4 Discuss the process of sampling and preparation of laboratory sample in quantitative analysis.

Mass Spectrometry of Molecular Compounds Mass spectrometry is not only used for isotopic evaluation of the elements. It can also be used for identification of molecular samples as well. Consider, for example, the mass spectrum of pentane (Figure 5): Lifie relative abundance 57 29 72 10 20 30 40 50 60 70 miz Figure 5. Pentane Mass Spectrum The pentane molecule (CH;CH,CH;CH;CH; or C;H12) is a straight-chain hydrocarbon. In Figure 5, notice there are four groups of peaks. This forms what is known as the cracking pattern of the molecule. The first peak is at m/z = 72, corresponding to the molecular ion, C;H,2", where only one electron was knocked off the pentane molecule. The three peak groups are from fragments of pentane created in the ionizer: m/z = 57 (CH;CH,CH,CH,"), m/z = 43 (CH;CH,CH;"), m/z = 29 (CH;CH,"). These species have had pieces of the molecule knocked off in addition to losing an electron. 4. For the peak at m/z = 43, what part of the pentane molecule was knocked off? Use…

A 800.0 mL aqueous solution of 93.0 mM CoCl2 is combined with 399.0 mL of aqueous 54.0 mM K3PO4. If the limiting reagent is completed consumed during this reaction, how many grams of solid precipitate will be produced? Express your answer in units of grams using at least three significant figures.

5) King Krator the Merciless has called on Pogo, a humble goldsmith, to make a crown for theKing. He gives Pogo exactly 14 oz of pure gold to fashion the crown and tells him that if hecheats the King, he will pay with his life ! Pogo leaves with the gold; he and his apprenticesspend two weeks in making the crown; finally he returns to the court. When Pogo returns withthe crown, King Krator finds that the crown weighs 397.25 grams, and has a volume of20.58cm3. King Krator asks the court wizard for the density of gold, and Wizard tells the Kingthat gold has a density of 19.3 times that of an equal volume of spring rain. Krator demands aslate, makes a few calculations, then sternly lifts his head to stare at Pogo. Does Pogo's headroll ?

Thallium(I) sulfate is an active ingredient in rat poison. We can analyze a sample for the mass percentage for this active ingredient by adding potassium iodide to precipitate yellow thallium(I) iodide. If the sample of rat poison weighed  999.5 mg and you obtained  279.4 mg of the dry precipitate, then what is the mass percentage of the thallium(I) sulfate in the rat poison?

Combustion of hydrocarbons such as hexane (CH 14) produces carbon dioxide, a "greenhouse gas." Greenhouse gases in the Earth's atmosphere can trap the Sun's heat, raising the average temperature of the Earth. For this reason there has been a great deal of international discussion about whether to regulate the production of carbon dioxide. 1. Write a balanced chemical equation, including physical state symbols, for the combustion of liquid hexane into gaseous carbon dioxide and gaseous water. 2. Suppose 0.360 kg of hexane are burned in air at a pressure of exactly 1 atm and a temperature of 13.0 °C. Calculate the volume of carbon dioxide gas that is produced. Round your answer to 3 significant digits. L ロ→ロ AQ X x10 Ś

3.45 mol of LiCl in 3.53 L of solution Express the molarity in moles per liter to three significant figures. 29.23 gC6H12O6 in 1.13 L of solution Express the molarity in moles per liter to three significant figures. 38.0 mgNaCl in 106.2 mL of solution Express the molarity in moles per liter to three significant figures.

Explain the difference between a general mixture and an aqueous mixture.

By pipet, 9.00 mL of a 0.823 M stock solution of potassium permanganate (KMNO4) was transferred to a 50.00-mL volumetric flask and diluted to the calibration mark. Determine the molarity of the resulting solution. HA Value Units

A concentrated perchloric acid solution is 69.8% HCIO4 by mass and its density is 1.68 g mL-1. What volume (in litres) of the concentrated perchloric acid solution is needed to make 2.92L of 3.20 mol L-1 HCIO4(aq)? Molar masses, in g mol-1; HCIO4, 100.458 H2O, 18.016 0.447 L 0.0939 L 0.800 L 0.559 L 0.390 L Back: Question Menu