Name _____________________ Inquiry – Questions – Hypothesis – Independent – Dependent – Controls – Control – Data Collection – Data Presentation - Data Analysis – Hypothesis supported, refuted, inconclusive-conclusions-new questions Lab Safety – Right to know – lab rules – MSDS – Bunsen burner Chemistry – Matter – Sources of Matter – Separation Techniques I. Chemiluminescence Glow Sticks – II. A student ask the question, does a glow stick used on a Halloween night last longer on a cold night? III. Materials Luminol 5 % Hydrogen Peroxide 0.10 M Sodium Hydroxide Thermometer Water at different temperatures Beakers Stop Watches IV. Procedures 1. a) Place 200 mL of room temperature water (approximately 20oC measured with an alcohol thermometer) in a 400 mL beaker b) Place 10mL of 5% hydrogen peroxide in test tube 1. b) Place 5 ml of .10 M NaOH(aq) in test tube 2. 2. a) Place test tubes 1 and 2 into the 400ml beaker filled with the 200 mL water at room temperature. b) Wait 5 minutes so that the 5 % hydrogen peroxide and NaOH (aq) obtain the temperature of the water. 3. a) Add 1.0 g of luminol to a test tube tube 3 b) Add 10 mL of 5 % hydrogen peroxide to test tube 3 c) Add 5.0 mL of .10 M NaOH(aq) to test tube 3, start timing with a stopwatch, and place in the 20oC water bath 4. Stop timing with the stopwatch when the mixture does not release visible light. 5. Repeat steps 1,2, and 3 at approximately 10oC, 30oC and 40oC. 200mL water Temperature 20oC 10mL 5% Hydrogen Peroxide 5 mL .10 M NaOH(aq) 1.0 g Luminol 10ml hydrogen peroxide NaOH(aq) V. Data 20o C – glow time = 63 seconds 11oC - glow time = 128seconds 29 oC - glow time = 31 seconds 42 oC - glow time = 14 seconds Reproducible results were obtained for multiple trials at approximately the same temperature ranges 1. What is the independent variable of the above experiment and how was it measured? The temperature of the reaction between the luminol, 5% hydrogen peroxide, and 1.0 M NaOH(aq) was the independent variable (it was manipulated in the Experiment) and was measured by an alcohol thermometer. 2. What is the dependent variable of the above the experiment and how was it measured? The dependent variable ( it responded to the change in temperature) was the glow time measured with a stopwatch. 3. What controls were performed in the above experiment? Why are controls needed? The volume of 5 % hydrogen peroxide, mass of luminol, volume of 1.0 M NaOH(aq), Container sizes. They were controlled in order to ISOLATE THE RELATIONSHIP between the DEPENDENT VARIABLE ( Glow time ) and the INDEPENDENT VARIABLE ( Temperature of reaction mixture ) 4. Create a graph that illustrates the relationships between temperature and duration of glow Title: 2pts Glow Time of the reaction between luminol, 5 % hydrogen peroxide as a function of temperature of reaction mixture. 120 100 1pt Glow Time In Seconds 80 60 40 20 0 10 20 30 40 1pt Temperature of reaction mixture in oC What can you conclude given the above data and graph? 5. a) Calcium carbonate is the active ingredient Tums Antacid tablets. What source of matter does calcium carbonate most likely come from and why? _____ 1pt a) plants d) crude oil / petroleum b) lakes and oceans e) rocks, minerals, ores c) air ii) Why? 2pts Calcium is a metal containing compound and is therefore it’s source is rocks, minerals, ores. Calcium carbonate is a mineral b) Plants are excellent sources of fibers such as cotton. A new fiber can be made from the polymer Poly Vinyl Alcohol can be used to replace cotton in hospital garments. It is useful because it dissolves in water about 200 oC. What is the source of matter Poly Vinyl Alcohol is made from? Why is this source usually used as a substitute for naturally occurring substances? ii)Why? 3pts Crude oil – Crude oil is formed from decaying plant and animal matter that has been exposed to heat and pressure for millions of years. Crude oil contains the same raw materials found in plants and can be used to synthesize substances that mimic those produced by plants and animals. Separation Techniques 6. Separates and saves substances based on differences in boiling points. Lowest boiling point substances are removed and collected first. ____ Distillation 7. Separates substances based on the relative affinity a substance has for the medium it is traveling through such as paper. ____ Chromatography 8. Separates the elements found in a compound based on a chemical reaction that occurs at the positive and negative poles of a power supply. ____ Electrolysis 9. Separates and saves substances based on their solubility differences _____ Filtration 10. Separates substances based on the differences in the density of liquids that do not mix ____ Separating Funnel A. B. C. D. E. F. G. H. Chromatography Centrifuge Electrolysis Filtration Separating Funnel Evaporation Magnet Distillation 11. 12. Which one of the following could be used to separate hydrogen from water? F 1pt Which one of the following can be used to separate and save the oils from the aqueous solutions found in citrus fruits because the oils have a lower density than the aqueous solutions. A 1pt 13. Which one of the following can be used to separate insoluble sediment from solution containing a soluble mineral. E – filtration 1pt 14. Which one of the following can be used to remove water from a mixture to determine the amount of dissolved substances found in the solution? B – evaporation 1pt A B C E D F 15. a) If your Bunsen burner produces a yellow sooty flame what can you do the change it to a blue flame? 2pts Increase fuel by adjusting the burner valve and then increasing the air intake by adjusting the burner valve. b) Which valve do you use to adjust the height of a flame? (The table valve or the burner valve) 1pt. Burner valve. 16. HCl (aq) is a known poison! It is dangerous. It is corrosive. The liquid and mist cause severe burns to all body tissues. HCl may be fatal if swallowed or inhaled. Inhalation may cause lung damage. Where can you find information about the substances such as HCl(aq) used in this class? 1pt. Material Safety Data Sheets What law informs workers in industrial work places of the risks associated with substances they Use or come in contact with? Right to Know Law 17. You are given an acid base indicator, a base and an acid. You know that the indicator is yellow in acid and blue in base. Explain how you can determine which solution is more concentrated and how many times more concentrated that solution is compared to the other solution. (4pts) 1. Add 1 drop of an indicator into a test tube and note the color 2. Add 3 drops of the acid to that test tube and note the color. 3. Add 1 drop of an indicator into second test tube and note the color 4. Add 3 drops of an indicator into that second test tube 5. Add 5 drops of indicator to a third test tube 6. Add 10 drops of acid to the third test tube. 7. Add drops of base until the indicator changes from the base color to the acid color. Record number of drops of base needed. 8. Add 5 drops of indicator to a fourth test tube 9. Add 10 drops of base to a fourth test tube. 9. Add drops of acid until the indicator changes from the base color to the acid color. Record number of drops of acid needed. 10. Repeat steps 5 to 7 three times and 8 to 9 three times. The following table can be used to determine the relative concentrations of the acid and base Indicator Drops acid and color of Drops of base added to change indicator acid mixture color of indicator from acid red to green base 5 drops of green indicator 10 – color red 12 – color green Indicator Drops base added – and Color Drops of acid added to change color of indicator from base green to acid red 5 drops of green indicator 10 – color – green 9 – color red Calculations - Conclusions If 12 drops of base are needed to change the indicator and 10 drops of acid from the acid Color to the base color then the acid is between 11/10 ( 1.1) and 12/10 ( 1.2 ) times more Concentrated. 11 drops is not quite enough base to neutralize the 10 acid and the 12 drops is more than enough base to neutralize the 10 drops acid If 9 drops of acid are needed to change the indicator and 10 drops of base from the base color to the acid color then the acid is between 10/9 ( 1.11) and 10/8 ( 1.25 ) times more Concentrated. 8 drops is not quite enough base to neutralize the 10 base and the 9 drops is more than enough base to neutralize the 10 drops base A column cartridge is composed of a polar stationary phase. Isopropyl alcohol is a relatively non-polar solvent. Water is a polar liquid. A maroon pigment is extracted using isopropyl alcohol. The pigment is then injected into the column cartridge and the maroon pigment stays in the cartridge and the eluent ( product) is clear. A 5 % water 95 % isopropyl solution is then injected into the cartridge containing the maroon extract. The column cartridge turns red and the eluent ( product ) is orange. A 25 % water 75 % isopropyl solution is then injected into the cartridge containing the red pigement. The column cartridge turns clear and the eluent ( product ) is red. What conclusions can you make given the above information about the maroon pigment. The maroon pigment is a mixture of orange and red pigments. The eluent after adding the 5 % water and 95 % isopropyl alcohol to the maroon mixture in the column’s polar stationary phase is orange and the eluent is red after adding the 25 % water 75 % isopropyl alcohol solution to the polar stationary phase after extracting the orange pigment. The column is clear after the second extraction indicator that the pigment contains two pigments. The orange pigment is more non-polar than the red pigment. It was extracted from the polar cartridge stationary phase with the more non polar mobile phase mixture of 5 % water and 95 % isopropyl alcohol. The red pigment is less non-polar or more polar than the orange pigment. It was extracted from the polar cartridge stationary phase with the more polar mobile phase mixture of 25 % water and 75 % isopropyl alcohol. 18. A solution of gold nitrate is obtained. Explain in detail using the following terms how the Gold can be extracted from the solution. Electrons, reduction, cathode, anode, oxidation, red (+) wire, black (-) wire, water, oxygen Hydrogen ions. Black lead – negative electrode – cathode - releases electrons Negative electrons attract the positive gold ions of the gold nitrate solution Gold metal forms as the electrons reduce the positive gold ions to metal atoms The nitrate ions migrate to the positive electrode At the positive electrode – red lead – anode water decomposes into oxygen, hydrogen ions, and releases electrons through the red lead. The oxygen of the water has Lost electrons and has undergone the process of oxidation.