ChemCollective-Virtual-Labs/C2/Density-of-Solids-and-Liquids/English-timed

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Time Narration
00:01 Welcome to this tutorial on Density of Metals and Liquids using Vlabs.
00:08 In this tutorial, we will learn to determine, Densities of Metals and liquids.
00:14 To follow this tutorial you should be familiar with, ChemCollective Vlabs interface.

If not, for relevant tutorials please visit our website.

00:26 Here I am using, Mac OS version 10.10.5

ChemCollective Vlabs version 2.1.0

00:36 Java version 8.
00:39 Here I have opened a Vlabs window.
00:43 Click on File menu and select Load homework option.
00:48 Select Molarity and Density from the list.
00:52 Double-click on Metals Density Problem from the sub-menu.
00:57 Go to Problem description in the Stockroom explorer.
01:02 Pause the video to read the problem and then resume again.
01:07 Problem states that you have 3 unlabeled bottles with metallic powder.

You need to identify the metals in the bottles.

01:17 The metal densities are given in the problem description.

We will use Archimedes' Principle to find the densities of metals.

01:28 An object when immersed in water will displace water.

The displaced water will be equal to its volume.

01:38 Different metals have different densities.

Hence, different metals of the same weight have different volumes.

01:47 A metal that is less dense will displace more water than a denser one.
01:53 Switch to Workbench
01:56 Double Click on Metal 1, Metal 2, Metal 3 to add them to the Workbench.

Double click on water icon.

02:06 Click on Glassware icon.

Select Graduated Cylinders.

02:12 From the sub-menu select 25 ml Graduated Cylinder.
02:17 We need three 25 ml Graduated Cylinders for this experiment.
02:23 Right-click on Graduated Cylinder.
02:26 Context menu opens.

Using Duplicate option make 2 copies of the Graduated Cylinder.

02:34 Drag and bring the Graduated Cylinders to the centre of the Workbench.
02:41 Label the Cylinders as 1, 2 and 3.
02:49 Let us drag graduated cylinder 1 to the water tank.
02:54 Notice that a red warning icon appears.
02:58 This indicates that procedure is incorrect.

Place graduated cylinder 1 aside.

03:06 The correct procedure is to drag water on to the graduated cylinder.
03:12 Change the transfer mode to Precise Transfer using Tools menu.
03:17 Type 10 in the Transfer amount input bar.

Click on pour.

03:23 10 ml of water is transferred into the graduated cylinder 1.
03:29 Likewise transfer 10ml of water into graduated cylinders 2 and 3.
03:37 Move the water tank to a different place on the Workbench.
03:41 Click on Select Tools menu, from the list, select Scale.
03:47 Drag the Scale to a convenient position on the Workbench.
03:51 Again click on Select Tools menu, from the list select Weighing Boat.
03:57 We need three Weighing Boats for this experiment.

We can also use short-cut keys, to copy and paste.

04:06 Click on Weighing Boat.

Use Ctrl-C to copy and Ctrl-V to paste.

04:13 Drag and bring the weighing boats to the centre of the Workbench
04:19 Label the Weighing Boats as 1, 2 and 3.
04:24 Place weighing boat 1 over the scale.

Click on TARE button on the scale.

04:31 Drag Metal 1 over to weighing boat 1.
04:36 Type 50 in the Transfer Amount(g) input bar

Click on Pour.

Place the bottle aside.

04:44 Remove the weighing boat from the scale.

Place weighing boat 1 over the graduated cylinder 1.

04:52 Type 50 in the Transfer Amount input bar .

Click on Pour.

04:58 Observe the level of water in the graduated cylinder.

It has risen by 5 ml.

05:06 Keep the weighing boat 1 aside.
05:09 Now, Place weighing boat 2 on the scale.

Click on TARE button on the scale.

05:16 Drag Metal 2 over weighing boat 2.
05:20 Type 50 in the Transfer Amount(g) input bar.

Click on Pour.

05:26 Place the bottle aside.
05:28 Remove the weighing boat 2 from the scale.

Place weighing boat 2 over the graduated cylinder 2.

05:36 Type 50 in the Transfer Amount(g)input bar.

Click on Pour.

05:42 Observe that the water level in the cylinder has risen by 4 ml.

Keep the weighing boat 2 aside.

05:51 Similarly, weigh 50 grams of metal 3 using weighing boat 3.
06:00 Place weighing boat 3 over the graduated cylinder.
06:04 Type 50 in the Transfer Amount(g) input bar.

Click on Pour.

06:10 Water level in the cylinder has risen by 2.5 ml.

Keep the weighing boat 3 aside.

06:18 This slide shows the density calculations for the metals.

Calculate the densities using the formula: Density= mass/volume.

06:29 Experimental density of Metal 1 is 10 which corresponds to Silver.
06:35 Metal 2 is 12.2 which corresponds to Rhodium.
06:40 Metal 3 is 20 which corresponds to Platinum.
06:45 Repeat the above experiment with different metal weights (30 g and 40 g).

Tabulate and analyse your results.

06:56 Lets proceed to the liquid density problem.
07:00 Let us add a new workbench.

Click on File and select New workbench option.

07:08 Click on the workbench.
07:10 Go to File menu and select Load homework option.
07:14 Select Molarity and Density from the list.
07:18 Double-click on Liquid density problem.
07:22 Double-click on problem description in the stockroom explorer.
07:27 Pause the video to read the problem statement.

Resume after reading.

07:33 The problem states that there are two compounds of A-1 and A-2.
07:38 One of the liquids is a preservative, other liquid is not a preservative.

The preservative has higher density.

07:48 Our aim is to find the liquid containing Preservative.

For this we need to measure densities of A-1 and A-2.

07:58 Switch back to Workbench
08:02 Double-click on compounds A-1 and A-2 to add them to Workbench.
08:08 Obtain a 100ml volumetric flask from the glassware option.
08:14 We need two 100ml volumetric flasks for this experiment.
08:20 We can make a copy using Duplicate option.
08:24 Drag and bring the flasks to the center of the workbench.
08:30 Label the flasks as A-1 and A-2.

We can rename by pressing F2.

08:39 Click on Select tools icon.

Select Scale and add it to the Workbench.

08:46 Place the volumetric flask A-1 on the scale.

Click on TARE button.

08:52 Transfer 100ml of Compound A1 to flask A-1 by Precise Transfer mode.
09:01 Note the mass from the scale.

Scale reads 126 g.

09:08 Note this value. Place the flask A-1 aside.
09:13 Remove Volumetric flask from the scale.
09:17 Next place flask A-2 on the scale, click on TARE.

Pour 100 ml of Compound A-2.

09:29 Scale reads 85 g.

Note this value.

09:35 Experimental results are tabulated on this slide.

Calculate densities using the formula: Density=mass/volume

09:47 Observe that density of Compound A-1 is more than Compound A-2.

Therefore Compound A-1 contains the preservative.

09:57 Let's summarize.

In this tutorial we have learnt to measure,

Densities of silver, rhodium and platinum using Archimedes' Principle.

10:09 Densities of liquids with unknown concentration.
10:14 For the assignment.

Open default lab setup window.

10:19 You will find many stock solutions.

Find density for a few solutions of your choice.

10:28 The video at the following link summarizes the Spoken Tutorial project.

Please download and watch it.

10:35 The Spoken Tutorial Project team: conducts workshops using spoken tutorials and

gives certificates on passing online tests.

For more details, please write to us.

10:48 Please post your timed queries in this forum.
10:52 Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India.

More information on this mission is available at this link.

11:03 This tutorial is contributed by Snehalatha Kaliappan and Madhuri Ganapathi from IIT-Bombay.

Thank you for joining

Contributors and Content Editors

PoojaMoolya