1. Classify each of the following as a pure substance or a mixture; if a mixture, indicate whether it is homogeneous or heterogeneous: (a) concrete; (b) seawater; (c) magnesium; (d) gasoline.

2. Suggest a way to determine whether a colorless liquid is pure water or a solution of salt in the water, without tasting the liquid.

3. A solid white substance A is heated strongly in the absence of air. It decomposes to form a new white substance B and a gas C. The gas has exactly the same properties as the product obtained when carbon is burned in an excess of oxygen. What can we say about whether solids A and B and the gas C are elements or compounds?

4. Label each of the following as either a physical process or a chemical process: (a) corrosion of aluminum metal; (b) melting of ice; (c) pulverizing an aspirin; (d) digesting a candy bar; (e) explosion of nitroglycerin.

5. Perform the following conversions: (a) 454 mg to g; (b) 5.0 X 10^-9 m to pm; (c) 3.5 X 10^-2 mm to µm.

6. (a) A sample of carbon tetrachloride, a liquid once used in dry cleaning, has a mass of 39.75 g and a volume of 25.0 mL. What is its density? (b) The density of platinum is 23.4 g/cm³. Calculate the mass of 75.0 cm³ of platinum. (c) The density of magnesium is 1.74 g/cm³. What is the volume of 275 g of this metal?

7. (a) To identify a liquid substance, a student determined its density. Using a graduated cylinder, she measured out a 45-mL sample of the substance. She then measured the mass of the sample, finding that it weighed 38.5 g. She knew that the substance had to be either isopropyl alcohol (density 0.785 g/mL) or toluene (density 0.866 g/mL). What is the calculated density and the probable identity of the substance? (b) An experiment requires 45.0 g of ethylene glycol, a liquid whose density is 1.114 g/mL. Rather than weigh the sample on a balance, a chemist chooses to dispense the liquid using a graduated cylinder. What volume of the liquid should he use? (c) A cubic piece of metal measures 5.00 cm on each edge. If the metal is nickel, whose density is 8.90 g/cm³, what is the mass of the cube?

8. Make the following conversions: (a) 62¡F to ¡C; (b) 216.7¡C to ¡F; (c) 223¡C to K; (d) 315 K to ¡F; (e) 2500¡F to K.

9. Indicate which of the following are exact numbers: (a) the mass of a paper clip; (b) the surface area of a dime; (c) the number of inches in a mile; (d) the number of ounces in a pound; (e) the number of microseconds in a week; (f) the number of pages in this book.

10. What is the number of significant figures in each of the following measured quantities? (a) 1282 kg; (b) 0.00296 s; (c) 8.070 mm; (d) 0.0105 L; (e) 9.7750 X 10^-4 cm.

11. Carry out the following operations and express the answers with the appropriate number of significant figures: (a) 1.24056 + 75.80; (b) 23.67 75; (c) 890.00 X 112.3; (d) 78,132/2.50.

12. Perform the following conversions: (a) 0.076 L to mL; (b) 5.0 X 10^-8 m to nm; (c) 6.88 X 10⁵ ns to s; (d) 1.55 kg/m³ to g/L.

13. Perform the following conversions: (a) 8.60 mi to m; (b) 3.00 days to s; (c) $1.55/ gal to dollars per liter; (d) 5.0 pm/ms to m/s; (e) 75.00 mi/hr to m/s; (f) 55.35 ft³ to cm³.

14. The density of air at ordinary atmospheric pressure and 25¡C is 1.19 g/L. What is the mass, in kilograms, of the air in a room that measures 12.5 X 15.5 X 8.0 ft?

15. A copper refinery produces a copper ingot weighing 150 lb. If the copper is drawn into wire whose diameter is 8.25 mm. How many feet of copper can be obtained from the ingot? The density of copper is 8.94 g/cm³.

16. A sample of ascorbic acid (vitamin C) is synthesized in the laboratory. It contains 1.50 g of carbon and 2.00 g of oxygen. Another sample of ascorbic acid isolated from citrus fruit contains 6.35 g carbon. How many grams of oxygen does it contain? Which law are you assuming in answering this question?

17. The annual production of sodium hydroxide in the United States in 1994 was 25.83 billion pounds. (a) How many grams of sodium hydroxide were produced in that year? (b) The density of sodium hydroxide is 2.130 g/cm³. How many cubic kilometers were produced?

18. A 15.0-cm long cylindrical glass tube, sealed at one end is filled with ethanol. The mass of ethanol needed to fill the tube is found to be 9.64 g. The density of ethanol is 0.789 g/mL. Calculate the inner diameter of the tube in centimeters.

19. How many protons, neutrons, and electrons are in the following atoms: (a) ⁴⁰Ar; (b) ⁵⁵Mn; (c) ⁶⁵Zn; (d) ⁷⁹Se; (e) ¹⁸⁴W; (f) ²³⁵U?

20. Fill in the gaps in the following table, assuming each column represents a neutral atom:

21. Write the correct symbol, with both superscript and subscript, for each of the following (use the list of elements on the front inside cover): (a) the isotope of sodium with mass 23; (b) the nuclide of vanadium that contains 28 neutrons; (c) an particle; (d) the isotope of chlorine with mass 37; (e) the nuclide of magnesium that has a equal number of protons and neutrons.

22. For each of the following elements, write its chemical symbol, locate it in the periodic table, and indicate whether it is a metal, metalloid, or nonmetal: (a) silver; (b) helium; (c) a phosphorus; (d) cadmium; (e) calcium; (f) bromine; (g) arsenic.

23. For each of the following elements, write its chemical symbol, determine the name of the group to which it belongs (Table 2.3), and indicate whether it is a metal, metalloid, or nonmetal: (a) potassium; (b) iodine; (c) magnesium; (d) argon; (e) sulfur.

24. From the following list, find the groups of compounds that have the same empirical formula: C₂H_2, N₂O₄, C₄H₄, C₆H₆, NO₂, C₃H₆, C₄H₈.

25. Each of the following elements is capable of forming an ion in chemical reactions. By referring to the periodic table, predict the charge of the most stable ion of each: (a) Al; (b) Ca; (c) S; (d) I; (e) Cs.

26. Using the periodic table to guide you, predict the formula and the name of the compound formed by the following elements: (a) Ga and F; (b) Li and H; (c) Al and I; (d) K and S.

27. Predict the empirical formula for the ionic compound formed by (a) Ca²⁺ and Br^-; (b) NH₄⁺ and Cl^-; (c) Al³⁺ and C₂H₃O₂^-; (d) K⁺ and SO₄^2-; (e) Mg²⁺ and PO₄^3-.

28. Predict whether each of the following compounds is molecular or ionic: (a) B₂H₆; (b) CH₃OH; (c) LiNO₃; (d) Sc₂O₃; (e) CsBr; (f) NOCl; (g) NF₃; (h) Ag₂SO₄.

29. Provide names for the following ionic compounds: (a) AlF₃; (b) Fe(OH)₂; (c) Cu(NO₃)₂; (d) Ba(ClO₄)₂; (e) Li₃PO₄; (f) Hg₂S; (g) Ca(C₂H₃O₂)₂; (h) Cr₂(CO₃)₃; (i) K₂CrO₄; (j) (NH₄)₂SO₄.

30. Write the chemical formulas for the following compounds: (a) copper (I) oxide; (b) potassium peroxide; (c) aluminum hydroxide; (d) zinc nitrate; (e) mercury (I) bromide; (f) iron (III) carbonate; (g) sodium hypobromite.

31. Give the name or chemical formula, as appropriate, for each of the following molecular substances: (a) SF₆; (b) IF₅; (c) XeO₃; (d) dinitrogen tetroxide; (e) hydrogen cyanide; (f) tetraphosphorus hexasulfide.

32. Write the chemical formula for each substance mention in the following word descriptions (use the front inside cover to find the symbols for the elements you dont know). (a) Zinc carbonate can be heated to form zinc oxide and carbon dioxide. (b) On treatment with hydrofluoric acid, silicon dioxide forms silicon tetrafluoride and water. (c) Sulfur dioxide reacts with water to form sulfurous acid. (d) The substance hydrogen phosphide, common called phosphine, is a toxic gas. (e) Perchloric acid reacts with cadmium to form cadmium(II) perchlorate. (f) Vanadium(III) bromide is a colored solid.

33. From the following list of elements Ar, H, Ga, Al, Ca, Br,Ge, K, O pick one that best fit each description; use each element only once: (a) an alkali metal; (b) an alkaline earth metal; (c) a noble gas; (d) a halogen; (e) a metalloid; (f) a nonmetal listed in group IA; (g) a metal that forms a 3+ ion; (h) a nonmetal that forms a 2- ion; (i) an element that resembles aluminum.

34. Fill in the gaps in the following table

35. Many familiar substances have common, unsystematic names. For each of the following, give the correct systematic name: (a) saltpeter; KNO₃; (b) soda ash, Na₂CO₃; (c) lime, CaO; (d) muriatic acid, HCl; (e) Epsom salts, MgSO₄; (f) milk of magneisa, Mg(OH)₂.