OTHS Academic Chemistry Lab Notebook

Transcription

1 Name Period 1 st Six Weeks OTHS Academic Chemistry Lab Notebook To raise new questions, new possibilities, to regard old problems from a new angle, requires creative imagination and marks real advance in science. -Albert Einstein-

2 Page Table of Contents Lab 1.. Safety Scavenger Hunt 5.. Proper Handwashing Technique 6.. Chemistry Equipment Lab Intro to Measurement Lab Separation of a Mixture lab Density Lab 14 Crime Scene Chemical Investigators 18 An Investigation Into Atomic Structure Would you like your own pair of goggles? Order from Flinn Scientific, Models AP3306 and AP3309 are both approved. Lab Protocol: Electronic devices are not appropriate in a laboratory setting and may not be used or in sight during labs. Lab safety rules must be followed at all times. Negligence (not wearing goggles or closed toe shoes), not following instructions, purposeful horseplay, and harmful behavior will not be tolerated in the lab. Clean-up: In a chemistry lab, students are expected to take care of the equipment and lab stations. Each lab period, 10 points are allocated for lab clean-up. If the lab is left in disarray, 10 points will be deducted from the lab grade. Lost notebooks: Students are given one lab notebook each six weeks. If lost, students may print labs from the course website, but 5 points will be deducted for each occurrence. Late labs: 1 day late= Maximum 75, 2 days late= Maximum 50, 3+ days late= zero Unless specified otherwise, violation of lab protocol will result in a 20 point deduction from the lab grade and/or a discipline referral to the student s grade level principal.

3 Name Date Period Safety Scavenger Hunt Lab Diagram: Find each of the following items in the lab. Sketch the item in its correct position in the lab, and place the number of each item on your sketch. 1. Student lab tables 2. Teacher demo table 3. Sinks (all) 4. Fire extinguisher 5. Fire blanket 6. Eyewash 7. Safety shower 8. Red emergency stop button for electricity 9. Fume hood (if applicable) 10. Goggle cabinet 11. Doors (all) FRONT OF ROOM BACK OF ROOM 1

4 Answer the following questions about safety in the lab. 1. Fire Extinguisher What kind of fire extinguisher do we have in the lab? (ABC or ABCD?) Would you use this to put out a small paper fire on top of your lab table? If not, what is a better option? Would you use this to put out an oil fire? Describe how you would activate the extinguisher to put out a fire. (What acronym helps you remember what to do?) 2. Safety Goggles If you wear glasses, do you need to wear goggles during lab? Why or why not? If you wear contacts, do you need to wear goggles during lab? Why or why not? If chemicals splash on your face and you are wearing goggles, should you remove the goggles? Why or why not? 3. Fire Blanket How do you get the fire blanket out of the box? What color is it? Would you use this to put out a small paper fire on top of your lab table? If not, what would you do? Would you use this if you spilled acid on your clothes? If not, what would you do? Would you use this if someone s clothes were on fire? If not, what would you do? What would you do if your clothes caught on fire? 4. Eye Wash How long should you wash your eyes if they are splashed with a chemical? If you were far from the eye wash station and chemicals splashed in your eyes, what else could you do? 2

5 5. Fume Hood What is the purpose of the fume hood? What kinds of chemicals should be placed in the fume hood? 6. Safety Shower Give 2 situations in which you would use the safety shower. If you needed to use the safety shower for one of the above reasons, and brownish water started coming out of it, what should you do? 7. Dilution Safety To dilute a solution means to add water, making it less concentrated. In chemistry, sometimes we need to dilute acids. In order to dilute an acid, should you pour acid into water, or the other way around? Why? 8. Cleaning Up When you are finished with the contents of a test tube, beaker, or flask, do you always dispose of the contents in the sink? Explain. When is it okay to dispose of solids in the sink? Why is it critical to immediately wipe up spills on the floor? For what kinds of spills are paper towels alone not adequate? At the end of lab after you have cleaned up, should you first take off your goggles and then wash your hands, or the other way around? Why? Is using hand sanitizer an acceptable way to clean your hands after a chemistry lab? Why or why not? 9. Minor Lab Mishaps If you spill a chemical, break a piece of glassware, or get a minor cut or burn in the lab, who must be notified? Why? If you get a minor burn in the lab, what is the immediate first aid treatment? If you get a minor cut in the lab, what is the immediate first aid treatment? 3

6 10. Heat Sources Locate the natural gas jets at the lab tables. Bunsen burners are gas burners that connect to the jets. They are a source of open flame. (Hot plates are also used as heat sources in chemistry labs, but they are not open flame devices.) If the turning lever (labeled GAS ) is perpendicular to the nozzle, is the gas on or off? If the turning lever is parallel to the nozzle, is the gas on or off? In order for the gas to work in the lab, the teacher must turn on the gas main. Even if the main is off, why is it a bad idea to play with the gas jets? (Ex. open and close the turning lever) If you have to heat a liquid that is volatile (vaporizes easily), should you use an open flame? Why or why not? 11. Chemical Information Find the SDS. These sheets are available for all purchased chemicals in our lab. This information is also available on the internet. What does SDS stand for? What are the sections on a SDS? Find the NFPA Diamond sheet. What is the purpose of the NFPA Diamond for a chemical? Label/color the diamond below and indicate what each rating means: Blue Red White Yellow Fire Drills/Fires Find the fire evacuation map on the wall. Trace both the primary and secondary exit routes on the lab diagram on page one. We are in the middle of a lab using Bunsen burners or hot plates, and the fire alarm goes off. What should you do? 4

7 Proper Handwashing Technique PURPOSE On average, 95% of people don t wash their hands properly. Good hand hygiene has been shown to stop outbreaks in healthcare facilities, reduce transmission of antimicrobial resistant organisms, and reduce overall infection rates. Hand washing is a primary safeguard against inadvertent exposure to toxic chemicals or biological agents. In the chemistry lab, it is important to wash your hands to prevent transfer of chemicals to more sensitive parts of the body. Always wash your hands BEFORE leaving the chemistry laboratory. PROCEDURE 1. According to your teacher s instructions, contaminate your hands. 2. View your hands under a black light. Diagram areas where chemicals are present on the hand labeled contaminated (below). 3. Wash and dry your hands as you normally would. 4. Look at your hands under a black light for a second time. Take note of areas missed and diagram the results on the hand labeled after washing normally (below). 5. Wash your hands for a third time according to the instructions at your lab station. Look at your hands under the black light for a third time. 6. Diagram the results on the hand labeled after washing properly (below). CONTAMNIATED After After washing washing normally properly QUESTIONS Determine whether the following is true (T) or false (F) 1. Jewelry should be removed before washing your hands. 2. Fingers do not have to be interlaced at any time when performing handwashing. 3. It is best to dry my hands on my jeans. 4. If I m leaving the lab to go to the restroom, I do not need to wash my hands first. 5. Wet your hands, apply soap, and create lather for 15 seconds using circular motion. 6. The most frequently missed areas are between fingers and at the ends of fingers. 7. Most people wash their hands correctly, so transmission of disease/chemicals is low. 8. The chemicals we will use in the high school chemistry lab are not dangerous; therefore properly washing my hands isn t important. 9. Scrub the back of each hand also, not just the palm. 10. If my eye itches, it is ok to remove eye goggles and rub it before washing my hands. 5

8 Name Date Period Chemistry Equipment Lab Identify each of the pieces of equipment and/or glassware on the lab tables a. j. b. k. c. l. d. m. e. n. f. o. g. p. h. q. i. r. Match the above equipment to its use: 1. Glass or plastic common sizes: 50, 100, 250, 400 ml; glass may be heated. 2. Wire frame with porcelain supports; used to support a crucible. 3. Glass tip with rubber bulb; used to transfer drops of liquid 4. Iron or nickel; used to pick up and hold small items 5. Porcelain (or glass); used to contain small volumes of liquid being evaporated 6. Porcelain; may be used to grind crystals and lumpy chemicals to a powder. 7. Glass or plastic; common sizes are 10, 50, 100 ml, used to measure accurate volumes; cannot be heated. 8. Glass; common sized are 100mL, 250mL; may be heated; used in titrations 9. Metal; used to hold or pick up small objects 10. Metal rod fixed upright in a heavy metal base; has many uses as a support 11. Glass, come in small, medium, and large sizes; may be used to heat chemicals 12. Made of metal; connected to a gas supply with rubber tubing; used to heat chemicals 13. Spring metal; used to hold test tubes or glass tubing 14. Glass; used to cover an evaporating dish or beaker. 15. Metal or porcelain; used to transfer solid chemicals. 6

9 Name Date Period Intro to Measurement Lab Objectives: To practice measurement skills and to understand the importance of significant figures in scientific measurement. Significant figures are the digits that make up a measured quantity, including one last estimated digit. Remember: Read what you know, and estimate one more. (Except for digital equipment) Station Measuring Device Object Interval (smallest division on equipment) Measurement (ex. 45.6) Unit (ex. ml) 1 Triple Beam Balance Beaker w/ marbles 2 3 Digital Balance (0.01 g) Beaker w/ marbles 400 ml beaker Green colored water n/a ml graduated cylinder 25 ml graduated cylinder 10 ml graduated cylinder Blue colored water Yellow colored water Red colored water 7 Buret Tap water 8 Thermometer Tap water Questions: 1. Explain the proper method for reading the volume of a graduated cylinder? 2. What are significant figures? How many sig figs are in the measurements above? Definition: Station: If you wanted to measure the volume of a sample of liquid to a high degree of precision, which instrument above would you use? Why? HINT: look at the intervals! 7

10 Measuring with Precision: Use the technique taught in class. Using the centimeter ruler above, read and record these measurements: 4. Point G = cm 5. Point A = cm 6. Point C = cm 7. Point I = cm 8. Read the volume of the graduated cylinder below: ml 8

11 Separation of a Mixture Lab Introduction The ability to separate and recover pure substances from mixtures is extremely important in scientific research and industry. Chemists need to work with pure substances, but naturally occurring materials are seldom pure. Often, differences in the physical properties of the components in a mixture provide the means for separating them. In this experiment, you will design and implement your own procedure for separating a mixture. The mixture you will work with contains salt, sand, and iron filings. All three substances are in dry, granular form. Objectives 1. Observe the physical properties of a mixture. 2. Relate knowledge of physical properties to the task of purifying the mixture. 3. Analyze the success of your separation methods. Materials Sample of mixture (sand, salt and iron filings) Beaker Erlenmeyer flask Graduated cylinder Hot plate Magnet Filter funnel Filter paper Stirring rod Safety Any procedure MUST BE APPROVED by the teacher before performing it to ensure that necessary safety measures are being followed. Goggles and aprons must be worn at all times. Procedure 1. Design a method to separate your mixture. Write the steps to your procedure in detail on the next page. For each step, include the reasoning behind your plan. Remember, a good laboratory procedure is easy to follow and allows someone else to copy your experiment exactly. 2. Obtain teacher approval for your procedure before going any further. 3. Obtain a sample of the mixture. Using the equipment you have available, carry out your procedure. Note your observations as you perform each step. 4. Using what you have learned during your procedure, fill in the Physical Properties data table, answering yes or no for each substance. 5. Clean up your lab station and return all equipment to its proper place. 6. Dispose of substances in the containers designated by your teacher. 7. Wash your hands thoroughly before leaving the lab. 9

12 Student Derived Separation of a Mixture Lab Procedure ***Be efficient- the fewer steps, the better!*** Teacher Approval: 10

13 Name Date Period Data Table: Physical Properties Magnetic? Soluble in Water? Filters out? Sand Salt (NaCl) Iron Filings Conclusions 1. Briefly describe the method you used to separate each substance from the mixture. For each substance, explain which physical property enabled you to use this method. Physical Property Method Sand Salt (NaCl) Iron filings 2. Analyze the success of your procedure. On a scale of 1 to 10, with 10 being the best and 1 being the worst, how successful were you in separating and recovering each of the four components? Sand 1-10? Explanation Salt (NaCl) Iron filings 3. What improvements to your procedure could be made to achieve better results or to make the process more efficient (i.e. faster and/or easier)? Consider changes in the following: techniques, sequence, equipment, etc. EXPLAIN: 11

14 Density Lab Introduction: Density is the ratio of an object's mass to its volume. D = m / v. Gold has a density of 19.3 g/cm 3, the average rock has a density of 3 g/cm 3, and water has a density of 1 g/ml. 1 g/ml means that 1 ml (or cm 3 ) of water has a mass of 1 gram or 1 liter of water has a mass of 1 kg. You will be finding the density of several solids. The masses will be found on a balance. The volumes will be calculated from measurements or determined by water displacement. When making all measurements, read the interval and estimate one more digit beyond the interval. Water displacement: Pre-lab Questions: 1. Which is less dense, a marshmallow or hot chocolate? Choose the best answer. a) It depends on how much you have c) The hot chocolate, because it is a liquid b) The marshmallow, because it floats d) The marshmallow because it weighs 1.0 g and the chocolate powder 5.0 g 2. Which is more dense, water or oil? Why? 3. What mass does 3.0 cm 3 of gold have? Hint: read the Intro! Procedure: Cylinders 1. Mass one of your cylinders. Record in data table. 2. Fill a graduated cylinder of appropriate size about half full, and record the exact amount in the data table. Don t forget to read the bottom of the meniscus at eye level! 3. Gently place the metal cylinder into the graduated cylinder and record the new volume in the data table. 4. Calculate the volume and density of the cylinder (D=m/v), and determine the identity of the metal. 5. Repeat steps 1-4 for your other cylinder. Procedure: Cubes 1. Mass one of your cubes. Record in data table. 2. Measure height, width, length of cube. Record in the data table. 3. Using the formula for the volume of a cube (L x W x H), calculate and record the volume in the data table. 4. Calculate the density of the cube (D=m/v), and determine the identity of the metal. 5. Repeat steps 1-4 for your other cube. Data Table: Cylinders Measurement Brown/gold cylinder value with unit Silver cylinder value with unit Mass of cylinder Initial volume of water Final volume of water Volume of cylinder (final initial) Density of cylinder (experimental value) Identity of metal (see table on back) Data Table: Cubes Measurement Brown/gold cube value with unit Silver cube value with unit Mass of cube Length of cube Width of cube Height of cube Volume of cube (L x W x H) Density of cube (experimental value) Identity of metal (see table on back) 12

15 Name Date Period Post-Lab Questions: Density Lab 1. In this lab, you used both the water displacement method (cylinder) and a direct measurement method (cube) to determine volume. If you wanted to determine the volume of a rock for a density experiment, which method would you choose? Why? 2. Calculate the % error for your density determinations for each cylinder. Fill in the table and show your work! Brown/Gold cylinder Your experimental value for density = (from your data table on other side) The accepted value for the density = (see table at bottom) Percent Error for your density = accepted value experimental value x 100 = accepted value Silver cylinder Your experimental value for density = (from your data table on other side) The accepted value for the density = (see table at bottom) Percent Error for your density = accepted value experimental value x 100 = accepted value 3. Discuss why there is error in your lab. (Why weren t the experimental values the same as the accepted values?) 4. Using the accepted values (see table below) for the densities of the two metals in the cylinders, calculate the mass of 100. cm 3 of each metal. Remember: D = m. Solve for mass (m). Show work! v Mass of brown/gold cylinder = Mass of silver cylinder = 5. At least 2 of your samples were made out of the same metal. However, they did not contain the same amount of matter (cube vs. cylinder). Compare the densities of these two samples. They are most likely not exactly the same. Should they have been the same? Explain. HINT: is density an extensive or intensive property? Accepted values for metal densities: Metal Density (g/cm 3 or g/ml) Aluminum 2.70 Zinc 7.13 Iron 7.87 Brass (mixture of copper and zinc) 8.00 Copper 8.94 Lead

16 Crime Scene Chemical Investigators When a crime is committed, it is responsibility of the police or other law enforcement agencies to collect evidence in order to solve the crime. Although scientists and police often use hunches or their gut feelings about a situation, it is only the factual information that will uphold in court. Because of this, the evidence is carefully collected and processed by trained professionals. In this experiment, you will serve as a laboratory technician that is processing data from two different crime scenes. Your goal is to determine the identity of the unknown substances based on their physical and chemical properties. In order to identify substances found at a crime scene, both physical and chemical properties of a substance are used. Physical properties are those characteristics that can be observed without changing the substance s identity such as color, odor, melting point, boiling point, and density. Chemical properties describe how a substance interacts with other chemicals. The FBI Crime Lab works very closely with pharmaceutical companies such as Glaxo-Smith Kline and Bayer. Together they produce tests for all new drugs to identify small samples of a drug. These tests are then stored in files for use by forensics investigators. Background Information for the Crime Scene When the police arrive on the site of an overdose, many drugs exist as a white powder, and it is important that they be properly identified. Some over-the-counter drugs may cause poison or lead to the death in the case of an overdose, especially if the victim is a child. Here are some facts about two of the most commonly used over-the-counter drugs. Aspirin, or acetyl salicylic acid, is a commonly used to treat pain. It can easily be identified by treating it with a solution of iron (III) nitrate, Fe(NO 3) 3. In the presence of this solution, aspirin turns a brownish purple color. Since a solution of aspirin is also acidic, it will turn red in the presence of the Universal Indicator. As with most medicines, aspirin also contains fillers, such as starch, silicon dioxide, and preservatives. Tylenol TM contains acetaminophen as its active ingredient or pain killer. Because Tylenol TM is not acidic, it will not turn red in the presence of the Universal Indicator. Other white solids are also often present at crime scenes and in some cases mixed with illegal drugs. It is important for forensics scientists to be able to determine if the substances found are just these fillers or if some quantity of an illegal drug is present. Baking soda, sodium hydrogen carbonate, is used in the making of crack cocaine. It can be detected by adding an acid, such as vinegar, to a solution of baking soda. In the presence of an acid, baking soda will fizz or bubble. A solution of baking soda is also basic; therefore, it will turn blue in the presence of the Universal Indicator. Flour is a common household substance and is a carbohydrate with a high molecular weight because it is composed of numerous glucose units. By adding iodine to flour, it will indicate the presence of a starch by turning brown or black. Sucrose is a common table sugar and is made of a unit of glucose and a unit of fructose. Typically, sugar has a texture that is difference from the other potential substances. Therefore, its physical appearance is commonly used to distinguish it from other substances. 14

17 Procedure 1. At your lab table, there are 5 labeled pipettes containing: water, universal indicator, vinegar, Fe(NO 3) 3, and iodine. If the pipettes are low, fill them using the solutions in the beakers at the front of the room. When filling, make sure that NO cross-contamination occurs. 2. Record the physical properties of each of the substances we will be testing in the data table. (Aspirin, Tylenol, Baking Soda, Flour, and Sugar) 3. Add a small sample of aspirin to a well on the well plate. (see diagram on lab table) Add 10 drops of water to the sample. Record your observations in the data table- Does the solid dissolve? Or does it not dissolve? 4. Add 1 drop of Universal Indicator to the same well. Record your observations. 5. Repeat the previous step for each of the known chemicals. Be sure that each chemical is added to a separate well. (see diagram on lab table) No chemicals should be mixed. 6. Add a new sample of aspirin to the well below. (see diagram on lab table) Add 10 drops of vinegar to the second well. If a gas is formed, a chemical reaction is occurring. You should record FIZZ in the appropriate place on the data table. 7. Repeat the previous step for each of the known chemicals. (see diagram on lab table) Be sure that each chemical is added to a separate well. No chemicals should be mixed. 8. Add another new sample of aspirin to the well below. (see diagram on lab table) Add 5 drops of Fe(NO 3) 3 to the sample. If you see a brownish-purple color form, record a P in your data table when you see the reaction. 9. Repeat the previous step for each of the known chemicals. (see diagram on lab table) Be sure that each chemical is added to a separate well. No chemicals should be mixed. 10. Add a final new sample of aspirin to the well below. (see diagram on lab table) Add 5 drops of iodine to the substance. If starch is present, it will turn black. When you see this reaction occur, write B in your data table. 11. Repeat the previous step for each of the known chemicals. (see diagram on lab table) Be sure that each chemical is added to a separate well. No chemicals should be mixed. 12. Clean the well plate by inverting it on a paper towel. Next, rinse the well plate with water in the sink and dry it with a paper towel. 13. Obtain a sample of each of the two unknowns. The unknown samples were found at the second crime scene. Analyze each sample just as you analyzed the known samples to determine which of the known chemicals are present. Keep in mind that the unknown samples could be a mixture of one or more of the known chemicals. Record all observations in your data table. Clean-Up Clean-up your lab station by rinsing your well plate in the sink with water and drying it with a paper towel. Place the pipettes and all other materials back in an orderly manner, so the lab station looks as it did when you arrived. 15

18 Name Date Period Chem Teacher Analysis of a Crime Scene Pre-lab Questions 1. After reading the background information about the crime scene, explain how you will test for the presence of each of the chemical below. Be sure to include the expected outcome of the test. Chemical Description of Test Expected Outcome Aspirin Tylenol Baking Soda Flour Sugar 2. When iron(iii) nitrate or the Universal Indicator is added, what type of properties are you observing: chemical or physical? How can you tell? Is the chemical identity of the substance being changed? 16

19 Data Physical Properties Aspirin Tylenol Baking Soda Flour Sugar Unknown # 1 Unknown #2 Water Universal Indicator Vinegar Fe(NO3)3 Iodine Post-Lab Questions 1. What is indicated when a substance turns red with the Universal Indicator? What does it indicate if it turns blue? Red: Blue: 2. What was the point of testing the known substances? 3. What does the first unknown sample contain? Support your conclusion with facts from your experiment. 4. What does the second unknown sample contain? Support your conclusion with facts from your experiment. 17

20 An Investigation Into Atomic Structure Purpose Describe the composition of the atoms represented by the items in the Ziploc bags. The atoms are contained in 10 Ziploc bags and the subatomic particles are coded as follows: - protons are WHITE BEANS - electrons are POPCORN KERNNELS - neutrons are RED BEANS You will also need to use the following information: atomic # = # of protons in an atom (A=P=E) mass # = # of protons + # of neutrons (M-A=N) Procedure Analyze each atom (count the number of beans or kernels for each type) and record the information in the data table below. ***DO NOT OPEN THE BAGS!!!*** Data Table BAG # of protons # of electrons # of neutrons Atomic # Mass # Element Name w/ mass # (isotope notation) example Lithium - 7 A B C D E F G H I J 18

21 Name Date Period Questions 1. Refer to a periodic table. ONLY for Elements A J from your data table, label the correct box on the periodic table below with the element symbol and atomic number. 2. What pattern can you observe in the protons as you go across a period () on the table? Circle: increase, decrease, stay the same 3. Based on your answer to the previous question, how is the periodic table arranged? 4. If you were given the atomic number and mass number for an isotope of an element, how would you find the number of neutrons? 5. Refer to your answer to #4 above. If you had an element with an atomic number of 35 and a mass number of 80, how many protons, neutrons, and electrons does it have? Protons Neutrons Electrons 6. What element is question #5 referring to? 7. What do we know about the overall charge of the atom if it has the same number of protons and electrons, as each of these did? 19