1. Chemical Measurements
Metric Prefixes serve as labels for common base units.
Metric Prefix Multipliers
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in this video, let's explore metric prefixes we're gonna say here. Generally we use scientific notation anytime we're trying to change a very large number or very small number into something that's more manageable. But when it comes to analytical chemistry we need to go a step further and traditionally we'll use metric prefixes in order for us to convert very large and very small numbers into something that's easier for us to understand. Now, metric prefixes serve as just a label for common base units. For example. Um one kilometer is equal to 10 to the three m or one micro leader equals 10 to the negative. Six leaders realize here that our metric prefixes are the labels that go in front of some common types of base units. So base unit of meters here and the base units of leaders here We're accustomed to seen when it comes to metric prefixes as being between 10 to the negative 12 To 10 to the 12. This is what we've customarily seen before. But remember analytical chemistry is a chemistry of precision. And because of that we're gonna have to expand the way we look at metric prefixes and look at additional ones that we may not have known beforehand. So this includes expanding all the way to 10 to the negative 24 And all the way up to 10 to the 24. So here we have our basic multiplier for our metric prefixes on top 10 to the negative 24 to 10 to the 24 below. We have the name of that particular metric prefix from yoke toe all the way to Yoda And then the different symbols that are associated with them. Now remember here 10 of the zero serves as just our base In terms of this graph and we're going to say here that remember anytime we do any types of metric prefix conversions we're gonna say that one is associated with our metric prefix. That's why I said that one kg, 1 kg meter is 10 to the three so one kg is 10 to the three. That's why I said that. One micro So micro one micro which is right here is 10 to the negative six up here as we delve deeper and deeper into analytical chemistry. Realize that metric prefixes will always be in play in some way or another. So it's important to commit to memory this chart that we have here in terms of our metric prefix conversions from this will move on to example one. What we put into action some of the key principles we've just learned. So come back, take a look at the next video and see how we approach calculating different types of metric prefixes when it comes to any type of word prob
Whenever using the metric prefix chart, remember that “1” is associated with the metric prefix.
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So in terms of this example here it says it is safe to assume that all dilute aqueous solutions have a density near one g per one millimeter. It says if a solution is 2.50 parts per 1000 express the concentration in the following units. So here we need to convert 2.50 parts per 1000 into PICO grams over Death. Leaders now realize here that if we're taking a look at our metric prefix chart that when we're talking about parts per 1000 parts per billion and parts per million, they're involved in this metric prefix chart. In some way we're gonna say here that one, parts per 1000 is equivalent to one g over one leader, one assuming density is around one. We're gonna say here that one parts per million Is equal to one mg per one leader. So these are important things to remember. And then finally we can say here that one parts per billion is equal to one microgram per one leader. And if we're looking at all these expressions, we can see that we have grams involved, milligrams involved and micrograms involved. So we can say here by looking at this metric prefix conversions chart, We can come into memory that 10 to the six, which deals with micro can be linked up with parts per billion. 10 to the -3 which is Mili Milligrams is connected to parts per million And then 10 to the zero which is our base can be connected to parts per 1000. So use that as a way of remembering on what each one of these parts per whatever relates to in terms of mass over volume. So we have 2.5 zero pp. T. here. So that translates into we said 2.50 g per one liter. Because PPT is one g per one. Um Leader. So we know that we have 2.50 g per one liter. So all we have to do is convert grams into PICO grams and then convert leaders into death leaders and will be done. So let's first convert grams into PICO grams. We want to get rid of grams though grams go on the bottom. We want PICO grams so they go on top. Remember one is associated with metric prefix. My metric prefix series PICO. So one PICO is 10 to the negative 12 g grams cancel out. So now I have PICO grams over leaders. Next I need to convert leaders into desk leaders. So leaders are here on the bottom so to get rid of them I'll put leaders here on the top. We can go directly from leaders to desk leaders. So desk leaders go here on the bottom. Remember one is associated with my metric prefix. So one dc Is 10 to the -1. So all we have to do now is do 2.50 times 10 to the negative one divided by 10 to the negative 12. Since these are tens to powers it probably best to put them in parentheses within your calculator. Otherwise you may get the incorrect answer. So when we multiply everything on the top, divide by the bottom, we get 2.5 Times 10 to the 11 PICO grams per deciliter so that their represents our final answer. Now that you've seen the applications of parts per 1000. Try to do the practice problem that's left on the bottom. Work it out, convert parts per billion into the desired units that are asked and then if you get stuck or just want to see how I approach it, just come back and take a look at the next video.
Based on the above example convert 5.71 ppb into the units presented below.