Here. It states that Massachusetts limits the amount of lead in drinking water to 219 parts per billion. Part a states express the total in polarity and part B states, what will happen to the polarity of the solution as the temperature increases? Will it increase decrease or remain constant? All right. So let's first tackle part a And remember here they're giving us parts per billion. Remember parts per billion. One Parts per billion means one microgram over one liter. So, by telling us that we have 219 parts per billion of lead. It's really saying that we have 219 micrograms of lead for every one leader, we need more clarity and more clarity is just simply moles over leaders. So all we have to do here is change Michael grams, two g and then from grams to moles. So we want to get rid of micrograms. So micrograms go on the bottom one. Microgram is 10 to the negative six g. So micrograms are gone. Then we're going to say here for every one mole of lead. We have 207.2 g as the massive lead according to the periodic table. So at the end here we'll have moles over leaders which will be our polarity. So that comes out to being approximately 1.6 times 10 to the negative six Mohler of lead for part B. Now here we're asked what's gonna happen to the polarity as the temperature increases? Remember polarity equals moles of our saw you divided by leaders of solution now as you increase the temperature that's going to cause an increase in your volume. So what's happening here is the leaders on the bottom it's going to expand. It's gonna get become a larger value while the moles stay constant. So your top portion is staying the same as your bottom is increasing. So that means overall your polarity will decrease. So we'd expect similarity to to decrease as the temperature increases, the same thing is happening here with density. Remember we said as the temperature was increasing, we can see that our density is dropping. That's because density equals mass over volume. Again, by increasing the temperature, you're increasing your volume as your top portion stays constant. So as a result of this, your density drops. So just remember some of the fundamentals when it comes to thermal expansion. Remember we're trying to minimize all outside factors to make sure our data is not corrupted. So we have to take into account that concentration and density of a solution is determined and affected by changes in temperature. Now that we've seen this process will move on to other examples dealing with thermal dependency
