Essay Homework

748 Words Dec 26th, 2011 3 Pages
Assigment 1: Foundations: Atoms, Molecules, and Ions
1.1 A 47.3-mL sample of ethyl alcohol (ethanol) has a mass of 37.32 g. What is its density? 1.2 If 116 g of ethanol is needed for a chemical reaction, what volume of liquid would you use? The density of ethanol is 0.789 g/mL

1.3 Battery acid is 40.0% sulfuric acid, H2SO4, and 60.0% water by mass. Its density is
1.31. Calculate the mass of pure H2SO4 in 100.0 mL of battery acid.

1.4 How many moles of atoms does 136.9 g of iron metal contain? 1.5 A stack of 500 sheets of typing paper is 1.9 inches thick. Calculate the thickness, in inches and in miles, of a stack of typing paper that contains one mole (Avogadro’s number) of sheets (1 inch = 2.54 cm)

1.6 Compounds containing
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1.12 What is the maximum mass of Ni(OH)2 that could be prepared by mixing two solutions that contain 25.9 g of NiCl2 and 10.0 g of NaOH, respectively? NiCl2 + NaOH -- > Ni(OH)2 + NaCl

1.13 A 15.6-gram sample of C6H6 is mixed with excess HNO3. We isolate 18.0 grams of
C6H5NO2. What is the percent yield of C6H5NO2 in this reaction?

1.14 Phosphoric acid, H3PO4, is a very important compound used to make fertilizers. It is also pres- ent in cola drinks. H3PO4 can be prepared in a two-step process. Rxn 1: P4 +O2 --- > P4O10 Rxn 2: P4 O10 +H2O --- > H3PO4 We allow 272 grams of phosphorus to react with excess oxygen, which forms tetraphosphorus decoxide, P4O10, in 89.5% yield. In the second step reaction, a 96.8% yield of H3PO4 is obtained. What mass of H3PO4 is obtained?

1.15 2.00 grams of ammonium sulfate was dissolved in distilled water and made up to 250 mL in a volumetric flask. A 25.0 mL portion of this solution was boiled with 50.0 mL of 0.100 M sodium hydroxide solution until no more ammonia gas was evolved. Then excess sodium hydroxide in the resulting solution required for neutralization, 24.30 mL of HCl 0.100M. Calculate the percentage purity of the sample.

1.16 Write the correct formulae/ions for:
Potassium sulfite:………………. Dinitrogen pentoxide:……………. Nitrorous acid: ………………… Sodium hyperchlorite…………… Chloric acid………………… Hydride ion:………………… Coprous ions: ……………… Mercuric

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