What mass of HClO4 must be present in 0.500 L of solution to obtain a solution with each pH value? b. pH = 1.50

Video transcript

Hey everyone, we're asked to calculate the mass of nitric acid needed to prepare a 0.75 liter of solution with a ph of 1.28. 1st, let's go ahead and write out our balanced chemical reaction. Now we have nitric acid and we know that this is one of our strong acids. So it's going to completely disassociate into our hydrogen ions plus our nitrate ions. Now let's go ahead and calculate the concentration of our hydrogen ions and we can do so by taking 10 to the negative ph and in this case it will be 10 to the negative 1.28, which will get us to a value of 0.5248 moller. Now to calculate the mass of our nitric acid, we can go ahead and start off with our 0.75 L of solution. And using the concentration of our hydrogen ion in our dimensional analysis, we're going to multiply this value by 0. mol of our hydrogen ions. Over leaders. Next looking at our multiple ratios, we know that we have one mole of our hydrogen ion per one mole of our nitric acid. And lastly looking at nitric acids molar mass, we know that we have 63.1 g of nitric acid per one mole of nitric acid. So when we calculate this out and cancel out all of our units, we end up with a value of 2.5 g of nitric acid, which is going to be our final answer. Now, I hope that made sense and let us know if you have any questions.