October 15, 2019, 08:00:46 PM
Forum Rules: Read This Before Posting

### Topic: Impossible question I am trying to solve right now. Will cash app $3 if correct (Read 427 times) 0 Members and 1 Guest are viewing this topic. #### choi253 • Very New Member • Posts: 1 • Mole Snacks: +0/-0 ##### Impossible question I am trying to solve right now. Will cash app$3 if correct
« on: June 25, 2019, 03:00:34 AM »
I've been trying to solve this problem and every answer that I found on the internet is wrong. Could one of you please help me out by solving this. Thank you so much.

A solution is prepared by mixing 50.0 mL of 0.50 M Cu(NO3)2 with 50.0 mL of 0.50 M Co(NO3)2. Sodium hydroxide is added to the mixture. Which hydroxide precipitates first and what concentration of hydroxide ions present in solution will accomplish the separation?Ksp = 2.2 × 10–20 for Cu(OH)2, Ksp = 1.3 × 10–15 for Co(OH)2
« Last Edit: June 25, 2019, 03:20:36 AM by choi253 »

#### mjc123

• Chemist
• Sr. Member
• Posts: 1626
• Mole Snacks: +230/-11
##### Re: Impossible question I am trying to solve right now. Will cash app $3 if correct « Reply #1 on: June 25, 2019, 04:49:56 AM » Please note it is a forum rule that you must show some effort before receiving help. Nobody is going to solve this for you. "Every answer" you found is wrong? Presumably some say copper, some say cobalt, they can't both be wrong. How do you know they are wrong? By your own work, or comparing it with a given "right" answer? Do you know what "Ksp" means, and how to use it? #### Babcock_Hall • Chemist • Sr. Member • Posts: 3842 • Mole Snacks: +243/-16 ##### Re: Impossible question I am trying to solve right now. Will cash app$3 if correct
« Reply #2 on: June 25, 2019, 11:05:53 AM »
An easy way to get a start on this problem would be to calculate the new concentrations of cobalt nitrate and copper nitrate.

#### AWK

• Retired Staff
• Sr. Member
• Posts: 6645
• Mole Snacks: +479/-80
• Gender:
##### Re: Impossible question I am trying to solve right now. Will cash app \$3 if correct
« Reply #3 on: June 25, 2019, 12:37:31 PM »
I've been trying to solve this problem and every answer that I found on the internet is wrong.
I advise you to learn to search better. On the internet, you can find a bad and good solution to this problem. Good solution use a slightly different value for Ksp of Co(OH)2 - 1.6 × 10–15.

The first part of the task can be solved without any counting. All you have to do is read the relevant chapter in the textbook carefully. Then also calculating the second part will not be a problem.
AWK