Try it on paper first. A hint, the key idea and the worked solution are here when you need them.
A stock bottle of nitric acid is by mass, with a density of . Nitric acid is . A student needs of nitric acid. Find the molarity of the stock acid and the volume of it to measure out.
Mass percent . Molarity is moles per litre of solution, and molality is moles per kilogram of solvent. One ppm is of solute in of solution, and one ppb is in . The density joins the mass of a solution to its volume. For dilution, .
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Stock molarity. One litre has a mass of . Of this, is acid: . Moles: . So the stock is .
Step 2. Moles needed. .
Step 3. Volume of stock. We want . Since , .
Answer: the stock is , and of it is made up to with water.
Watch out. Add the acid to the water, never the water to the acid. The mixing gives out a lot of heat.
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