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Predicting Products Lab
Introduction: Thought this unit you have learned about how to predict the products of reactions simply by looking at the number of reactants and types. You know that a synthesis reaction consists of two similar reactants becoming one, and that a decomposition reaction consists of one reactant becoming two or more similar products. Furthermore you have learned that a single replacement reaction usually features a single reactive metal replacing a less reactive metal, and double replacement reaction consists of two polyatomic substances exchanging cations or anions. In this lab you will receive a series of reactants. Using only the reactants you will predict the products of the reaction and then determine the accuracy of your predicting through experimentation. For instance if you feel that oxygen gas will be a product of a reaction you will insert a glowing splint into a test tube of collected gas and see if it reignites. If it does then you where correct. If it does not then your prediction of the products was incorrect and you need to re-test for another product. The following are the checks for gas production that you will be able to perform in this lab:
Oxygen (O2) – insert a GLOWING (not flaming) splint into a test tube full of the collected gas. If it reignites then oxygen was produced
Hydrogen (H2) – Insert a flaming splint into a test tube full of collected gas. If you hear a pop then hydrogen gas was produced
Water vapor (H2O) – if water vapor was produced then cobalt chloride paper will change color when passed over the top of the test tube
Ammonia (NH3) – if ammonia gas is produced then you will be able to smell it when you waft the fumes of the test tube towards your nose
Carbon dioxide (CO2) –If a flaming splint extinguishes when inserted into a test tube of the collected gas then carbon dioxide was produced by the reaction
Before You Begin:
- What will you be doing in this lab?
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- What is the goal of this lab?
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- If you predict that hydrogen, oxygen, ammonia, carbon dioxide, and water vapor are produced by a reaction how will you know that you where correct or incorrect?
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Procedure:
Read the procedure for each reaction in its entirety before doing it so that you have the necessary materials to complete the procedure.
Reaction 1:Cut a 3 cm piece of magnesium ribbon. Clamp the magnesium with a pair of crucible tongs. Ignite the magnesium in a Bunsen burner flame and collect the ashes on a watch glass.
Mg + O2 →
What type of reaction do you think this is? ______
Reaction 2:Obtain a piece of magnesium. Add 10 mL of hydrochloric acid to a test tube and place the test tube in a rack. Add the magnesium to the acid. Clamp a second test tube and hold it, inverted, over the mouth of the reaction test tube to collect the gas being produced.
Mg+ HCl →
What type of reaction do you think this is? ______
What tests will you perform to see if your prediction of the products are correct? ______
Reaction 3:Obtain one scoop of ammonium carbonate and place it into a test tube. Clamp the test tube and heat it in a Bunsen burner.
(NH4)2CO3 →
What type of reaction do you think this is? ______
What tests will you perform to see if your prediction of the products are correct? ______
Reaction 4:Add 5 drops of Iron Nitrateand 5 drops of Potassium thiocyanate to a watch glass.
KSCN + Fe(NO3)2 →
What type of reaction do you think this is? ______
Reaction 5:Add a small amount of ethanol into anErlenmeyer flask. Light a splint on fire and place it in the Erlenmeyer flask. Once the fire has dies down begin your tests
C2H6O + O2→
What type of reaction do you think this is? ______
What tests will you perform to see if your prediction of the products are correct? ______
Reaction Number / Reactants / Observations / Cobalt chloride paper / FlamingSplint / Glowing splint / Ammonia Oder1 / Mg + O2
2 / Mg + HCl
3 / (NH4)2CO3
4 / Fe(NO3)2 + KSCN
5 / C2H6O + O2
Questions:
1. Write complete, balanced equations for each of the following:
a. When KBrO3is heated, it decomposes into KBr and a gas that reignites a glowing splint.
b. Sodium metal reacts violently with water to produce NaOH and a gas that pops in the presence of a flame.
c. When Ca(OH)2 is heated, it makes CaO and a substance that will turn cobalt chloride paper pink.
d. When CH4 is burned in the presence of O2 it produces a substance that will extinguish a flaming splint and a substance that turns cobalt chloride paper pink.
2. Identify the reaction type for each reaction in question 2.
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Abstract:
Begin with 1 to 3 sentences that introduce the concept of the experiment (Predicting the products of chemical reactions from the reactants).
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Next write 1 or 2 sentences describing what you did in the experiment:
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Next write 1 or 2 sentences describing how you determined what the products of the reaction were:
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Finally list the results of the experiments:
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Now put all of the above together into one coherent and concise paragraph.
(Note: Don’t use first person and watch your tenses)
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Name: ______Per: _____
Abstract for Predicting products lab:
During the course of any day, a person experiences literally thousands of chemical reactions. Every chemical reaction involves two basic components, reactants or what goes into a chemical reaction, and products, what comes out of a chemical reaction. There are a number of chemical reactions who’s products can be predicted before the reaction even takes place simply buy looking the number and kinds or reactants. For instance the products of a synthesis reaction can be determined by observing that elements are the only reactants going into a reaction. The products of a decomposition reaction can be determined by observing that only one substance is reacting. A single replacement reaction always consists of a metal reacting with an ionic compound, and a double replacement reaction always involves two polyatomic ionic compounds reacting. Lastly, a combustion reaction always involved a hydrocarbon reacting with oxygen gas to produce carbon dioxide and water vapor. In this lab a series of chemical reactions where preformed and their products where predicted and verified through scientific experimentation. If oxygen gas, hydrogen gas, or carbon dioxide was produced by a chemical reaction then those gasses where collected and tested for by reigniting a glowing splint, exploding in the presence of flame, and or extinguishing a lit splint. Furthermore water vapor was judged to be produced if a color change was seen in cobalt chloride paper, and ammonia gas’ production was verified by odor. By testing for the previous gasses and observing the reactants or each of the reactions it was determined that magnesium and oxygen gas react in a synthesis reaction to produce magnesium oxide; Magnesium and hydrochloric acid react in a single replacement reaction to produce magnesium chloride and hydrogen gas; Ammonium carbonate when heated decomposes to form ammonia gas, water vapor and carbon dioxide; Ferric nitrate and potassium thiocyanate react in a double replacement reaction to produce ferric thiocyanate and potassium nitrate; and finally ethanol reacts with oxygen to produce carbon dioxide and water vapor.
What was good about your abstract?
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What about needed improvement?
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What could you have done during the experiment in order to improve your abstract?
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What will you remember the next time you write your abstract?
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Staple your abstract to this paper and correct it in a different color ink using my abstract as a guide. If you don’t have the abstract simply rewrite your abstract on the back.No credit will be given for plagiarism of the above abstract.