The sterile saline solution used to rinse contact lenses can be m...

Question

The sterile saline solution used to rinse contact lenses can be made by dissolving 400 mg of NaCl in sterile water and diluting to 100 mL. What is the molarity of the solution?

Accepted Answer

Hey everyone Today, we're being asked to calculate the polarity of a solution prepared by dissolving 80 g of sodium acetate in a C. H. three c. 00. Or N A O A C. For short In enough water to prepare a 1.75 L solution. Now the question is asking us to calculate polarity polarity which is just the moles of solute, which in this case is sodium acetate, N A O A C. Divided by the total leaders of solution. Leaders of solution. Now the problem already gives us our volume. In this case It's 1.75 L. That'll be 1.75 L. So all we need to do is calculate the moles of sodium a city that we have. And the question also gives us the mass of sodium acetate present in the solution. So to convert this mass present into the number of moles it is we can use the molar mass as a conversion factor. And to find the molar mass, you can use the periodic table. sodium has a multi pass of 23g per mole Carbon has a molar mass of 12 g from all. And we have two of those. So we multiply that by two. Same goes for oxygen except for 16 g of per mole. Is that it's a smaller mass. I want to buy buy two. Finally hydrogen has a molar mass of one g per mole and we have three of those. So we multiply by three. So totally. That brings us to 23 plus 24 plus 32 plus three Will bring us to 82 graham Permal of sodium acetate, N A O A. See. So with that in mind we can go ahead and take the mass present in the problem 80 g of sodium acetate and multiply it by the inverse of the molar mass. This puts the mole term on top and allows us to calculate or cancel out the grams term which will leave us exactly with the moles. Don't cancel those two out. And we'll have a value of 0.98 malls of sodium acetate. So now that we have that we can go ahead and plug it back into our polarity formula Polarity is equal to the malls of side Which is 0.98 moles of sodium acetate A. C. Okay divided by The total leaders of solution, the total volume which is 1.75 meters. And this gives us a value Of 0.56 Mohler. So the polarity of the total solution Prepared using 80 g of sodium acetate And want to make a 1.75 L solution. 0.56 Molar. I hope this helps. And I look forward to seeing you all in the next one

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