66666666666666666666666666666666666666666666666666666666666666666666 Synthesis In this experiment you will perform four classes of chemical reactions: • synthesis — a reaction combines two or more substances to create a new one. For example, iron rusting is a synthesis reaction. • decomposition — a reaction in which a substance breaks apart into simpler constituents. • single displacement — a reaction in which one substance in a molecule is replaced by another. • double displacement — a reaction two molecules swap atoms to form new substances. After performing these reactions, you will identify the products that result and write a balanced chemical equation to represent each of those reactions. Balanced Chemical Equations Every chemical equation represents a specific chemical reaction. Equations identify the reactants (the substances that interact together) and the products (new substances that are formed as a result of that interaction). Reactants appear on the left side of an equation, and the products appear on the right. They are separated by an arrow (?),which indicates reaction has taken place and the direction of the reaction. ? For an equation to be correct, it must be balanced: the same number of each kind of atom must appear on both sides of the equation. For example, when iron rusts, it combines with oxygen to form a new compound, iron oxide (Fe2O3). The balanced chemical equation for this reaction is: ? ? ? ? 4Fe(s) + 3O2(g) ? 2Fe2O3(s) This equation indicates that four iron atoms combine with three molecules of diatomic oxygen (for a total of six oxygen atoms) to produce the two molecules of iron oxide, each with two atoms of iron and three atoms of oxygen. Signs are used to indicate what state the molecules are in: • (s) — solid • (l) — liquid • (g) — gas • (aq) — aqueous in water (compound dissolved in water) Procedures Experiment 1: Synthesis 1. Take a balance from the Instruments shelf and place it on the workbench. 2. Take a crucible from the Containers shelf and place it on the balance. Record the mass of the crucible. 3. Remove the crucible from the balance. Add 5g of magnesium (Mg) to the crucible from the Materials shelf. 4. Place the crucible on the balance. Record the total mass of the crucible plus magnesium (Mg). Remove the crucible from the balance. 5. Take a Bunsen burner from the Instruments shelf and place it on the workbench. 6. Drag the crucible and place it on the Bunsen burner. Turn on the Bunsen burner by clicking the black knob at the bottom to the low flame. (Clicking on the knob multiple times will increase the intensity of the flame until it is clicked off.) 7. Wait 1 – 2 minutes and then remove the crucible from the flame by placing it on the workbench. 8. Wait 1 – 2 minutes for the crucible to cool, then place it on the balance. Measure and record the mass of the crucible and its contents. (Remember to press Save Notes.) 9. Remove the crucible from the workbench by dragging it to the Recycle Bin. Experiment 2: Decomposition 1. Take a new clean crucible from the Containers shelf and place it on the workbench. 2. Add 5g of copper(II) carbonate hydroxide hydrate (Cu2CO3(OH)2*H2O) from the Materials shelf to the crucible. 3. Place the crucible on the balance. Record the total mass of the crucible and its contents in your Lab Notes. 4. Remove the crucible from the balance and place it on the Bunsen burner. ? 5. Double-click the crucible to open its Item Properties. Check the option to "Show Contents" and click OK to give you a cut-away view of the crucible's contents. ? 6. Turn on the Bunsen burner to the low flame. 7. Watch the crucible until the green compound changes color. 8. Remove the crucible from the Bunsen burner. ? 9. Drag the crucible and place it on the balance. Record the mass of the crucible and its contents in your lab notes. ? 10. Clear the workbench by dragging all of the Instruments and Containers to the Recycle Bin. Experiment 3: Single Displacement 1. Take a clean 150 mL Erlenmeyer flask from the Containers shelf and place it on the workbench. 2. Add 15 mL of 6M hydrochloric acid (HCl) from the Materials shelf to the Erlenmeyer flask. 3. Double click on the Erlenmeyer flask and select the "Close" to put an airtight stopper on it. 4. Take a thermometer from the Instruments shelf and connect it to the Erlenmeyer flask. 5. Take a pressure gauge and connect it to the Erlenmeyer flask. 6. Add 0.25 g of Zinc (Zn) from the Materials shelf to the Erlenmeyer flask. You can try the same experiment with 25 g of zinc and see what happens. (Even though your flask is closed, stopper is automatically lifted and then replaced quickly. The material is added as if by a syringe poked through the stopper.) 7. Observe and record any indication that a reaction has occurred in your lab notes. (Don't forget to save your notes.) 8. Wait for the solution in the Erlenmeyer flask to cool down within half a degree of room temperature (21.5?C). Remove the thermometer and pressure gauge. 9. Take a syringe from the Containers shelf and connect it to the Erlenmeyer flask. This allows gas to escape from the Erlenmeyer flask into the syringe. 10. Roll your mouse cursor over the syringe (without clicking the mouse). Record the volume of the gas collected in the syringe in your lab notes by reading the yellow tag that pops up. 11. Clear the workbench by dragging all of the Containers and Instruments to the Recycle Bin. Experiment 4: Double Displacement 1. Take two 50 mL beakers from the Containers shelf and place them on the workbench. 2. Add 15 mL of 1M sodium hydroxide (NaOH) solution to one of the beakers. 3. Add 6 mL of nickel chloride solution (NiCl2) to the other, empty, beaker. (You may want to label your beakers by double-clicking on each to get the Item Properties window.) 4. Observe the contents of each beaker. 5. Pour the entire contents of one beaker into the other. Record your observations of the reaction that occurs in your Lab Notes. (Remember to save your notes.) Experiment 1: Synthesis Mass of crucible = 88.00 g Mass of crucible + magnesium = 93.000 g Mass of crucible + magnesium after heated = 96.289 g Experiment 2: Decomposition Mass of crucible +copper (II) carbonate hydroxide hydrate =93.000g Mass of crucible +copper (II) carbonate hydroxide hydrate after heated =91.327g Experiment 3: Single Displacement 15ml of HCL + 0.25g of Zinc pressure gauge indicate 1.71 atm and it boiled but when I add 100 more zinc from the first the flask is explode 92.2 ml of volume Experiment 4: Double Displacement it turn into little cloudy Introductory Information: Heading, title, purpose, materials and procedures (20 points) Data, Calculations and Results (25 points) Conclusions and Critical Thinking (25 points) Organization (20 points) Use of Accurate Scientific Terminology and References (10 points)