So In this example question, it says Osmium, one of the densest elements on earth, has an actual mass of 190.23g according to the table above, What is its value in terms of atomic mass units? All right, so if we take a look here, all our answers are given indulgence. Remember, a Dalton is the same thing as an atomic mass unit. We're going to start out with this given amount. So this is our given amount and it is our responsibility to get to the end amount. So we need to get to this end amount.
Now. Our given amount is 190.23g. And we have to get to our end amount in Dalton's, which is the same thing as AMU. Now in order to go from our given amount to our end amount, we have to utilize conversion factors. Now the conversion factor we're going to use here. Our first conversion factor is conversion factor 1. We're first going to do a metric prefix conversion. We're going to change grams to kilograms. We want to get rid of grams, so grams go here on the bottom, kilograms go on top. Remember, the coefficient of one goes on the side with the metric prefix, meaning 1K is 10 to the three.
Now that grams are on opposite levels, they cancel out and we'll have kilograms at the end. We had to change the kilograms because now we're going to say for conversion factor 2, our metric prefix above says that
1.66 × 10 - 27 kg = 1 AMUAnd remember, an AMU and a Dalton are the same thing. So now our kilogram numbers cancel out and we'll get our answer here as Dalton's. So what's going to be here? It's
190.23 10.33 / 1.6 × 10 - 27Remember, if something is written in scientific notation, to avoid any errors within your calculator, you should put it in parentheses.
If you do this correctly, what you'll get initially, well, what you'll get at the end is
1.15 × 10 26 Daltons or AMURemember, they're interchangeable with one another. So if we look at our choices here, which one matches up with that value? That would be option A. So here we're talking about conversion of grams to AMU or Daltons. This is called dimensional analysis. We start out with our given amount. We have to get to our end amount and to get there we utilize conversion factors.
Here we had to employ metric prefix conversion with conversion factor one and then use the metric use the conversion factor listed above for conversion factor 2. That takes us from kilograms to daltons or AMU. So if you're a little bit rusty in terms of this, make sure you take a look at our videos on dimensional analysis, because this is the basic setup for any dimensional analysis type of question.