This preview shows page 1. Sign up to view the full content.
Unformatted text preview: eriodic box”; I
will run this one in vacuo, however, since it often becomes difficult to see the molecule with a lot
of water molecules around it.
Step one is complete; the calculation has been set up. Now, step 2; run the calculation.
Go to “Compute” and “Molecular Dynamics”; Hyper Chem will remember your choices from
the previous step. For example, my MD will run using the AMBER force field. You will notice
there are more choices here, such as step size and time of simulation. Typically, the smaller the
step size and the longer the run, the more accurate the results, but the slower it will be. For our
purposes, I recommend simply choosing the results. You will see the isopropanal begin to dance
on your screen; this is a simulation of how the molecule can be expected to actually move, if we
could see it so clearly, in reality. Dakota State University Page 33 of 232 Using HyperChem General Chemistry I and II Lab Manual Now, aside from the really cool ways the molecule moves, there is not much more that
we need here today. However, while this simulation was running, there were certain properties
that were calculated as it ran. Although we don’t need them now, if you want to display these
properties (the third and final step of the sequence), go to “compute” and you will see several
options that were not available before (such as “properties” and “plot molecular graphs”). Feel
free to take a look at what is in these if you are curious. Dakota State University Page 34 of 232 Basic Laboratory Procedures General Chemistry I and II Lab Manual Basic Laboratory Procedures
Most basic laboratory equipment is made of glass so one can easily see what is happening
inside. When I think of the most common equipment, the beaker and the flask come to mind.
Beakers are probably
most commonly used;
their wide mouth and
spouts make it very easy
to transfer solutions from
one beaker to another.
The flask (or, to be more
precise, the “Erlenmeyer
flask”) is an excellent
choice to run reactions if
you do not plan to
frequently. The tapered
neck of the flask makes it
very easy to grab, hold,
swirl and manipulate.
Other pieces of
includes the scoopula
moderate sized amo unts of solids), the spatula (for smaller amounts of solid), The stirring rod
and the rubber policeman (on the end of a stirring rod, for scraping crystals out of beakers). For
this lab, we will replace the thermometer with a Pasco temperature probe. Rather than droppers,
we will use disposable pipettes.
The balance is used to determine the mass
of an object. Like so many other things today,
modern balances just continue to get easier to
use. At DSU, we use digital balances. The basic
operation of these balances is trivial; place your
object on the pan, and the mass appears on the
display. However, also like so many modern
devices, there are advanced features that may not
be so obvious. In this section, I will not only
Dakota State University Page 35 of 232 Basic Laboratory Procedures General Chemistry I and II Lab...
View Full Document