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G.23 from HW

Posted: Sun Apr 08, 2018 4:05 pm
by MeghetyManoyan1A
For problem G.23,

"In medicine it is sometimes necessary to prepare solutions with a specific concentration of a given ion. A lab technician has made up a 100.0-mL solution containing 0.50 g of NaCl and 0.30 g of KCl, as well as glucose and other sugars. What is the concentration of chloride ions in the solution?,"

I am confused on how to find the concentration of only the chloride ions. Do we find separate concentrations for NaCl and KCl?

Re: G.23 from HW  [ENDORSED]

Posted: Sun Apr 08, 2018 5:08 pm
by Kalsuda Lapborisuth 1B
Because when KCl and NaCl dissolves in water, they become K+and Cl- and Na+ and Cl- respectively, you can approach this problem by simply adding the moles of KCl and NaCl together to find the total molar concentration of Cl- in 100.0mL solution.

Re: G.23 from HW

Posted: Sun Apr 08, 2018 6:14 pm
by AshleyLamba1H
The units for molar concentration is mol/L. Therefore, you must first convert the amount of grams of Cl- to moles, and then divide that by .100 L (100 mL).

Re: G.23 from HW

Posted: Sun Apr 08, 2018 11:01 pm
by jadam_1E
For this problem, I approached it by thinking that for NaCl, the proportion of Cl ions to NaCl formula units is 1:1, and the proportion of Cl atoms to KCl formula units is also 1:1. Therefore, the concentration of Cl ions in the solution will be the same as the concentration calculated by converting .50g NaCl and .30g KCl to moles, adding together these separate number of moles, and dividing by the given volume of the solution which is 100mL.

Re: G.23 from HW

Posted: Sun Apr 15, 2018 2:02 pm
by Ani Boyadjian 1A
I first converted both NaCl and KCl to moles, then added them together and finally multiplied by (1/0.1L)