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Preparation of primary standard

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ss99:
The question goes like "knowing that commercial HNO3 is not a primary standard substance (density 1.42 g/ml, weigh 70%) whereas pure Na2CO3 is a primary standard
Describe how can you prepare 1L of 0.1M HNO3 using both of substance above"
I started by calculating the mass of HNO3 then I didn't know where to go, need some help:(

chenbeier:
Calculate how much gramm contain 0,1 M HNO3.

This mass has to be obtain from the given nitric acid. Convert to  the 70%
.
Change it to the volume by using the density.

Then design a experiment by using the carbonate to verify the content.
Now give your ideas.

ss99:
Then I can say 0.1mol/L*1L*63g/mol*0.7=4.41g which will be the mass of HNO3 that we will use
Then we can say the volume that we will need will be  4.41g÷(1.42g/ml)= 3.10ml of HNO3

Then the moles from standard HNO3 will be equal to the moles of Na2CO3
So we can obtain the mass of Na2CO3 0.1mol*106g= 10.6g of Na2CO3

chenbeier:
The calculation with  the percentage is wrong. You have to divide by 0.7. The mass obtained with the mole is 100%. So the mass has to be higher if it is only 70%

The sodium carbonate neutralize 2 time of nitric. Why?

AWK:

--- Quote from: ss99 on March 20, 2019, 02:54:03 PM ---Then I can say 0.1mol/L*1L*63g/mol*0.7=4.41g which will be the mass of HNO3 that we will use
Then we can say the volume that we will need will be  4.41g÷(1.42g/ml)= 3.10ml of HNO3

--- End quote ---
For 0.1 M solution, you need 6.3 g of 100 % nitric acid!
Concentrated 70% acid will weigh a little more.

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