Chem 105 Blog

Saturday, January 21, 2012

Activity 8

Activity 8: Exploration of Chemistry

For activity 8, students have a choice to explore other topics of chemistry presented in the PhET simulations.

Tasks to be completed:

1. Choose any Teaching Idea from any of the Chemistry Simulations (http://phet.colorado.edu/en/simulations/category/chemistry ) and post your results/data and/or answers on your blog.

C is the Answer.

The answer is D (B and C).


The answer is B.


The answer is B.


The answer is A.


The answer is water.

The answer is C.

2. Work with any of the Chemistry Simulations to create your own Teaching Idea. The criteria for this is as follows:

a. must identify and meet three (3) science education standards

b. must be original work

c. must be scientifically accurate and appropriate for the directed grade level.

Done by Michelle Counsell

For Fourth Grade

Need to use this website (http://phet.colorado.edu/en/simulations/category/chemistry )

Show all your work with screen shots for each problem

1.First go on this website and use the one called build a molecule.

2. Once it is open use the first kit to make water.

3. Then, go to the second kit by going in the lower right corner but the atoms. Then, at least make atoms make one more than the side says to. Fill in the side but you can show one more for extra credit.

3. Then do the last kit as well. Make the last three and fill the rest on the side. Then, you are done.

Friday, January 20, 2012

activity 5

Activity 5: Density

One of the most common attributes of chemical materials that we observe and feel on a daily basis is the density of materials. One of the things we notice in the structures of atoms, is that the atom is mostly space, with a small heavy nucleus and very light electrons orbiting the nucleus. So, how heavy something feels is related to how many protons and neutrons are in the nucleus of atoms that make up molecules. For example, aluminum is much lighter than iron. The "heaviness" of a material is quantified through a characteristic called density.

For this activity, and future ones, we will introduce the usage of simulations and gaming to aid in our understanding of chemical principles. The simulation package we will utilize can be found at this site:

http://phet.colorado.edu/

There are many of this types of things being developed on the web, I have found this one to be excellent for many reasons.

1. It is free! This is an activity supported by the National Science Foundation and many others to aid students and educators.

2. I find the interface to be easy and good for entry level science students and even advanced students. I have found that my 2nd grade son can use these simulations.

3. The science principles covered are very good, and the simulations are quite "real."

4. There is a developing support community for these simulations. For example there is a section for teachers in which there are pre-developed activities and a way to share your own activities.

For future educators and parents, I encourage you to encourage your future school districts to utilize these types of simulations in science education. Students tend to become engaged, and it can alleviate some of the costs and struggles of doing actual experiments in the classroom.

To complete Activity 5, complete the tasks below:

1. Run the Build an Atom simulation http://phet.colorado.edu/en/simulation/build-an-atom and build a neutral lithium atom and a neutral boron atom. Take a picture, or a screen shot, of these two atoms and place them on your blog. List the number of protons, neutrons and electrons for each. Also look up and post the density for each of the elements on your blog.

The number of protons, neutrons and electrons are all three. The density of the metal lithium is rho = 535 kg/m³ or rho = 0.535 g/cm^3.

The number of protons, neutrons and electrons is all 6. The density of the element boron is 2,340 kg/m³ or 2.34 g/cm³.

2. Define density and the equation for density and post on your blog.

According to http://wiki.answers.com/Q/What_is_density

3. Run the Density simulation http://phet.colorado.edu/en/simulation/density and complete one(your choice) of the prepared Teaching Ideas and post your results on your blog. The activity you choose should be one of the student intended activities.

PhET- Density Activity- Funsheet

Custom Section

Material	Mass (kg)	Volume (L)	Density (kg/L)	Does it Float?
Styrofoam	0.75 kg	5.00L	0.15kg/L	Yes
Wood	2.00 kg	5.00L	0.40kg/L	Yes
Ice	4.60 kg	5.00L	0.92kg/L	No
Brick	10.00 kg	5.00L	2.00kg/L	No
Aluminum	13.50 kg	5.00L	2.70kg/L	No

1. In the custom setting, choose the ‘My Object’ option in the material drop down box. Set the mass of your object to 4 kg. Adjust the volume to find the minimum volume needed to make the object float.

Volume_________________ Density__________________

2. How does the density of a large piece of aluminum compare to a small piece?

Same Mass Section

Material	Mass (kg)	Volume (L)	Density (kg/L)	Does it Float?
Blue	5.00kg	5.00L	1.00kg/L	Yes
Yellow	5.00kg	2.50L	2.50kg/L	Yes
Green	5.00kg	400L	1.25.kg/L	No
Red	5.00kg	1.25L	0.80kg/L	No

Same Volume Section

Material	Mass (kg)	Volume (L)	Density (kg/L)	Does it Float?
Blue	6.00 kg	5.00L	1.20kg/L	No
Yellow	8.00kg	5.00L	1.60kg/L	No
Green	4.00kg	5.00L	0.80kg/L	Yes
Red	2.00kg	5.00L	0.40kg/L	Yes

3. Looking at the data on the previous page, what must be true about the density of

an object in order for it to float?

The density must be less than one.

Same Density Section:

4. Calculate the density of the blue object in this section.

Mass ___4.00__________ Volume____4.00___________ Density________1.00kg/L________

5. Explain why both the yellow and red objects float when they have different sizes.

It is all about the equation and makes it so the density is less than one.

Mystery Section:

6. Before you start, pick an object that you think will float. _______ E____________________

Pick an object that you think will sink. __________ C

Material	Mass (kg)	Volume (L)	Density (kg/L)	Does it Float?
A	65.14	3.38	19.27	No
B	0.64	0.64	1.00	Yes
C	4.08	4.08	1.00	Yes
D	3.10	3.10	1.00	Yes
E	3.53	1.00	3.53	No

7. In the Custom section describe the difference between how Styrofoam and ice

floated. Also explain why you think this is the case?

The Styrofoam was high above the water and the ice was deeper but they both floated and this is the case since their density was less than one.

8. In the Same Mass Section discuss what was interesting about the blue object’s behavior in the water.

It floated one time and sank the other just because the equation was altered enough so that it sank or floated.

9. In the Mystery Section, click on the “Show Table” button. What is the most dense

object on the list? Write its density as well.

The show table was not an option on this simulation.

10. List something you learned from this activity.

I learn that if the density is less than one it floats and that just because it is small does not mean it will float.

4. Complete the Mystery Blocks activity on the Density simulation. Post on your blog the data you collected (mass, volume, and density) and the identification of the material and the known density.
It was done in the data above.

5. Identify and post on your blog the Science Standards that could be met through these activities completed in Activity4

B.12.4 Show how basic research and applied research contribute to new discoveries, inventions, and applications

A.12.4 Construct arguments that show how conflicting models and explanations of events can start with similar evidence

C.12.3 Evaluate* the data collected during an investigation*, critique the data-collection procedures and results, and suggest ways to make any needed improvements

Activity 7

Activity 7: Acids and Bases

Water is everywhere! So, lets spend one more activity learning about one of the key aspects of water. Water has the ability to dissociate (break apart from HOH (or H₂O) into H+ ions and OH- ions). We refer to solutions with lots of H+ ions as acids and solutions with lots of OH- ions as bases. By adding chemicals with H+ ions acidic solutions can be made. By adding chemicals with OH- ions basic solutions can be made.

Activity Tasks:

1. Review the Content Slides Acids and Bases on the D2L site.

2. Complete the Teaching Idea “Concept Questions for Chemistry using PhET” posted by Trish Loeblein on the pH Scale simulation at PHET (http://phet.colorado.edu/en/simulation/ph-scale). On your blog post the answers with your scientific explanations from the “Clicker Questions pH Scale” posted by Trish.

(If it is highlighted in yellow then it is the answer to the question.)

Describe image of gases using words and diagrams

1.How gases are distinguishable from a solid or liquid

Gas: A gas is a substance which takes the shape of its container and expands to completely fill it's container. There are several types of gases with slightly different behaviors. These are ideal gasses, real gasses, super critical fluids, plasmas and critical opalescent materials.
Ideal Gas: Ideal gasses (sometimes called perfect gases) refer to the behavior which gasses approach as the pressure nears zero. This behavior is described mathematically by the ideal gas law. Although no gas behaves exactly as an ideal gas, many substances come very close to ideal behavior at atmospheric pressure and most behave ideally at very low pressures.
Real Gas: Most molecules attract one another until they come very close together, when they become repulsive. This attraction is due to the electrostatic interactions between the two molecules. These interactions are often categorized into dispersion forces, van der Waals forces, hydrogen bonding and dipole-dipole interactions. The repulsion between molecules at very close distances is due to the repulsion between the nuclei of the two molecules. These forces give rise to relationships between the pressure, temperature, volume and quantity of a substance which do not exactly obey the ideal gas law. Gasses under physical conditions which give non-ideal behavior are called real gasses.

2.How the particle mass and gas temperature affect the image.
Molecular diffusion, often called simply diffusion, is the thermal motion of all (liquid or gas) particles at temperatures above absolute zero. The rate of this movement is a function of temperature, viscosity of the fluid and the size (mass) of the particles. Diffusion explains the net flux of molecules from a region of higher concentration to one of lower concentration, but it is important to note that diffusion also occurs when there is no concentration gradient. The result of diffusion is a gradual mixing of material. In a phase with uniform temperature, absent external net forces acting on the particles, the diffusion process will eventually result in complete mixing.

3.How the size and speed of gas molecules relate to everyday objects
It effects how a lot of things react to one another.

1. There are 2 balloons in a room. They are identical in size and material. One balloon is filled with air and the other balloon is filled with Helium. How does the pressure of the air balloon compare to the pressure of the Helium balloon. The pressure in the air balloon is

A. less B. equal C. greater

2. How does the pressure in the Helium balloon compare to the pressure of the air in the room? The pressure in the Helium balloon is

A. less B. equal C. greater

3. How do the number of air molecules in the air balloon compare to the number of He atoms in Helium balloon?
The number of air molecules is

A. less B. equal C. greater

4. How does the average speed of the Helium molecules compare to that of the air molecules?
The average speed of the He molecules is

A. less B. equal C. greater

Look at the animation of the particles bouncing around in the volume. Describe what visual information you can use to get a sense of the pressure that the gas particles are exerting on the walls. Pressure is also lost with movement.

Why does the pressure reading vary with time?
Pressure can lessen over time and it will do this unless it is in a vacuum.
What visual cues are associated with an increase in pressure?
According to the state equation
pv=nrt
p=pressure
v=volume
n=number of moles
r=gas constant
t=temperature.
This means the volume will be bigger as well and this means it will be bigger.

p and v are inversely proportional; as p increases, v decreases, as v increases, p decreases.

5. What will happen to the pressure if temp is held constant and the volume is decreased?

A.Pressure goes up because more collisions

B.Pressure goes up because more collisions are happening, but same force per collision

C.Pressure goes up because more collisions are happening, and increased force per collision

D.Nothing because pressure is only related to molecular speed

6. You are flying from Denver to Boston, and you bring along a ½ full bottle of shampoo that was well sealed before you left Denver. You land in Boston and proceed to your hotel. The number of air molecules within the shampoo bottle:

A. has decreased

B. has stayed the same

C. has increased

7. If the walls of the shampoo bottle are strong and rigid so that the bottle has the same shape as before you left, how does the pressure of the air inside the bottle compare to the pressure of the air in Denver?

A.less than

B.equal to

c.greater than

activity 6

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=255.37 Kelvin

32°F=273.15 Kelvin

70°F=294.26 Kelvin

212°F=373.15 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?

As you can see in the picture they are close together and some oxygen are touching but mostly they are touching the hydrogen. There are no hydrogen touching.

  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.

  5. List and describe at least two Science Standards that this activity addresses.

A.12.3 Give examples that show how partial systems, models, and explanations are used to give quick and reasonable solutions that are accurate enough for basic needs
I choose this one because the program had us use models that gave us a quick and reasonable solution that helped us see things like how water reacts to heat.

D.12.1 Describe* atomic structure and the properties of atoms, molecules, and matter during physical and chemical interactions*
I choose this one because this helps describe water and water is a bunch of molecules and we got to see how they change physical when heating and cooling it.

Wednesday, January 11, 2012

Activity 3

Now that we have some familiarity of atoms, Activity 3 explores how elements come together to make molecules.

In brief, the electrons that surround elements interact in a good way with electrons around other elements to create chemical bonds. These chemical bonds are what hold atoms together to form molecules. Molecules are the most common form of chemical substances that we experience everyday in our lives. If you go to Tylenol on wikipedia there is a good example of information on the molecule and the chemical structure of Tylenol. In the upper right of the page there is a structure called a Ball and Stick model. This model represents atoms that are held together by chemical bonds. In this model (which is quite common for chemistry) the black balls represent carbon atoms, the white balls represent hydrogen atoms, the blue balls represent nitrogen atoms, and the red balls represent oxygen atoms. Notice that it is possible to have 1 or even 2 bonds between some of the atoms. The other image is called a Kekule Diagram. This is the short-hand method that scientists use to draw molecules. It is very common for scientists to not indicate the carbon and hydrogen atoms since these are so common in molecules it becomes quite tedious! So it becomes necessary to understand that the Kekule structures are short-hand notation for the more accurate Ball and Stick model. The other common information needed for molecules is the molecular formula (this is the count of each type of atom in the molecule) and the formal chemical name. While in wikipedia on Tylenol, if you click on acetominophen or paracetamol you come to a page that has the detailed chemical information on this common drug. On the upper right is the same images. Under the images you will notice the systematic or IUPAC name. This is the name that scientists call this molecule. Also on the right you will notice the detailed chemical properties for this molecule, one of which is the formula, C₈H₉NO₂. So, in Tylenol there are 8 carbon atoms, 9 hydrogen atoms, 1 nitrogen atom and 2 oxygen atoms.

For this activity students are to explore the web and find chemical structures and names for everyday molecules. Remember Wikipedia tends to be a great resource for this info!

Questions/Activities:

1. Post a picture of three 3-dimensional Ball and Stick molecular models(choose your three favorite molecules) that you have created with common items around your home.

Also post a molecular structure image(image from the web, of either a Kekule Structure or a Ball and Stick Model) and the IUPAC name of the molecule.

Dihydrogen monoxide or Water

Methane

ammonia

2. Post an image from the web, the chemical systematic (IUPAC) name, common name, and the molecule formula for 20 chemicals that you use or eat. Explore the ingredients of things like cosmetics and foods.

1.rock salt, sodium chloride, NaCl,

2.alum, aluminum potassium sulfate,KAl(SO4)2•12(H2O)

3.baking soda, sodium bicarbonate, NaHCO3

4.banana oil (artificial), isoamyl acetate,(CH3)2CH(CH2)2CO2CH3,

5.bleaching powder, chlorinated lime; calcium hypochlorite,

Ca(ClO) 2

6.chalk, calcium carbonate,CaCO,

7.cream of tartar , potassium bitartrate,

KC 4 H 5 O 6

8.oil of wintergreen (artificial) , methyl salicylate, C8H8O3

9.pear oil (artificial) ,isoamyl acetate ,C7H14O2

10.rubbing alcohol, isopropyl alcohol,

C 3 H 8 O

11.silica, silicon dioxide,

SiO 2

12.table sugar, sucrose,

C 12 H 22 O 11

13.talc or talcum magnesium silicate, Mg3Si4O10(OH)2

14.vinegar, acetic acid ,

C 2 H 4 O 2

15.vitamin C, ascorbic acid,

C 6 H 8 O 6

16.aspirin , acetylsalicylic acid,

C 9 H 8 O 4

17. Tylenol, Acetaminophen, C8H9NO2

18.MSG, Monosodium glutamate, C 5 H 8 NNaO 4

19.sugar, glucose ,C6H12O6

20.bleach, Sodium hypochlorite, NaClO,

3. Look over your molecules and the bonding characteristics, how many bonds does each of the following elements typically have? Carbon? Hydrogen? Oxygen?

carbon - 4,hydrogen-1,oxygen-2,nitrogen-3,phosphorus-3,sulfur-2

4. What does IUPAC stand for?

IUPAC is the International Union of Pure and Applied Chemistry.

5. As you explore ingredients, notice how everything around us is made up of chemicals consisting of atoms bound together into molecules. But what about companies that claim their products are chemical free! How can this be? Here is an example:

http://www.naturalhealthcareproducts.com/Cleaning-Products.php

Do a little web searching and propose what chemicals are actually in this product.

They are stating that it is all natural and it has not man made chemicals or harmful chemicals. Even though they do use "chemicals" but they don't use what most people would consider chemicals. This is why they can say this. These chemicals in this product are eucalyptus oil, chlorine scavenger, and anti-redeposition agent. None of those make me think of chemicals or sound harmful to the environment and they all come from the environment and therefore they are not man made chemicals.