How many moles of zinc are in a penny? Purpose: This lab is being performed so students can visualize a single-replacement reaction and calculate how much zinc is in a post-1982 penny. Materials: A post- 1982 penny steel wool 3 M HCl graduated cylinder small beaker tongs balance paper towels sharp edge Safety: 3 M hydrochloric acid (HCl) is fairly caustic. Wash hands immediately if you spill on them. Wear goggles.
Add the HCl SLOWLY to the magnesium by running it down the side of the beaker. Adding the acid too quickly will result in the spattering of the acid. Write down any observations of the reaction. 6. After all the acid has been completely added and the reaction has stopped, use a pipette to add a few extra drops of acid into the beaker until the reaction stops.
12. Place a paper towel over the drain, pour the content of the well plate, throw the paper towel and rinse the well plate. DATA, OBSERVATIONS, AND CALCULATIONS: Data Table: Oxidation - Reduction | | Reactions | Mg in Na2SO4 | Bubbles | Zn in MgSO4 | Small bubbles | Pb in Zn(NO3)2 | Dark lead changed into lighter color | Pb in FeCl3 | Changed the lead into slight green yellow | Fe in CuSO4 | Changed the iron into orange color | Note: I added more than 10 drops to make sure that the pieces are well covered. QUESTIONS: A. Based on your observations make an activity series of the metals used.
Gently stir the resulting mixture for 30-60 seconds. * Step 4 –Place a suitable filter (cloth, filter paper or a fine sieve) over an empty glass, and secure it with the rubber band. Pour the mixture into the filter. If the mixture is too thick, stir in more of the extraction solution. Leave to filter for about 10 minutes.
The pre-1983 penny was made of an alloy of copper and zinc. An alloy is “a substance that has metal characteristics and consists of two or more different elements”. (Coordinated Science, pg.1005) Our objective is to find the metal used inside a post-1983 penny. The accepted value of the density of a post-1983 penny is 7.05g/cm3. “Density is the mass per unit volume of a material”.
Introduction: Thyme contains a surprising amount of iron compounds. This experiment enables us to determine the amount of iron(II) present in dried thyme by means of a redox reaction. Method: 1. Weigh accurately about 1g of dried thyme and put into a 250cm3 beaker. Record the mass of thyme used.
12. Repeat steps four through ten two more times. Variables: Controlled – * Water Temperature * Drop size * Height of drop * Side of penny * Person who drops water on the pipette * That the penny is dry * Amount of mixture for each solution Independent – * Aqueous solution * Penny Dependent – * Number of drops for each solution Data Collection & Processing: Number of drops of an aqueous solution on a penny Substances | Test 1 | Test 2 | Test 3 | Test 4 | Test 5 | Average | Class Averages | Tap water | 46 | 43 | 46 | 35 | 43 | 43 (42.6) | 34 (33.5) | Salt water | 46 | 30 (Phil shook table) | 39 | 21 | 25 | 32 (32.2) | 27 (27.18) | Soapy water | 17 | 31 | 25 | 19 | 23 | 23 | 16 (16.45) | Conclusion & Evaluation: The hypothesis is supported by the data recorded. The hypothesis states that if water is polar and cohesive then the purer the water the more drops that will collect on the penny. If the student averages are compared for tap water, salt water, and soapy water then tap water
As the water is being evaporated, record the temperature every 2 minutes. 6. Weigh beaker with dry salt residue left in it. Record the weight in grams. 7.
Gravimetric Determination of Sulfate Purpose The purpose of this lab is to determine the percentage of sulfate in the hydrate by precipitating the sulfate as barium sulfate. Materials Filler paper Sodium sulfate Graduated cylinder Bunsen burner Watch glass Beakers (250 mL, 400 mL) Rubber bulb Graduated pipette Beaker tongs Funnel Filter Paper Sodium Sulfate Drying oven Wash bottle Stirring rod Silver nitrate Hydrochloric acid Distilled water Small test tube Procedures First, .4861 grams of sodium sulfate was placed into a clean 400mL beaker. Exactly 200mL of water and 1mL of HCl was added to the same beaker. A watch glass was placed on the beaker and the solution was heated using the Bunsen burner to a gentle boil. The watch glass was removed with the beaker tongs.
b) When pouring agar into the petri dish, pour just enough to fill the dish about half way. c) Although you must work fairly quickly, pour the agar gently to minimize the number of bubbles (bubbles look amazingly similar to colonies when the agar hardens). 4. When you are ready to pour: a) Pull out the container of DMA and remove the cap. b) Open the cover of the petri dish halfway and pour in the agar to just cover the bottom of the dish.