26.07.2021 Views

General Chemistry Principles, Patterns, and Applications, 2011

General Chemistry Principles, Patterns, and Applications, 2011

General Chemistry Principles, Patterns, and Applications, 2011

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

7. In a qualitative analysis laboratory, a student initially treated his sample of metal ions with 6 M HNO 3 instead<br />

of 6 M HCl, recognizing his mistake only after the acid-insoluble sulfides had been precipitated. He decided to<br />

simply add 6 M HCl to the filtrate from which the sulfides had been removed, but he obtained no precipitate.<br />

The student therefore concluded that there were no Ag + , Hg 2 2+ , or Pb 2+ cations in his original sample. Is this<br />

conclusion valid?<br />

8. Using qualitative analysis, a student decided to treat her sample with (NH 4 ) 2 S solution directly, skipping the<br />

HCl <strong>and</strong> acidic H 2 S treatments because she was running out of time. In a sample that contained Ag + , Hg 2 2+ ,<br />

Cd 2+ , Sb 3+ , <strong>and</strong> Zn 2+ , which metal ions was she most likely to obtain in the resulting precipitate?<br />

A N S W E R S<br />

1.<br />

a. 4.3 g<br />

b. 5 × 10 −6 M<br />

2.<br />

3.<br />

a. 4.4 × 10 −7 M<br />

b. 0.84 M<br />

4.<br />

5.<br />

6.<br />

Saylor URL: http://www.saylor.org/books<br />

Saylor.org<br />

1613

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!