Download Chemical Reactions

Chemical Reactions
By: Jasmine Gilbert, Matt Huber and Dr. Faith Yarberry
In this module the students will:
Learn to identify a chemical reaction as a single displacement, double displacement,
synthesis, or decomposition reaction.
Learn to identify precipitation reactions and be able to utilize the solubility rules to
determine the state of matter associated with each species in the reaction.
Learn how to identify acid / base neutralization reactions, including esterfication and
amide formation, and how to identify their products.
Understand Oxidation-Reduction reactions.
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Chemical Reactions Lecture
Lesson 1: Double Displacement, Single Displacement, Synthesis, Decomposition?
Reactions may be described in many ways. One way is to describe the reaction by what
physically occurs during the reaction. Yet another way is to describe the reaction according to
the chemical process it undergoes. Each of these will be discussed separately but overlaps will
be shown where appropriate.
Four terms are used to describe reactions by what physically occurs within the reaction equation.
These four terms are Double Displacement, Single Displacement, Synthesis, and
Decomposition.
Double Displacement reactions, or metathesis reactions, are ones in which the cation swaps
the anion it is attached to. In the picture below the man is the cation and the hat the anion.
Notice that as the reaction proceeds from left to right, the cation simply swapped its anion.
More commonly this reaction is illustrated using the general formula:
AB + CD → AD + CB
Demonstration:
Demonstration Preparation:
Dissolve 1.185 g cobalt (II) chloride hexahydrate, CoCl2 . 6 H2O, in enough water to make 50
mL of solution.
Dissolve 0.200 g sodium hydroxide, NaOH, in enough water to make 50 mL of solution. This
generates heat so add the NaOH slowly to the water.
Demonstration Materials:
0.1 M CoCl2 . 6 H2O
0.1 M NaOH
Test tube
2 droppers
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Procedure:
1. Add 20 drops of cobalt chloride hexahydrate to a test tube. Point out to the class that the
solution is clear though tinted.
2. Add 20 drops of the sodium hydroxide to the test tube. Point out to the class that the
solution is now opaque. Let them know that formation of a solid often indicates that a
chemical reaction occurred.
Observations: Cobalt chloride hexahydrate is a rose colored solution, sodium hydroxide is a
clear solution. When combined they form a teal solution with a solid precipitate. The reaction
is:
CoCl2 (aq) + 2 NaOH (aq) → Co(OH)2 (s) + 2 NaCl (aq)
Precipitation reactions involving two ionic compounds are always double displacement
reactions.
Single Displacement reactions are reactions in which the cation of an ionic compound gains
electrons to become a neutral element while the neutral element in the reaction dissolves to
form a cation. In the diagram below the man in the red shirt represents the neutral element on
the reactant side. As the reaction proceeds the man in the red shirt dissolves taking on the anion.
As this occurs the other male changes from being a cation as a reactant to being neutral as a
product.
More commonly this reaction is illustrated using the general formula:
A + BY → AY + B
Demonstration:
Demonstration Materials:
1.1 M AgNO3
Cu wire
Test tube
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Procedure:
1. Pass around a piece of copper wire. Have the students describe the material.
2. Pass around a solution of silver nitrate. Point out to the students that this solution is a
clear, colorless solution.
3. Place a piece of copper wire into a test tube and cover the wire with aqueous silver
nitrate.
4. Allow this reaction to sit until the end of class.
Observations: The copper is a shiny, reddish-gold solid; the silver nitrate is a clear, colorless
solution. As the reaction proceeds, the solid begins to turn grey which is the silver plating out
onto the solid copper and the solution begins to take on a blue tint indicating that the copper is
dissolving into solution.
Cu (s) + 2 AgNO3 (aq) → Cu(NO3)2 (aq) + 2 Ag (s)
Single displacement reactions are an example of a redox reaction. Additionally, precipitation
reactions involving an element and an ionic solution will always be single displacement
reactions.
If you would like an exciting video to illustrate a single displacement reaction, show the Brainiac
Thermite video. The reaction:
2 Al (s) + Fe2O3 (aq) → Al2O3 (s) + 2 Fe (molten)
Another cool single displacement reaction occurs when magnesium burns in the presences of
carbon dioxide.
(http://www.metacafe.com/watch/894804/uncontrollable_magnesium_reaction_in_dry_ice/)
2 Mg (s) + CO2 (s) → 2 MgO (s) + C (s)
Synthesis reactions are the result of more than one reactant combining to form a single
product. In the diagram below the reactant bird is wasting away. When the bird eats the worm,
hence combines with the worm, you get a fat bird. The product bird is therefore the result of the
skinny bird combining with the worm.
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The most common way to illustrate this type of reaction is via the general reaction:
A + B → AB
Demonstration:
Demonstration Materials:
Magnesium strip
Bunsen burner
Watch glass
Tongs
Procedure.
1. Pass a strip of magnesium around to your students for observation.
2. Warn your students to look at your face rather than the experiment.
3. With tongs grab a piece of magnesium
4. Place the magnesium into the flame of a Bunsen burner until it ignites.
5. Quickly move the magnesium over the watch glass to collect the reaction residue.
6. Pass the residue around to your students for observation.
Observations: The magnesium is a shiny, silver solid that glows bright white when ignited. A
white solid residue is the result of the reaction.
2 Mg (s) + O2 (g) → MgO (s)
Reactions involving pure metals with oxygen are examples of synthesis reactions as well as
redox reactions.
Decomposition reactions occur when one reactant gives off two or more products. In the
diagram below the reactant egg hatches to give two products, the egg shell plus turtle.
The most common way to illustrate this type of reaction is via the general reaction:
AB → A + B
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Demonstration:
Demonstration Materials:
Ammonium carbonate
Test tube
Test tube clamp
Bunsen burner
Lighter
Procedure:
1. Add a small amount of ammonium carbonate to a test tube.
2. Pass the sample around for the students to make observations. (Smell, appearance)
3. Using test tube clamps, hold the test tube over the flame of a Bunsen burner.
4. Allow the solid to completely disappear.
5. Have a student waft a sample of the gases produced toward their nose and have them
report their findings to the class
6. Have a student look at the top of the test tube and tell the class what they see.
Observations: The ammonium carbonate reactant is a white solid. As this material is heated it
decomposes to form three gases. The smell is indicative of ammonia gas being produced. The
condensation at the top of the test tube is the result of water gas being generated and then the gas
being cooled. The last product is difficult to detect and that is carbon dioxide.
(NH4)2CO3 (s) → 2 NH3 (g) + H2O (g) + CO2 (g)
Lab #1 – gives the student an opportunity to identify reactions as occurring by single
displacement, double displacement, synthesis, or decomposition. It also give them the
opportunity to predict the products for the reactions.
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Lesson 2 – Precipitation Reactions
Lessons 2-4 include a second way to describe chemical reactions. This is accomplished by
evaluating the they types of products formed or the oxidation states of the elements involved.
There are three types of reactions that we will discuss: Precipitation reactions, Acid / Base
Neutralization reactions (also described as dehydration reactions), and OxidationReduction reactions.
Precipitation reactions are reactions that produce a solid product. Many precipitation
reactions involve inorganic chemicals. These reactions fall into the categories of double
displacement or single displacement reactions. Examples of this reaction type include:
CoCl2 (aq) + 2 NaOH (aq) → Co(OH)2 (s) + 2 NaCl (aq)
and
Cu (s) + 2 AgNO3 (aq) → Cu(NO3)2 (aq) + 2 Ag (s)
as discussed previously.
Another example is the reaction of lead (II) nitrate with
potassium dichromate.
K2Cr2O7 (aq) + Pb(NO3)2 (aq) → 2 KNO3 (aq) + PbCr2O7 (s)
Again, the observation that leads to the identification of a reaction as a precipitation reaction is
the formation of a solid referred to as a precipitate. How can the identity of the solid product
be predicted in a double displacement reaction? Via the solubility rules which are listed in the
table below. (They are listed in order of importance.)
The compound will be
Soluble (aq)
Soluble (aq)
Soluble (aq)
Soluble (aq)
Insoluble (s)
Insoluble (s)
If it contains
Group 1, NH4+
NO3-, C2H3O2-, ClO4-, HCO3Halides (F-, Cl-, Br-, I-)
SO42O2-, OHAll other anions
Unless combined with
----------------------------+
2+
Ag , Pb , Hg22+
Ag+, Pb2+, Hg22+, Ca2+, Sr2+, Ba2+
Ca2+, Sr2+, Ba2+
----------------
Have your students predict the state of matter of the reactants and of the products in each of the
following reactions and state whether the reaction is a precipitation reaction.
(NH4)2SO4 + FeCl2 → FeSO4 + 2 NH4Cl
AgNO3 + NaCl → AgCl + NaNO3
2 NaOH + Mg(C2H3O2)2 → 2 NaC2H3O2 + Mg(OH)2
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Lesson 3 – Acid / Base Neutralization Reactions
Acid / Base Neutralization Reactions combine acid and base reactants to form water as one
of the products. Example:
HCl (aq) + NaOH (aq) → H2O (l) + NaCl (aq)
To be able to recognize a reaction as that between an acid and a base, it is necessary to be able to
identify acids and bases.
Demonstration:
Demonstration Preparation:
1.1 M Barium hydroxide octahydrate – dissolve 3.15 g barium hydroxide octahydrate in enough
water to make 100 mL of solution
0.1 M Sulfuric acid – slowly add 0.55 mL of concentrated sulfuric acid to 50 mL of water in a
100-mL volumetric flask. Cap and shake. Fill to the mark with water. Cap and shake.
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Demonstration Materials:
0.1 M Barium hydroxide octahydrate
0.1 M sulfuric acid
Buret
250 mL beaker
Phenolphthalein indicator
Electrode
Stirring rod
Procedure:
1. Give the student the formula of barium hydroxide and sulfuric acid and ask them to
predict the product of the reaction.
2. To a 250-mL beaker add 30 mL of 0.1 M sulfuric acid.
3. To the beaker add 50 mL of water and 2 drops of phenolphthalein.
4. Ask the student for their opinion as why the water you just added should not make a
difference in our reaction. (Point out to them that it is the sulfuric acid reacting with
the sodium hydroxide that is important and that the moles of H2SO4 did not change,
only the concentration.)
5. Fill a buret with barium hydroxide.
6. Place the beaker under the buret and drop the buret tip so that it is just below the
mouth of the beaker.
7. Place the electrodes down into the beaker and plug in the system.
8. Ask the students to explain why the light is currently glowing brightly.
9. Add the barium hydroxide 1 mL at a time for the first 25 mL. Ask the students to
describe what they see. (light begins to dim as solid forms)
10. Add the last 5 mL drop-by-drop until the endpoint is reached (phenolphthalein will
turn pink and remain pink for 30 seconds and the light will go out)
11. Ask your students to explain their observations.
12. Set the resultant material aside in a labeled container until the water evaporates off.
The resultant barium sulfate must be disposed of properly.
The two reactions above are straight forward acid/base neutralization reactions involving a
strong acid and a strong base, but, many other very important reactions fall under the category of
acid / base neutralization reactions. These include ester formation and amide formation which are
reactions associated with biological systems. The remainder of this lesson focuses on these
reactions.
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Esters are the result of weak acids, containing the carboxylic acid functional group,
combining with alcohols.
Functional Groups – an atom (or group of atoms and their bonds) that impart specific
chemical and physical properties to a molecule
Carboxylic Acid
Alcohol
Ester
The carboxylic acid provides the hydrogen ion and the alcohol provides the hydroxide ion for
water formation. Below is a reaction involving ester formation between salicylic acid and
methanol.
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Demonstration:
Demonstration Materials:
0.1 g salicylic acid
10 drops methanol
2 Droppers
Test tube
5 drops Conc. Sulfuric Acid
Spatula
Balance
Weigh boat or paper
250-mL beaker
Hot plate
Thermometer
Test tube clamps
Test tube rack
Demonstration Procedure
1. Prepare a warm water bath by filling a 250-ml beaker with water and heating the water to
60-65 C.
2. Mass out 0.1 g salicylic acid and place it in a test tube.
3. Add 10 drops of methanol.
4. After combining the alcohol and acid, swirl the test tubes around to mix the contents
thoroughly.
5. Using a new dropper add 5 drops of concentrated Sulfuric Acid to each test tube. Mix
each solution.
Caution: Concentrated sulfuric acid is corrosive and may cause severe burns. If exposed
to the acid, immediately wash the exposed area for several minutes.
6. Place the test tube in the hot water bath for 10 minutes. After 10 minutes, remove the test
tube carefully with a test tube holder and place it in the test tube rack.
7. Let it cool to room temperature before handling.
8. After the test tube has cooled, pass the ester around the class and have the waft to
determine smell.
Lab 2 – gives the student the opportunity to form esters.
Triglycerides, fats, are the result of ester formation between 3 fatty acids and glycerol which
contains 3 alcohol groups.
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Amide formation occurs between the hydrogen of an amine functional group and the
hydroxide of a carboxylic acid functional group.
Carboxylic Acid
Amine
Amide
Proteins and Enzymes result from amide formation between carboxylic acid functional groups
and the amine groups of amino acids.
Amino Acid
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Lesson 4 – Oxidation-Reduction Reactions (Redox Reactions)
Oxidation-Reduction reactions, also known as redox reactions, are reactions that involve a
transfer of electrons as the reaction proceeds from reactants to products. This lesson will
discuss two primary types of redox reactions. They include single displacement reactions and
combustion reactions. These two types of reactions will be studied individually.
Single displacement reactions
If you look back at the formula for a single displacement reaction, A + BY → AY + B, you
will note that:
The reactant that is in elemental form becomes a cation on the product side of the
reaction
The cation of the ionic compound on the reactant side is neutralized on the product side
as it becomes an element.
If you follow these alterations, it will be easy to identify this as a redox reaction and visualize the
electron transfer. The simplest way to follow the alteration is to assign oxidation states to the
elements that undergo the change. There are two rules of importance associated with single
displacement reactions.
1) An element in its standard state, meaning that it is neutral, has an oxidation state of zero.
2) A monoatomic ion has an oxidation state equal to its charge.
Let’s just look at an example:
Cu (s) + 2 AgNO3 (aq) → Cu(NO3)2 (aq) + 2 Ag (s)
By eliminating the nitrate ion, which does not undergo a change, the reaction becomes:
Cu (s) + 2 Ag+ (aq) → Cu2+ (aq) + 2 Ag (s)
Now it’s time to assign oxidation states to the reaction.
0
+1
+2
0
Cu (s) + 2 Ag+ (aq) → Cu2+ (aq) + 2 Ag (s)
Now to follow the alterations that occurred.
Note: Copper lost 2 electrons as it moved from reactant side to product side and each silver atom
gained 1 electron as it moved from reactant side to product side. Because one element gained
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electrons and one element lost electrons, there was a transfer of electrons and this reaction is a
redox reaction.
There are four key terms used to describe a redox reaction.
Element oxidized – the element that loses electrons as it moves from reactant side to
product side.
Element reduced – the element that gains electrons as it moves from reactant side to
product side.
Reducing reactant – the reactant that causes an element to be reduced. (The reducing
reactant will contain the element that is oxidized.)
Oxidizing reactant – the reactant that causes an element to be oxidized. (The
oxidizing reactant will contain the element reduced.)
Let’s apply this terminology to the reaction we have been looking at.
Combustion reactions of hydrocarbons
A combustion reaction is one in which a hydrocarbon is combined with oxygen. The most
common products of a combustion reaction are carbon dioxide and water though other
compounds are possible. Hydrocarbons are compounds that are primarily composed of
hydrogen and carbon, though other elements of sulfur, oxygen, and nitrogen, can be present.
All combustion reactions are redox reactions. The oxygen acts as an oxidizing reactant to
oxidize the carbon of the hydrocarbon. The hydrocarbon acts as the reducing reactant to reduce
the oxidation state of oxygen.
2 C8H18 (g)
+
25 O2 (g)
→ 16 CO2 (g) + 18 H2O (g)
Reducing reactant
oxidizing reactant
C oxidized
O reduced
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Demonstration:
Demonstration Materials
1 packet of active dry yeast
1 cup of very warm water (105oF – 115oF)
Kitchen thermometer
2 tablespoons of sugar
Large rubber balloon
1-pint to 1-liter empty water bottle
Procedure:
1. Add the 1 packet of dry yeast to the balloon.
2. Set the balloon aside.
3. Add the warm water to the bottle.
4. Add the 2 tablespoons of sugar to the bottle.
5. Attach the balloon to the mouth of the bottle.
6. Dump the yeast into the sugar solution and swish the bottle.
7. Set the bottle aside
8. After several minutes, you’ll notice the balloon standing upright.
9. Give the students the reaction and ask them to identify the element oxidized, the element
reduced, the oxidizing reactant and the reducing reactant
Observations: As the yeast combines with the sugar solution bubbling will occur. Let your
students know that bubbling is a sign of a chemical reaction. In this case the bubbling is the
result of carbon dioxide being produced from the decomposition of the sugar. Yeast is simply a
catalyst for this reaction. A catalyst is a material that speeds up reaction but its composition
remains unchanged.
3 C12H22O11 (aq) + 3 O2 (g) → 11 C2H5OH (aq) + 14 CO2 (g)
Lab 3 – is a dry lab to give the students and opportunity to identify oxidation states of elements,
the elements oxidized and reduced, and the oxidizing and reducing reactant.
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Overheads
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Lesson 1 – Definitions
Double Displacement Reaction – A reaction in which the cations of the
reactants swap their anionic partners
AB + CD → AD + CB
Single Displacement Reaction – A reaction in which an element replaces the
cation of an ionic compound
A + BY → AY + B
Synthesis Reaction – A reaction in which two or more reactants combine to
form a single product
A + B → AB
Decomposition Reaction – A reaction in which a single reactant separates to
form two or more products
AB → A + B
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Lesson 2 – Definitions
Precipitation Reaction – a reaction that produces a solid
product
Precipitate – solid product produced by a precipitation
reaction
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Lesson 3 – Definitions
Acid / Base Neutralization Reaction – reaction between an acid reactant and a
base reactant that produces water as one of the products
Functional Groups – an atom (or group of atoms and their bonds) that impart
specific chemical and physical properties to a molecule
Esters – Compounds that form between the alcohol function group of one
reactant and the carboxylic acid functional group of another reactant
Amide – Compound that forms between the amine functional group of a
reactant and the carboxylic acid functional group of the same reactant (in the
case of amino acids) or a second reactant
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Lesson 4 – Definitions
Oxidation-Reduction (Redox) Reaction – a reaction that involves a
transfer of electrons
Element Oxidized – the element that loses electrons to become more
positive
Element Reduced – the element that gains electrons to become more
negative
Oxidizing Reactant – reactant that causes an element to be oxidized
(contains the element reduced)
Reducing Reactant – reactant that causes an element to be reduced
(contains the element oxidized)
Combustion – The reaction of a hydrocarbon with oxygen to
typically produce carbon dioxide and water
Hydrocarbon – A substance primarily composed of carbon and
hydrogen
Catalyst – a substance that speeds up a reaction but does not
undergo a permanent change
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CoCl2 (aq) + 2 NaOH (aq) → Co(OH)2 (s) + 2 NaCl (aq)
Cu (s) + 2 AgNO3 (aq) → Cu(NO3)2 (aq) + 2 Ag (s)
K2Cr2O7 (aq) + Pb(NO3)2 (aq) → 2 KNO3 (aq) + PbCr2O7 (s)
The compound will be
Soluble (aq)
Soluble (aq)
Soluble (aq)
Soluble (aq)
Insoluble (s)
Insoluble (s)
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If it contains
Group 1, NH4+
NO3-, C2H3O2-, ClO4-, HCO3Halides (F-, Cl-, Br-, I-)
SO42O2-, OHAll other anions
Unless combined with
----------------------------Ag+, Pb2+, Hg22+
Ag+, Pb2+, Hg22+, Ca2+, Sr2+, Ba2+
Ca2+, Sr2+, Ba2+
----------------
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Carboxylic Acid
Alcohol
Ester
Amine
Amide
Amino Acid
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Cu (s) + 2 AgNO3 (aq) → Cu(NO3)2 (aq) + 2 Ag (s)
Cu (s) + 2 Ag+ (aq) → Cu2+ (aq) + 2 Ag (s)
0
+1
+2
0
+
2+
Cu (s) + 2 Ag (aq) → Cu (aq) + 2 Ag (s)
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2 C8H18 (g)
+
25 O2 (g)
→ 16 CO2 (g) + 18 H2O (g)
Reducing reactant
oxidizing reactant
C oxidized
O reduced
3 C12H22O11 (aq) + 3 O2 (g) → 11 C2H5OH (aq) + 14 CO2 (g)
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Laboratories
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Laboratory # 1
Preparation (per 50 groups)
0.1 M Copper Sulfate Pentahydrate – Dissolve 14.97 g of copper sulfate pentahydrate in enough
water to make 600 mL of solution.
0.1 M sodium carbonate – Dissolve 0.42 g of sodium carbonate in enough water to make 50 mL
of solution
0.1 M calcium chloride – Dissolve 0.55 g of calcium chloride in enough water to make 50 mL of
solution
0.1 M hydrochloric acid – Slowly combine 4.2 mL of concentrated sulfuric acid in enough water
to make 500 mL of solution
Materials per group
5 test tubes
Test tube rack
5 droppers
0.1 M copper sulfate pentahydrate
0.1 M sodium carbonate
0.1 M calcium carbonate
0.1 M hydrochloric acid
Magnesium strips
Steel wool
0.1 M potassium ferrocyanide
Solid copper sulfate pentahydrate
Test tube clamp
Bunsen burner
Lighter
Straw
Beaker
pH meter
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Procedures:
Experiment 1
1. Add 20 drops of 0.1 M copper sulfate pentahydrate to a clean test tube.
2. Add 20 drops of 0.1 M sodium carbonate to the test tube.
3. Record your observations and answer the questions.
Experiment 2
1. Add 5 mL of 0.1 M hydrochloric acid to a test tube.
2. Test the pH of the solution.
3. Add 0.4 g of magnesium to the test tube.
4. Allow the reaction to go to completion.
5. Test the pH of the solution.
6. Record your observations and answer the questions.
Experiment 3
1. Place an eraser full of solid copper sulfate pentahydrate in the bottom of a test tube.
2. Using the test tube clamps hold the bottom of the test tube over a Bunsen burner
flame.
3. Heat for 30 seconds to a minute.
4. Record your observations. (solid and rim of test tube)
5. Add a few drops of water to the test tube
6. Record your observations and answer the questions.
Experiment 4
1. Add 20 drops of copper sulfate pentahydrate to a clean test tube.
2. Add 20 drops of calcium chloride to the test tube.
3. Record your observations and answer the questions.
Experiment 5
1. Place a small piece of steel wool in the bottom of a test tube.
2. Cover the steel wool with 0.1 M copper sulfate pentahydrate.
3. Let the reaction sit for 10 minutes.
4. Record your observations.
5. Add 2 drops of 0.1 M potassium ferrocyanide.
6. Record your observations and answer the questions.
Experiment 6
1. Place water in a beaker.
2. Test the pH and record.
3. Blow bubbles for 1 minute into the water using a straw.
4. Test the pH and record.
5. Answer the questions.
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Data and Conclusions
Experiment 1
What does the copper sulfate pentahydrate solution look like?
What does the sodium carbonate solution look like?
What did you observe when the copper sulfate pentahydrate combine with the sodium carbonate?
Determine the state of matter for the reactants and the products in the reaction:
CuSO4 (_____) + Na2CO3 (_____) → CuCO3 (_____) + Na2CO3 (_____)
Circle the reaction type represented.
Single Displacement
Double Displacement
Synthesis
Decomposition
Experiment 2
What does the hydrochloric acid solution look like?
The initial pH of solution was _______________.
What does the magnesium look like?
What did you observe when the hydrochloric acid combined with the magnesium?
The final pH of the solution was _______________.
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Did the pH increase or decrease as the reaction proceeded?
The reaction studied was:
Mg (s) + 2 HCl (aq) → MgCl2 (aq) + H2 (g)
Circle the reaction type represented.
Single Displacement
Double Displacement
Synthesis
Decomposition
Explain why the pH increased or decreased given the reaction that occurred.
Experiment 3
What does the solid copper sulfate pentahydrate look like at the start of the reaction?
What does the solid look like after heating?
What did you observe around the rim of the test tube?
What does the solid look like after water was added to the test tube?
The reaction studied was:
.
CuSO4 5H2O (s) → CuSO4 (s) + 5 H2O (l)
Circle the reaction type represented.
Single Displacement
Reactions
Double Displacement
Synthesis
Decomposition
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Experiment 4
What does the copper sulfate pentahydrate solution look like?
What does the calcium chloride solution look like?
What did you observe when the copper sulfate pentahydrate combine with the calcium chloride?
Determine the state of matter for the reactants and the products in the reaction:
CuSO4 (_____) + CaCl2 (_____) → CuCl2 (_____) + CaSO4 (_____)
Circle the reaction type represented.
Single Displacement
Double Displacement
Synthesis
Decomposition
Experiment 5
What does the copper sulfate pentahydrate solution look like?
What does the steel wool look like?
What did you observe when the copper sulfate pentahydrate combined with the steel wool?
What did you observe when the potassium ferrocyanide was added?
If you were told that potassium ferrocyanide reacts with iron ion, what would you say was
present in solution in the end?
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The reaction studied was:
Fe (s) + CuSO4 (aq) → FeSO4 (aq) + Cu (s)
Circle the reaction type represented.
Single Displacement
Double Displacement
Synthesis
Decomposition
Experiment 6
The pH of the water at the start of the experiment was ___________________.
The pH after air was bubbled through the water was ___________________.
What would need to be present to cause the change in pH observed?
The reaction studied was:
H2O (l) + CO2 (g) → H2CO4 (aq)
Circle the reaction type represented.
Single Displacement
Reactions
Double Displacement
Synthesis
Decomposition
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Laboratory #2
Materials Needed (per group)
2 test tubes
Test tube rack
4 droppers
Test tube clamp
Thermometer
250-mL beaker
Hot plate
Concentrated sulfuric acid
Glacial Acetic acid
Isoamyl alcohol
99% Ethyl alcohol
Procedure
1. Obtain two test tubes and a test tube rack. Label the test tubes 1 and 2.
2. Prepare a warm water bath by filling a 250 ml beaker, heating the water to 60-65 C.
3. While the water is heating, use clean droppers to add the proper amounts of alcohol
and acid to the specified test tubes (refer to Table 1.1). Make sure to use clean a
clean dropper for each liquid. After adding the alcohol and acid, swirl the test tubes
around to mix the solutions.
4. Using a new dropper, add 5 drops of concentrated Sulfuric Acid to each test tube.
Mix each solution.
Caution: Concentrated sulfuric acid is toxic and may cause severe burns. If exposed
to the acid, immediately wash the exposed area for several minutes, and notify your
teacher.
5. Place both test tubes in the hot water bath for 10 minutes. After 10 minutes, remove
the test tubes carefully with a test tube holder and place them on the test tube rack.
Let them cool to room temperature before handling.
6. After the test tubes have cooled, carefully smell the ester by wafting (your teacher
will demonstrate the proper method for smelling chemicals). Record your
observations.
Table 1.1
Test Tube
1
2
Reactions
Alcohol
10 drops of Ethyl Alcohol
20 drops of Isoamyl Alcohol
Acid
10 drops of Acetic Acid
10 drops of Acetic Acid
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Data and Conclusions
Test tube 1 – Ethyl alcohol and acetic acid
What did you observe when you wafted the product?
Complete the reaction below.
+
H3C
O
H3C
OH
OH
Ethanol
Acetic Acid
Test tube 2 – Isoamyl alcohol and acetic acid
What did you observe when you wafted the product?
Complete the reaction below.
CH3
H3C
+
OH
Isoamyl Alcohol
Reactions
O
H3C
OH
Acetic Acid
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Laboratory #3
Ca (s) + 2H2O (l) → Ca(OH)2 (aq) + H2 (g)
Oxidation state of Ca in Ca
__________
Oxidation state of H in H2O is a +1.
Element Oxidized
__________
Element Reduced
__________
Oxidation state of Ca in Ca(OH)2
__________
Oxidizing Reactant
__________
Oxidation state of H in H2
__________
Reducing Reactant
__________
Zn (s) + 2HCl (aq) → ZnCl2 (aq) + H2 (g)
Oxidation state of Zn in Zn
__________
Oxidation state of H in HCl is a +1.
Element Oxidized
__________
Element Reduced
__________
Oxidation state of Zn in ZnCl2
__________
Oxidizing Reactant
__________
Oxidation state of H in H2
__________
Reducing Reactant
__________
CH4 (g) + 2O2 (g) →
Element Oxidized
__________
Element Reduced
__________
Oxidizing Reactant
__________
Reducing Reactant
__________
Reactions
CO2 (g) + 2H2O (l)
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2Al ( s ) + Fe 2 O 3 ( s ) → Al 2 O 3 ( s ) + 2Fe ( l )
Oxidation state of Al in Al
__________
Element Oxidized
__________
Oxidation state of Fe in Fe2O3
__________
Element Reduced
__________
Oxidation state of Al in Al2O3
__________
Oxidizing Reactant
__________
Oxidation state of Fe in Fe
__________
Reducing Reactant
__________
C10H8 (g) + 12 O2 (g) → 10 CO2 (g) + 4 H2O (g)
Element Oxidized
__________
Element Reduced
__________
Oxidizing Reactant
__________
Reducing Reactant
__________
Reactions
Page 40