Victory for the ACT Student Text 15e

338 • S CIENCE

4. Which statement is most correct concerning the separation of Cu 2 from Zn 2 in the same solution? F. Completely different test reagents are used in each of the two steps. G. The same test reagents are used under the same conditions in each of the two steps. H. The same test reagents are used, but –Š‡ ϐ‹”•– •–‡’ —•– „‡ ‹ ƒ ƒŽƒŽ‹‡ environment while the second step must be in an acidic environment. J. The same test reagents are used, but –Š‡ ϐ‹”•– •–‡’ —•– „‡ ‹ ƒ ƒ…‹†‹… environment while the second step must be in an alkaline environment.

5. A clear solution is found, by a method not discussed here, to contain chloride ions ( Cl ). Based on the information provided, what ion could not be present in the solution? A. Carbonate ( CO 2 ) B. Cupric ( Cu 2 ) C. Silver ( Ag ) D. Zinc ( Zn 2 )

Throwback to Science Remember, when positive and negative ions are placed in the same solution, they will become an ionic compound if the attraction between the two oppositely charged ions is greater than the attraction of the ions to the water molecule. This is what is occurring in the experimental chart in Passage I. To predict which negative and positive ions will form a compound, keep the following rule in mind: An ionic compound is always neutral, meaning that the charges of the ions must balance out. This means an ion with a positive charge of two can bond with another ion that has a negative charge of two or two ions with negative charges of one each.

Passage II Š‡…Šƒ”– „‡Ž‘™ •Š‘™• –Š‡ ϐŽƒ˜‘” ’”‡ˆ‡”‡…‡• ‘ˆ ‹…‡ ™Š‡ ‘ˆˆ‡”‡† ˜ƒ”‹‘—• ϐŽ—‹†• –‘ †”‹ ƒ– different ages.

6. Which category on the chart shows no preference between water and the tested ϐŽƒ˜‘”ǫ F. Three months of age/sugar G. Six months of age/salt H. Three months of age/salt J. Nine months of age/sugar

7. Which statement about mice is supported by the information in the chart? A. As age increases, the preference for all tested sugars increases. B. As age increases, the preference for all tested salts increases. C. As age increases, differences between sugars cannot be detected, and differences between salts cannot be detected. D. As age increases, differences between sugars can be detected, and differences between salts can be detected.