etc so that the strength is increased and so it will be safe to be used by students in a chemistry laboratory. Select one: O True O False

1. A 1.2040 g sample containing sodium carbonate and inert material was dissolved in water and titrated to methyl orange end point, requiring 32.50 mL of 0.1020 M HCl. Calculate the %Na2CO4 in the sample. a. 93.36% b. 14.59% c. 12.75% d. 23.41%2. A 0.1510 g KHP (MW = 204.22 g/mol) sample required a volume of 57.04 mL of NaOH solution to reach a phenolphthalein end point. Calculate the molarity of NaOH titrant. a. 0.02593 M b. 0.006481 M c. 0.01296 M d. 0.01012 M

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Please answer all parts of section a and b. Thank you

A sample of processed meat scrap weighing 4.000 g is digested with concentrated H.SO. and Hg(catalyst) unti the Npresent has been converted to NHHSO.. This is treated with excess NaOH, and the liberated NHs is caught in a 100-ml of H.SO. ( Iml = 0.01860 g Na:OJ. The excess acid requires 57.60 ml of NaOH ( Iml = 0.12660 g potassium acid phthalate, KHCaH.O.j. Calculate the percentage protein in the meat scrap

A solid sample contains unknown amounts of potassium and magnesium chloride and moisture. 1.193 g of the sample is dissolved in water and the solution is diluted to 250.00 mL. 25.0 mL of the sample is allowed to pass through an H + -saturated cation exchanger, the eluate consuming 22.03 mL of a 0.100 M NaOH solution. The moisture content of the sample was determined to be 5.22%. Calculate the % by weight of potassium and magnesium chloride in the sample.

Questions 15-21 concern the reaction 2 SO2(8) + 102(8) 22 SO3(g), the crucial step in the production of sulfuric acid. For this reaction AH° = -198 kJ/mol and AS° = -0.187 kJ/mol·K. SO2 (perhaps from the production of copper metal) is mixed with air and heated, resulting in the formation of SO3. (All concentrations are in Kolks units.)