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Chemistry - Regents Exams and Answers

Condition of Item(s):	Acceptable	Author(s):	Stanleu H. Kaplan
Type:	Paperback	Publisher:	Barron’s Educational Series
Catagory:	Educational Book	Functionality:	Excellent
Last Copywrite:	1959	ISBN/Congress/ID:	N/A
Weight:	8 oz	Lot:	Private - B5

Notes: Browning and a tiny bit basement smell

36. water Anhydrous copper sulfate is a white powder. When water is present, a blue solution of copper sulfate is formed because of the formation of the blue hydrated cupric ion.

37. ions Water solutions of acids, bases, or salts contain charged particles called ions. In the case of electrovalent compounds such as salts and strong bases, the ions exist even in the solid .state, arranged in a crystal lattice. When dissolved in water, the dipole water molecules exert an attractive force on these ions causing them to dissociate so that they are free to move. Acids and some bases are covalent compounds that are polar in nature ( dipoles ) because of the unbalanced (asymmetrical) electrical charges. The action of the dipole water molecules breaks the covalent bond resulting in the formation of ions.

38. +2 When a mercury salt reacts with sodium chloride, a chloride compound of mercury is formed. From the table of solubilities in water we see that mercurous chloride (mercury I) is insoluble, forming a precipitate, and that mercuric chloride ( mercury II ) is soluble, forming no precipitate. Since no precipitate was formed, the mercury had a valence of +2.

39. emulsion Colloidal particles are intermediate in size between those in solution and those in suspension. If a mixture of two immiscible liquids (such as oil and water) is vigorously shaken, the particles of oil will be broken down to colloidal size. We then say that we have a colloidal suspension of oil in water. Such a colloidal suspension of one liquid in another is termed an emulsion. Most emulsions are not very stable, and the dispersed phase (such as the oil) soon separates out. An emulsion's stability can be increased by the addition of an emulsifying agent such as soap.

10. carbon dioxide A bicarbonate contains the HCOs" ion. When an acid such as the acetic acid in vinegar is added, the hydrogen ion of the acid combines with the bicarbonate ion to form carbonic acid. The carbonic acid is unstable and decomposes to form carbon dioxide- and water.

H+ + HCO₃- -» H₂CO₃ -> H₂O + CO₂ f

41. decreases ' Gases, unlike most solids, are less soluble at higher temperatures. Thus bubbles of air will appear as a beaker of cold tap water is heated. For the same reason the sparkle of carbonated beverages can be maintained longer if the beverages are kept at lower temperatures since the carbon dioxide is then more soluble.

42. remains the same Rare .gases are inert elements. The atoms are stable since the outer valence shells have complete orbits of eight electrons (two for helium). They show no chemical activity, for there is no tendency for these inert elements to form compounds by losing, gaining or sharing electrons.

43. decreases A catalyst is a substance that speeds .up- or retards the velocity of a chemical reaction without any permanent change in the catalyst itself. An example of a positive catalyst is manganese dioxide which speeds up the decomposition of potassium chlorate to produce