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发帖数: 1320 | 1 【 以下文字转载自 Chemistry 讨论区 】
发信人: ashuang (越忙越年轻), 信区: Chemistry
标 题: Honors Chemistry: Help needed!
发信站: BBS 未名空间站 (Sun Nov 10 21:04:40 2013, 美东)
I can't figure out how to d these problems, I know you are all experts, so
please help me out!
15. A student mixes 85.5 mL of 0.150 M nickel (II) nitrate and 124.4 mL of
0.0888 M sodium hydroxide. (a) Identify the precipitate and give the
molecular, ionic, and net ionic equations. (b) Determine the mass of
precipitate formed, and (c) calculate the concentration of the excess cation
that reacted. (0.512 g, 0.0348 M)
16. When a 0.5250 g sample containing chloride is reacted with silver
nitrate solution 0.5070 g of AgCl is precipitated. (a) What is the %
chloride by mass in the sample? (b) If the sample has a formula of XCl2,
determine the identity of X. (23.88%, 226.0 g/mol, Radium)
17. A student wishes to determine the amount of NaCl and KCl in a 1.484 g
sample that is a mixture of both. She dissolves the sample in distilled
water and then reacts it with excess silver nitrate. If she obtains 3.132 g
of dry silver chloride, what was the amount of KCl and NaCl originally
present in the sample? (0.5267 g NaCl, 0.9574 g KCl)
Could you give me some hints and ideas on how I should approach these
problems quickly? Thanks! |
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