Chem LabEssay Preview: Chem LabReport this essayEPHS – NicholasChemistry Period 4February 16, 2006Introduction:The purpose of this lab is to identify and record data that shows how heat is involved in chemical change. Also, to explain why a substance can be either a reactant, or a product in a chemical change. Finally, to learn why it is necessary for recycling.
Method:In the laboratory, students were to complete a number of chemical reactions by adding certain chemicals to Copper (II) Nitrate, ultimately turning it back into copper.
Materials:Pyrex test tube 13 ÐŽÐ 100 mm100 ml beakerBurner and tubingRulerLab markerStirring rodIron ringRing standWire gauze, ceramic centeredTest tube rack1.0 M copper(II) nitrate1.5 M hydrochloric acid1.5 M sodium hydroxide12 cm piece of aluminum wireSafety Note:Sodium hydroxide is a caustic and corrosive substance. Be certain to wear safety goggles, apron, and gloves. Avoid contact with skin and eyes. Avoid breathing vapors. If any of this solution should spill on you, immediately flush the area with water and notify your teacher.
Procedure:(Record your observations in the Data Table)In the 100 ml beaker, make a water bath by heating until boiling approximately 50 ml of water. This will be used in Step 5While the water bath is heating make three marks that are 1 cm apart on a 13 ÐŽÐ 100 mm test tube. Make the marks from the bottom up.Add 1.0 M copper(II) nitrate to the first mark on the test tubeAdd 1.5 M sodium hydroxide to the second mark on the test tube. Mix with the stirring rod. Rinse the stirring rod. Touch the bottom of the outside of the test tube to see if heat has been released. The copper containing product is copper (II) hydroxide. The other product is sodium nitrate.
Put the test tube in the water bath begun in Step 1. Heat it until no more change occurs. The products are copper (II) oxide and water.Remove the test tube from the hot water bath. Turn off the burner. Cool the test tube and its contents for 2 minutes in room temperature water. Add 1.5 M hydrochloric acid to the third mark. Mix with the stirring rod. Rinse the stirring rod. The products are copper (II) chloride and water.
Place a 12 cm piece of aluminum wire in the test tube. Leave it until no more reaction is observed. Touch the bottom of the test tube to check for temperature change. Two reactions take place. Copper (II) chloride and aluminum produce copper and aluminum chloride. The aluminum also reacts with the hydrochloric acid to form hydrogen and aluminum chloride.
Remove the wire from the test tube. Compare the copper formed to a sample of copper wire.Dispose of the solids and the liquids formed in the experiment as your teacher directs. Empty the water from the hot water bath. Clean all equipment used. Remember to wash your hands before you leave the laboratory.
Results:Data Table 1Reactants Products Observations of ProductsPrecipitate (Solid) Supernate(Liquid)Copper(II) nitrate(blue solution)Sodium hydroxide(colorless solution)Copper(II) hydroxideWaterNone Visible Opaque, vivid aqua coloration/Very thick, almost gel like. Mixture cooled a bitCopper(II)hydroxide(heat)Copper(II) oxideWaterBrownish-Black substance forming at bottom of test tube Transparent, clear, quite pure lookingCopper(II) oxideHydrochloric acidCopper(II) chlorideWaterLiquid is semi- opaque. Brownish ÐC Black in color. Lustrous material settling at bottom of test tube. Heat of mixture rose a small bit.AluminumCopper(II) chlorideCopperAluminumChlorideLustrous Material at bottom Transparent, blue-tinged liquid bubbles beginning to rise.Aluminum
A new material forming. Capped and glazed, this is similar to the first product – it gives the illusion of water but is still more vivid, but not clear. Aluminum
This could very well be another “liquid” in the mix and this one can be made quite opaque with a glass of water or not, but this is not the real thing. There are two ways to make something translucent in one experiment. I did this experiment with my son from a while ago (when the thermometer was actually on for 2 hours), so I’ll explain how to set a thermometer on it here.A new thing I think you might notice is the coloration. Red is less clear and white less visible; that seems to suggest the “water” of some of the products has the water of the “silk particles” being mixed. If that’s a problem, add hydrogen on the final coat to make this new (I like to think of it as hydrogen) hydrological material, with aluminum above, or at the bottom as a hydrate, and a bit of polyethylene (like polypropylene, which makes it more translucent). In these two cases, these products are much more different – it would seem like the water of the “silky particles” is mostly water. At the bottom, if any of these products have the same color it would probably be a little yellowish, and I believe that could be the result of the hydration – maybe it is this tint in white, that is why we can see the hydrogen crystals in our eyes, and that could be a hint to the liquid? If you’re not really sure – do this if there is some hint at the water, and then see what it looks like from that. If this is not the correct color, try adding 1/2 cup of water to that. Then let it steep for up to two hours – this could be like baking soda, and the result looks better. The problem with this liquid is that when the water of the “silker” “water” has just gone down the liquid becomes “yellowish” because it appears yellowish just slightly. This is one of those issues that is so common that there are the “other options” (cotton and the like) that are “non-toxic” but are actually dangerous. If you want to make a glass jar/trainer (like this one to keep your water from getting too high) – don’t want the water to become dirty. The glass jar can make a pretty good indicator (that it is OK to add water, when it is cool) of how well this is mixing the same liquid. Here’s one I made with one gallon of water to give an idea