A dandruff shampoo contains pyrithion, C10H8N2O2S2, which acts as an antibacterial and antifungal agent. What is the empirical formula of pyrithion?

Problem Session 2

Chapters: 6, 7, 12, 13

 

 

Directions:  Answer each of the following questions in complete sentences where appropriate.  Be sure to show all of your work and report your answers to the correct number of significant figures.

 

Question 1.      Given the correct IUPAC name for the following compounds

 

 

1. PCl₃ _____________________

 

1. SF₆ _____________________

 

1. Na₂SO₄ _____________________

 

1. MnO _____________________

 

1. (NH₄)₂O _____________________

 

1. RbClO₄ _____________________

 

1. Cd(CN)₂ _____________________

 

1. N₂O₅ _____________________

 

1. Ni(HSO₄)₂ _____________________

 

1. HCl _(g) _____________________

 

1. HCl _(aq) _____________________

 

1. FeCl₂·6H₂O_____________________

 

1. Al₂O₃ _____________________

 

1. V₂O₅ _____________________

 

1. H₃PO_{3 (aq)} _____________________

 

1. IF₅ _____________________

 

Question 2.      Write the correct formula for the following compounds:

 

 

1. Vanadium(III) chlorate _________

 

1. Aresenic acid _________

 

1. Carbon tetrachloride _________

 

1. Hydrocyanic acid _________

 

1. Iodine trichloride _________

 

1. Dichlorine heptoxide _________

 

1. Sodium hydrogen sulfate _________

 

1. Mercury(II) phosphate _________

 

1. Stannous fluoride _________

 

1. Bismuth(III) cyanide _________

 

1. Tungsten(II) nitride _________

 

1. Boron trichloride _________

 

1. Hydrogen sulfide _________

 

1. Disulfur dichloride _________

 

1. Nickel(II) fluoride _________

tetrahydrate

1. Xenon tetrafluoride _________

 

 

 

Question 3.      A dandruff shampoo contains pyrithion, C₁₀H₈N₂O₂S₂, which acts as an antibacterial and antifungal agent.

1. What is the empirical formula of pyrithion?

 

 

 

1. What is the molar mass of pyrithion?

 

 

 

 

 

1. What is the percent composition of pyrithion?

 

25. How many atoms of C are in 25.0 g pyrithion?

 

8. How many moles of pyrithion contain 8.2 x 10²⁴ atoms of nitrogen?

 

 

 

 

4. How many grams of S are in 4.56 moles of pyrithion?

 

Question 4.      A sample contains 70.6% Hg, 12.5% Cl, and 16.9% O.  If it has a molar mass of about 568 g/mol, what are the empirical and molecular formulas?

Question 5.      A 14.1 mg sample of a hydrocarbon was burned in air.  The products were 38.8 mg of CO₂ and 31.7 mg of water.  What is the empirical formula of the hydrocarbon?

 

 

 

 

 

 

Question 6.      A 0.2417 gram sample of a compound known to be composed of C, H, O and Cl only, is burned in oxygen yielding 0.4964 grams of carbon dioxide and 0.0846 grams of water.  A separate 0.1696 gram sample of the compound is fused with sodium metal, the products dissolved in water and the chloride quantitatively precipitated with silver nitrate to yield 0.1891 grams of AgCl.  What is the simplest empirical formula for the compound (Challenge Problem)?

Question 7.      Write the shorthand electronic configuration for the following:

 

1. Si: ________________________________________________

 

1. Pb: ________________________________________________

 

1. Cl: ________________________________________________

 

1. Cr²⁺: ________________________________________________

 

1. S^2-: ________________________________________________

 

1. Pb⁴⁺: ________________________________________________

 

 

Question 9.      Identify each bond as ionic, polar covalent, or nonpolar covalent, use Figure 12.9, page 347 of the textbook.  Show the distribution of charge.

 

1. Sb-H       _____________________

 

1. B-H       _____________________

 

1. P-F       _____________________

 

1. Rb-Br       _____________________

 

 

 

 

Question 10.    Compare the electron dot formulas of BF₃ and NF₃.  Why do these molecules have different shapes?

Question 12.    If a nonmetal has 5 valance electrons, how many bonds it is most likely to form?  How many lone pairs will it most likely have?

 

 

Question 13. Complete the following mole dimensional analysis.

 

1. How many moles in 28 grams of CO2 ?

 

1. What is the mass of 5 moles of Fe2O3 ?

 

1. Find the number of moles of argon in 452 g of argon.

 

1. Find the grams in 1.26 x 10-4mol of HC2H3O

 

2. Find the mass in 2.6 mol of lithium bromide

 

2. Find the mass in grams of 2.00 x 1023 molecules of F2.

 

1. Find the mass, in grams, of 1.00 x 1023 molecules of N

 

3. How many moles of magnesium is 3.01 x 1022 atoms of magnesium?

 

 

4. How many molecules are there in 4.00 moles of glucose, C6H12O6?

 

1. How many moles are 1.20 x 1025 atoms of phosphorous?

 

1. How many atoms are in 0.750 moles of zinc?

 

1. How many molecules are in 0.400 moles of N2O5?

Question 14.    For each molecule: a) draw the Lewis structure; b) give the electron pair geometry; c) give the molecular shape; d) give the bond angle; e) identify the molecule as polar or nonpolar.

 

	Dichloromethane, CH2Cl2	Gallium trihydride, GaH3
	Chlorate ion	Cyanate ion, OCN– (resonance)
	ClNO2 (resonance)	Nitrogen dioxide ion, NO2+

 

Question 15.    Draw Lewis structures for the following organic molecules and identify the electronic and molecular geometry around each “central” atom.

 

	C:   CH3CH2CH2CH3	C:   N:   H2NCONH2
	Butane	Urea
	C:   O:   CH3OH	C:   C:   O:   CH3COOH
	Methanol	Ethanoic acid
	C:   C2H4	C:   C2H4Cl2
	Ethene	Dichloroethane (2 different structures)