Transcription
Welcome to the new Chem Collective Virtual Laboratory. This version is HTML5-based and will run on most devices. The stock remix floor is shown on the left, with menus in the problem name in the upper panels. Clicking on the problem name displays information about this activity and the sacrum explorer. Use the tabs at the top to select between reagents, glassware, and tools. Clicking on a group expands or collapses the items inside. To bring an item out of the stockroom, single-click on it. This puts the item on the desktop, and information about the item appears in the solution information panel. To return to the stockroom, click on the collapse stockroom panel at the top of the pane.
I'll get ready for a titration by using the glassware menu to get a burette. I'll also get an indicator and a sample of the unknown acid I'm going to titrate. When a flask is selected, you can view detailed information about it and the solution info panel on the left. The name of the currently selected flask is shown along with its volume. The table below shows the species in the solution along with their amounts. The amount can be shown in molarity, moles, and grams. The solution information panel also shows temperature and pH. The View menu and viewer configuration button allow you to toggle displays of additional information, such as the UV-Vis spectrum and a list of the solid species in the vessel.
To transfer solutions from one piece of glassware to another, drag the source flask onto the destination flask. Notice the flasks are now connected, and the transfer window is activated. The transfer window has three tabs: precise, significant figures, and realistic for each of the transfer modes in the virtual lab. To transfer a solution in precise mode, type the desired amount and click pour. Notice the updated information in the solution information panel. When your transfer is complete, click the X button at the top right of the transfer window or drag the flask support.
Next, I'll transfer a sample of the unknown acid solution to a new flask. To do this, I'll drag a 25 mL pipette onto the sample of unknown acid. Notice the pipettes have two transfer buttons: one for withdrawing solution into the pipette and one for pouring solution from the pipette. Here, I'll demonstrate the significant figures transfer mode by selecting the sig fig tab. For this mode, you can only transfer values appropriate to the glassware you are using. I will enter 25.00 and click withdraw. I can drag the pipette onto the destination flask. I'll type 25 again into the box and click pour. Notice the error when incorrect significant figures are used.
Finally, I'll add an indicator to my solution. This time, I'll demonstrate the realistic transfer mode by selecting the realistic tab. In this mode, solutions are transferred by holding down the pour button. Note that the longer the pour button is held down, the greater volume of solution is transferred. By right-clicking on a selected flask or through the Edit menu, you can perform a number of tasks on a flask, such as rename, duplicate, or change the thermal properties. Here, we'll rename the new flask and then make an additional duplicate copy as a backup.
We are now ready to perform our titration. We begin by dragging the burette onto the sample of unknown acid. For this example, we will use the precise transfer mode. When you perform the titration yourself, you may use any of the available transfer options or the one specified by your instructor. Notice how the volume, pH, and temperature change as the solutions are mixed. When you have finished with a piece of glassware, you can remove it by right-clicking and selecting remove. Additionally, you can select clear workbench by right-clicking on the workbench to remove all items.
We hope that you liked the new version of the virtual lab. Please email us with your comments or concerns.