names 1 inch + Black Vis-à-Vis Black Sharpie

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1 Types of Covalent Compounds: Polar and Nonpolar If you ever had a piece of paper get wet, you ve noticed that the ink making up the lines of the paper or the ink from your carefully collected notes travel through the paper with the water. You also know that there are inks that don t travel with water, or even soap, if you ve tried to get permanent marker off your clothing. The reason for this is the attraction water has for certain things and the non-attraction water has for other things, like wax. In this investigation inks will be separated into the different dyes that they are made of and then those dyes will travel through a paper towel. By observing the changes in the way the dyes spread when exposed to different liquids, you will be able to make a conclusion about the polar and non-polar nature of the dyes in the different pens. Procedure: 1. Put your names on the paper towel in pencil at the top left. 2. Using a pencil and a ruler make a neat table on a piece of paper towel. See the template at the lab station. Make 7 columns that are 1 inch or more wide (about the width of a ruler) from the top of the towel to its bottom (vertical lines). Make 9 rows with the pencil of the same width. 3. Label the columns using a pencil starting with the second column! with these different solvents: (A) water, (B) isopropanol (rubbing alcohol), (C) vinegar, (D) ammonia, (E) nail polish remover with acetone, (F) nail polish remover without acetone. 4. In the first column on the paper, use pencil to list the types of markers you will be using: (A) black pen, (B) black Sharpie pen, (C)black water-soluble marker like a Crayola marker, (D) purple Crayola marker, (E) brown pen, (F) green pen, (G) Marker 7 (use what is on your table), (H) Marker 8 (use what is on your table) 5. To fill in the spaces for the table you will be making a circle using the appropriate pen. Leave a opening that is about a 1/4 inch or 4 mm see examples on the page on your lab station. It is better to have a larger circle than a smaller circle. It may be easier to make a circle with 2 half circles: names 1 inch + Black Black Sharpie, since the towel is not easy to draw on. 6. Place the blank piece of white copy paper beneath the paper towel before adding the liquid to keep the towel clean from contamination on the table. 7. In each circle in the second column labeled water add ONE drop of water in the empty center of each circle of all the different pens. READ This: The best method is to make a drop on the bottle tip or pipet tip and then place the drop onto the paper towel and let the liquid be absorbed into the paper. If the drop falls from the dropper to the the paper it often misses the center. 8. After the drop of water spreads out, add a second drop to each circle if the spreading circle is not close to the square marked in pencil. 9. Now repeat with the different solvents one at a time. Add one drop and after the liquid has spread out add a second drop if necessary. 10. Clean up your materials and return the markers to the bag. Water Isopropanol using ( ) marks dropper

2 Use Pencil!!! to make the borders and write the names! On paper towel create this chart names 1 inch + Water Isopropanol Vinegar Ammonia Nail Polish (with acetone) Nail Polish (no acetone) Black Black Sharpie Black Marker, Crayola Purple Crayola Marker Brown Green Marker 7 Marker 8

3 Types of Covalent Compounds: Polar and Nonpolar - Questions Terms: Solvent is the liquid moving the inks; it dissolves the dyes in the ink so they travels with the liquid. Solute is the substances that are dissolved; the dyes in the ink are solutes. Ink is the liquid coming out of the pens; the ink contains different color solutes that are dyes. Dyes are the different solutes of an ink; for example, orange ink may be made from both yellow dye and red dye. Questions : From the two or three choices in the parentheses write the correct choice in the blank. 1) Answer these questions about the black Sharpie marker. a. The black ink in Sharpie permanent marker (does or doesn t) dissolve in water since the ink does not move with a drop of water. b. We know water is polar and that only polar compounds will dissolve in water. Since the dye in the ink do not dissolve in water then the dyes are (polar or nonpolar). c. The Sharpie ink does moves in the isopropanol and both nail polish removers, so these solvents (or liquids) must be (polar or nonpolar). The Sharpie ink shows only one moving color so there is only (zero, one, or two) dyes in the ink. 2) Check your answers to #1 Black ink in the permanent marker does not dissolve in water. Since water is polar and the ink does not dissolve then the ink is nonpolar. The nonpolar ink moves in isopropanol so the isopropanol is a nonpolar solvent. Since there is only one color visible, there is only one dye in the ink of the permanent marker. 3) Answer these questions about the black Crayola marker. a. The black ink in Crayola washable marker (does or doesn t) dissolve in water so it is (polar or nonpolar). b. The Crayola washable ink (moves or doesn t move) a smaller distance in isopropanol and the nail polish remover with acetone which are (polar or nonpolar). c. There are two colored dyes visible in water when using the black Crayola marker. (write a descriptive color) is on the outside of the circle and (write a descriptive color) is on the inside. This means the light blue dye is a more (polar or nonpolar) dye, and the black dye is a more (polar or nonpolar) dye. More questions on the back side

4 4) Answer these questions about the black Vis à Vis a. The black Vis à Vis pen has several dyes in the ink. The dye that moved to the outside of the circle in water was (write a descriptive color). This dye was a molecule that was (polar or nonpolar). b. Another dye that moved far with the water was (write a descriptive color). This dye was a molecule that was also (polar or nonpolar). c. In isopropanol both dyes (also or did not) move well, this is because the dyes are (polar or nonpolar) and the solvent isopropanol is (polar or nonpolar). 5) For the brown or green Vis á Vis, describe the movement of two dyes that shows that one is polar and the other is less polar (or nonpolar). Use the previous sentence frames to help you construct your argument. 6) The movement of the dyes in the different liquids can also be used to determine the polarity of the liquids. Compare the movement of the dyes of the brown or green Vis á Vis in water and in the two nail polish removers to determine if they are polar or nonpolar. Use the previous sentence frames to help you construct your argument.. 7) Polarity is a characteristic of the unequal distribution of electrons in a molecule. Name & describe types of intermolecular attractions between polar compounds and between nonpolar compounds.

5 Chromatography Chromatography is a broad class of analytical techniques used by chemists to isolate the components of a mixture by physical means (without changing the substance into a new substance). Types of chromatography include: gas chromatography, high pressure liquid chromatography, reverse-phase chromatography, thin layer chromatography, and more. Even gel electrophoresis used to separate strands of DNA is based on using differences in physical properties to separate components of a mixture. In paper chromatography, the type of chromatography you will use, a very small amount of a mixture is placed on a piece of paper. The mixtures we use will be the different inks in a pen. A green pen might have inks of yellow, blue, and green. With the a drop of ink on the paper, it is placed in a liquid, which is absorbed and travels up the paper. Inks in the mixture that dissolve in the liquid will travel with the liquid up through the paper. Also the paper itself will attract the inks and hold them in place. As a result of the solubility and the adhesion of the paper the different inks travel up the paper at different rates. In this lab you will separate the different inks in different pens using different solvents. Procedure 1. From the experiment where you added different liquids to different pens, choose two types of pens that will separate into at least 2 different inks (if you make an inappropriate choice you will have to use a third pen). You are going to use two of the liquids (but not water): one that dissolves like water and one that does not dissolve like water. 2. Get four pieces of chromatography paper. At the very top of the paper and in pencil, write initials and period, the type of pen you chose, and the liquid you will put the paper into. Each pen will go into each of the liquids cm or a bit more from the bottom make a line parallel to the bottom edge. (1 cm is about as wide as the picture of the paper to the right.) 4. The cut the bottom to make a triangle with its top cut off like the figure to the right. Use the pencil line to mark the end of the triangle. 5. Fold the paper down the center lightly so it s more rounded than creased. initials period pen ID liquid ID 6. In the center of the paper and on the pencil mark, place a dot of ink from the chosen pen to lightly transfers ink to the paper. See the figure to the right. A large smudge of ink will not work very well. 7. Add less than 1 /2 cm of one of the liquids you have chosen to a vial. The pencil line must not go below the liquid s surface or the ink will dissolve away from the paper. 8. Place the rounded paper into the vial with the liquid and let the paper touch the liquid and the bottom of the vial. The paper cannot touch the side of the vial. 9. The paper will stay in the vial until the liquid has been absorbed at least half way up the paper. 10. While you are waiting, repeat with the other liquid, and then with the other pen in both liquids. So you have a total of four trials. 11. When you remove the paper, tape it to a surface so it can dry without laying down on a table or a piece of paper.

6 Measure Rf values and Record in a Table for each Pen/Solvent combination. Rf is a ratio between the distance the solvent travels and the distance the chemicals travel (the colored ink). Using a ratio lets you compare the relative movement of ink without worrying about having the ink and liquid travel exactly the same total distance. For example in the picture to the right, the liquid (or solvent) travels 6.0 cm from the pencil mark and the pigment #1 travels 5.0 cm from the pencil mark This gives an Rf value = 5/6 or Record your Results Make a pencil circle around each major color (no more than 3). Label each ink for a pen as 1, 2, or 3 each pen Choose the upper center of the smear Distance Solvent Travels 6 cm Make a table to record the Rf values of the different inks of the different pen / liquid combinations. Record (1) the name of the pen and liquid, (2) number of the ink 1, 2, or 3 (3) a color for the ink be specific with the name of the color: teal, lime, olive, etc. not just green, (4) the ink measurement and the liquid measurement ratio, and (5) the decimal calculation of the Rf value. For Example RoseArt Pink in Isopropanol #1 light magenta 5cm/6 cm Rf = 0.83 The table will have the data for all four of your trials. There is enough space below for a neat table. Note that some inks travel all the way to the top. These inks have an Rf = 1.0. Some inks do not move from the spot. These inks have an Rf = 0.0. initials, period pen Tape your dry chromatography papers to the data table of one partner s lab, but ID all members of the group by using arrows, labels etc. near the taped paper. Distance Pigment #1 Travels 5 cm

7 Questions use complete sentences and no points without an explanation for your answer. Water and oil (or water and hexane) are two substances that don t mix when shaken. The water molecules have a strong attraction to each other that is due to their polar nature. A polar molecule is one which has a shift in electron density due to the uneven bonding geometry of the atoms and the different electronegativities of the atoms that draw the electrons towards the most electronegative atom (oxygen in this case). The strong attraction of the water molecules exclude the oil particles. Molecules that dissolve in water are attracted to water and mix with the molecules to make a clear solution. Ions, which have a charge, are also attracted to water because the shift in electron density in water makes the water molecules partially positive and partially negative. Molecules like oil and hexane that are nonpolar will dissolve in each other usually. So oils can be removed from your hands by rubbing them with gasoline. Spice flavors that do not dissolve in water will dissolve in oil, so we use oils and fats in cooking to help increase the flavor of our food. These observations can be summarized with the phrase like dissolves like. A substance that dissolves another substance is called the solvent (water is a common solvent), and the substance that is dissolved by the solvent is called a solute. 1. From your paper chromatography strips, state which one ink in one of the pens is polar. Use evidence from the experiment to justify your choice by identify the solvent and the Rf value of the ink. (If the paper chromatograph you are referencing is with someone else s paper tell me where to find the evidence by stating who has turned in the paper). 2. From your paper chromatography strips, state which of one of the inks is not polar. Justify your choice by compare the ink s movement (use Rf values) in both the water-like solvent and the alternative solvent. 3. Soaps and detergents are used to dissolve oils and stains that resist dissolving in water. This is a common simple detergent molecule. Label the part that dissolves oils and other nonpolar molecules and label the part that dissolves in water. 4. Draw a dark circle for a nonpolar stain and draw many SO4 (for detergent molecules) around the stain. Explain how a detergent works to remove nonpolar substances by using water. Refer to your drawing and use the both the words polar and nonpolar" at least twice in your explanation.