Viewing Molecules

          In this activity you will be running software to view models of a variety of molecules.

Start the Rasmol molecular viewer (your teacher will tell you how).

Maximise the program to fill the screen, then select File>open and open the 'water' file. Water has the formula H2O. What you see is a model of the molecule - it can be viewed in 3 different ways by selecting 'Display' from the menu bar and then 'Wire frame'; 'Ball and stick' or 'Space Filling'

You can move and rotate the molecule by dragging it with the mouse; and zoom by pressing 'shift' (or upward arrow) and dragging with the mouse.

Draw diagrams, and answer questions carefully and clearly (in full sentences).

1. Under the heading 'A Water Molecule', neatly draw the 3 different diagrams of the water molecule, in colour, and clearly label the atoms in each case (ie hydrogen atom/oxygen atom)

2. Repeat the above procedure for carbon dioxide (CO2) and methane (CH4) [You must select file>close before opening a new file].

3. Which of the 3 types of model of the molecules do you think is closest to the actual appearance of the molecules?

4. Look at some of the larger molecules such as TNT, haemoglobin, caffeine and many more. Write down the name of the molecule and list the elements found in these substances.

Note: most of the colour codes are the same as for the smaller molecules you have already viewed. Blue spheres usually represent nitrogen atoms and yellow ones, sulfur.

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