Activity 6: States of Matter and Intermolecular Forces
To
begin this activity, review the Content Slides in D2L on States of
Matter and Intermolecular Forces. We are all familiar with the states of
matter (solids, liquids and gases) for many substances. In the First
Activity we explored these states of matter for water. In Activity 6, we
would like to take our overall understanding of states of matter to the
molecular level. We will use the States of Matter simulation at http://phet.colorado.edu/ .
There are two key characteristics of molecules that determine their
state of matter. The first one is the temperature of the matter, and the
second one is the intermolecular forces (how well atoms/molecules stick
to one another) between atoms and molecules.
One of the first
things to think about here is temperature. Temperature and thermometers
have a very similar relation to speed and speedometers. For all
practical purposes, a thermometer is really a speedometer for molecular
speed or motion. At this site (another good NSF funded science education
site)http://www.visionlearning.com/library/module_viewer.php?mid=48 ,
is a good overview of temperature with a good image of the temperature
scales and conversions between different scales. Notice that the Kelvin
scale starts at zero and goes up from there. This is like our car
speedometer, in that at 0 Kelvin (K), molecular and atomic motions stop.
As the temperature rises, atoms and molecules begin to move faster and
faster.
The second thing to consider is the
intermolecular forces (attractions) that exist between molecules. In the
D2L content slides there are a few types of attractions described,
notice all of these are defined by the attraction that exists between
positive and negative charges. Water is a great example of a molecule
that has strong attractions that we call hydrogen bonding. It is this
strong attraction that makes water a unique molecule on our planet. It
turns out that the hydrogen atoms tend to be positive in charge, and the
oxygen atoms tends to be negative in charge.
Tasks to be completed for Acitivity 6
1. Convert 0°F, 32°F, 70°F, and 212°F to Kelvin
0°F = 225 Kelvin
32°F = 273 Kelvin
70°F = 294 Kelvin
212°F = 373 Kelvin
2.
Complete the Teaching Idea: States of Matter Simulation Lab by Kelly
Vaughan. Complete the lab worksheet as if you were a student, and then
post this on your blog. You can scan it or just take a picture of it.
3.
In the States of Matter simulation, choose the Solid, Liquid, and Gas
Tab at the top of the screen. Choose the water molecule and cool the
water to 0 K. Describe how the water molecules are aligned and attracted
to each other. Which atoms are attracted to which other atoms?
They are almost still and are only moving a tiny bit. The white molecules are more attracted to the orange molecules and they are almost forming a chain of a continuous white to orange line up.
4.
Switch to the Phase Changes Tab on the States of Matter simulation.
Notice how on the bottom right there is a small red dot that indicates
where the system is at as far as temperature, pressure and state of
matter. Play with the simulation to notice changes, notice that when you
push down the pressure can go way up and explode the box. On your blog,
report a temperature and pressure required to make oxygen a liquid.
This is sometimes how the oxygen exists in pressurized oxygen tanks,
perhaps like ones you may use to go diving.
10ATM
64K
5. List and describe at least two Science Standards that this activity addresses.
A.4.5 When studying a science-related problem, decide what changes
over time are occurring or have occurred
We did this in the experiments to see how different changes to the element affected water, oxygen, neon. We experimented with heating/cooling molecule to see there reaction, then with pressure. We saw how different elements were affected by the same things.
D.4.3. Understand that substances can exist in different states-solid,
liquid, gas
We talked all about the different states of matter and how they come to be and what temperatures they have to be at in order to maintain that state. We also went threw Kelvin, Celsius, and Fahrenheit.
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