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### question on fundamentals G

Posted: Mon Apr 09, 2018 8:39 pm
A student prepared a solution of sodium carbonate by adding 2.111 g of the solid to a 250.0-mL volumetric flask and adding water to the mark. Some of this solution was transferred to a buret. What volume of solution should the student transfer into a fl ask to obtain (a) 2.15 mmol Na; (b) 4.98 mmol CO32; (c) 50.0 mg Na2CO3?

### Re: question on fundamentals G

Posted: Mon Apr 09, 2018 9:29 pm
Hello, with help this is what we came up with:
Find the molarity of Na2CO3=0.08 M
convert mmol of Na+ to moles and convert mmol of CO3^2- and convert mmol of Na2CO3 to moles
mol of Na+/2(0.08M)
mol of CO3^2-/(0.8M)
mol of Na2C03/(0.8M)

### Re: question on fundamentals G

Posted: Wed Apr 11, 2018 9:02 pm
First, you need to find the molarity of Na2CO3

M=n/V= (2.11gNaCO3mol/105.951g)/.25L = .08 molL-1

Then you can solve each equation for a volume

a) V= 2.15x10-3 mol Na+ x 1 mol Na2C03 / .08 molNa2CO3 L-1 x 2mol Na+ = 1.35x 10-2L

b) V= 4.98x10-3 mol CO3 x 1 mol Na2C03 / .08 molNa2CO3 L-1 x 2mol CO3 = 6.3 x10-2L

c) V= .5g Na2CO3/ 105.951gmol-1NaCO3 x .08 molL-1 = 5.9 x10-3L

### Re: question on fundamentals G

Posted: Sun May 06, 2018 3:09 pm