Which of the following solutions is more concentrated? (a) 0.500 M KCl or 0.500 mass % KCl in water

Video transcript

Hey everyone were asked which of the following is more concentrated. 0.300 moller sodium chloride solution versus 0.9%. Mass sodium chloride in water, assume the density of the solutions is the same as water First. Let's go ahead and convert our 0.300 moller sodium chloride solution into mass percent. So essentially our polarity is going to be 0.300 mole of sodium chloride, divided by one leader of solution. Using this information, let's first calculate the mass of sodium chloride. Taking our 0.300 mole of sodium chloride. We're going to use dimensional analysis and we know that we have 58. g of sodium chloride per one mole of sodium chloride. When we calculate this out, we end up with a mass of 17.5 g of sodium chloride. Now let's go ahead and calculate the mass of our solution. Using that one leader we stated earlier, we first want to convert this into milliliters and we know that per one leader we have to the third milliliters. Using the density, which was said to be the same as water. We have one g of solution per one millimeter. So when we calculate this out, We end up with a mass of our solution being 1.00 times 10 to the 3rd g of solution. Now, to calculate our mass percent our percent sodium chloride Is going to be the mass of sodium chloride, which was 17.5 g of sodium chloride. And we're going to divide this by the mass of our solution, which was 1000 g and we want to multiply this by 100. Since we want this in percentages, This will get us to a mass percent of 1.75% mass sodium chloride in water. Now comparing that 1.75% from our 0.300 Moeller vs that 0.9% mass of sodium chloride, and water. We can see that the 0.300 moller solution is more concentrated, Since we're comparing 1.75% from 0.300 Moeller vs that 0.9%. Now, I hope that made sense. And let us know if you have any questions.