02/19/14 Classifying Chemical Reactions Introduction Pre-lab questions 1. Which reactants used in this experiment are flammable? Discuss the safety precautions that are necessary when working with flammable materials in the lab? 2. Summarize the following description of a chemical reaction in the form of a balanced chemical equation? 3. Common observations of a chemical reaction are described in the introduction section. For each observation, name a common or everyday occurrence that must involve a chemical reaction? Research question What is the appearance of reactant, Evidence of chemical reaction, and properties of a product? Background information The experiment is to observe a variety of chemical reactions and to identify patterns in …show more content…
2. When the magnesium ignited, removed it from the flame and held it over an evaporating dish or a pyrex watch glass until the metal had burned completely. Let the product fall into the evaporating dish. 3. Turned off the laboratory burner and observed the properties of the product in the evaporating dish. 4. Recorded observation in the data table Reaction 2 - 1.Used a Beral- type pipet, added about 2mL (40 Drops) of 1M hydrochloric acid solution to a small test tube. 2. Obtained a 2-3 cm strip of magnesium metal ribbon and coiled it loosely into a small ball. Added the magnesium metal to the acid in the test tube. 3. Carefully felt the sides of the test tube and observed the resulted chemical reaction for about 30 seconds. 4. While the reaction was still occurred, lighted a wood splint and quickly placed the burned splint in the mouth of the test tube. Do not put the burned splint into the acid solution. 5. Recorded observations in the data table. Reaction 3- 1. Obtained a clean and dry test tube and placed a small amount ( about the size of a jelly bean) of ammonium carbonate into the test tube. 2. Used a test tube clamp to held the test tube and gently heated the tube in a laboratory burner flame for about 30 seconds. 3. Removed the test tube from the flame and places a piece of moistened litmus paper in the mouth of the test tube. Identified any odor that is readily apparent by wafted the fumes toward your nose. Caution: Do not sniff
And finally into test tube 3, I pipetted 1.0 ml turnip extract and 4.0 ml of water. The contents of test tube 1 was poured into a spectrometer tube and labeled it “B” for blank. “B” tube was now inserted it into the spectrometer. An adjustment to the control knob was made to zero the absorbance reading on the spectrometer since one cannot continue the experiment if the spectrometer is not zeroed. A combination of two people and a stop watch was now needed to not only record the time of the reaction, but to mix the reagents in a precise and accurate manner. As my partner recorded the time, I quickly poured tube 3 into tube 2. I then poured tube 2 into the experiment spectrometer tube labeled “E” and inserted it into the spectrometer. A partner then recorded the absorbance reading for every 20 seconds for a total of 120 seconds. After the experiment, a brown color in the tube should be observed to indicate the reaction was carried out. Using sterile techniques, any excess liquid left was disposed
The content of this section depends to a large extend on the nature of the experiment. Topics here should include a section labelled:
Procedure: In this experiment, various chemicals were mixed together, to determine a reaction. Using two drops from chemical 1 and two drops of chemical two, unless otherwise stated, then recording the type of physical reaction or color changes that occurred.
These reactions can be seen from just a little bit of reaction all the way up to a complete change of the entire sample tested. Some samples of those tested in this experiment which showed the chemical reaction were the baking soda/ammonia mixture, the Epson salt and baking soda mixture as well as the food coloring mixed with the baking soda and bleach. 2. Which reactions, if any, do you believe showed no evidence of chemical change? Justify your reasoning.
A chemical reaction is when substances (reactants) change into other substances (products). The five general types of chemical reactions are synthesis (also known as direct combination), decomposition, single replacement (also known as single displacement), double replacement (also known as double displacement), and combustion. In this lab, the five general types of chemical reactions were conducted and observations were taken before, during, and after the reaction. Then the reactants and observations were used to determine the products to form a balanced chemical equation. The purpose of this lab was to learn and answer the question: How can observations be used to determine the identity of substances produced in a chemical reaction?
In this experiment you will observe some physical and some chemical changes. You will observe that energy must be used to start some chemical reactions, and that it is produced in others.
C1.Work under the hood! Place a piece of zinc in a test tube. Add about 5 mL of 6 M HCl and allow the zinc to effervesce. Ignite a wooden splint in a Bunsen burner flame and hold this flame to the mouth of the test tube. If hydrogen is generated as one of the
Purpose: The purpose of this experiment is to observe a variety of chemical reactions and to identify patterns in the conversion of reactants into products.
Many signs show that a chemical reaction has occurred. Some ways we know there is a chemical reaction are the formation of gas, formation of precipitate, change in temperature, and,or change in color. In part one of the experiment, we know there was a chemical change because of the formation of the white precipitate. We poured the ammonia and water in the flask with alum and water, forming a white, cloudy substance in between the two liquids. The white, cloudy substance between the two is liquids is also known as aluminum hydroxide. The second part of the experiment was very similar to the first, but in the second part we mixed epon salt, water, and ammonia. The precipitate formed from mixing the epson salt, water, and ammonia was called magnesium hydroxide.
The purpose of this experiment is to distinguish the relationships between reactants and products, in addition to expanding on concepts such as single displacement reactions, mole ratio values, moles to mass, theoretical yields, limiting reactants, excess, stoichiometric relationships and percentage errors.
4.Measure 35mL of warm water and add them into each of the 4 test tubes at about roughly the same time. It is essential that the water is warm. Do not seal the test tube.
Safety glasses: Wear safety glasses to protect eyes from substances, acids and flames that can irritate or damage the eyes.
Describe what you did in the experiment, and include methods and materials used. Do not
A “Chemical Reaction” is where substances interact, producing a chemical change and altering their original molecular or ionic structure to a new one having a different chemical identity.
Half of each tube’s contents are poured into a new test tube each respectively after the tubes are incubated for 1 hour. One set of tubes is tested for: