 Okay, so for the last problem of the day, we'll do one of these integrated rate law problems. This one says, in the first order of reaction, A going to products, the initial concentration of A is 1.56 molar, and the concentration is 0.869 molar after 48.0 minutes. What is the value of the rate constant K in per minute? So in order to do this problem, the thing you really need to know is the integrated rate law for a first order reaction. So make sure you can recall it. So it's the ln natural log of the concentration of A initially divided by the concentration of A at time t, and that equals the rate constant times the time. So we have values for A0, that's given to us, A at time t and t. So what we're looking for is the rate constant. So all we need to do is rearrange that equation and then plug each other. So I'm going to isolate the variable K here. So K equals ln A0 divided by At, I'm going to divide all of that by t. Is that fine? Can you do that one? Can I raise this portion here? Yeah. Okay, so let's plug in everything. 1.56 molar divided by 0.869 molar, molar cancels out there, and on the bottom 48.0 minutes like that. So now I get out of your calculator, 1.56 divided by 0.869, take the ln of that, and then divide it by 48. And I get an answer of 1.22 times 10 to the negative 2, and look at your units per minutes, okay? Minutes to the negative, and that's what we were looking for, so any questions on that one? Yeah, again, I think the thing you want to remember on these problems is just the integrated rate law, and then it'll be fine.