Chemical Reactions(s) + 2 NaCl (aq) Precipitation reactions involving two ionic compounds are always...

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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:


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.

http://www.metacafe.com/watch/894804/uncontrollable_magnesium_reaction_in_dry_ice/

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The most common way to illustrate this type of reaction is via the general reaction:

A + B → AB

Demonstration:


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:


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 Oxidation-

Reduction 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:


and


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 If it contains Unless combined with

Soluble (aq) Group 1, NH4+ ---------------

Soluble (aq) NO3-, C2H3O2

-, ClO4

-, HCO3

- ---------------

Soluble (aq) Halides (F-, Cl

-, Br

-, I

-) Ag

+, Pb

2+, Hg2

2+

Soluble (aq) SO42-

Ag+, Pb

2+, Hg2

2+, Ca

2+, Sr

2+, Ba

2+

Insoluble (s) O2-

, OH- Ca

2+, Sr

2+, Ba

2+

Insoluble (s) All other anions ----------------

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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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:


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.

http://upload.wikimedia.org/wikipedia/commons/b/be/Fat_triglyceride_shorthand_formula.PNG

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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:


By eliminating the nitrate ion, which does not undergo a change, the reaction becomes:

Cu (s) + 2 Ag+ (aq) → Cu

2+ (aq) + 2 Ag (s)

Now it’s time to assign oxidation states to the reaction.

0 +1 +2 0

Cu (s) + 2 Ag+ (aq) → Cu

2+ (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 – 115

oF)

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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Precipitation Reaction – a reaction that produces a solid

product

Precipitate – solid product produced by a precipitation

reaction

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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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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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Reactions



K2Cr2O7 (aq) + Pb(NO3)2 (aq) → 2 KNO3 (aq) + PbCr2O7 (s)

The compound will be If it contains Unless combined with

Soluble (aq) Group 1, NH4+ ---------------

Soluble (aq) NO3-, C2H3O2

-, ClO4

-, HCO3

- ---------------

Soluble (aq) Halides (F-, Cl

-, Br

-, I

-) Ag

+, Pb

2+, Hg2

2+

Soluble (aq) SO42-

Ag+, Pb

2+, Hg2

2+, Ca

2+, Sr

2+, Ba

2+

Insoluble (s) O2-

, OH- Ca

2+, Sr

2+, Ba

2+

Insoluble (s) All other anions ----------------

Reactions

http://upload.wikimedia.org/wikipedia/commons/b/be/Fat_triglyceride_shorthand_formula.PNG

Reactions

Carboxylic Acid

Alcohol

Ester

Amine

Amide

Amino Acid

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Cu (s) + 2 Ag+ (aq) → Cu

2+ (aq) + 2 Ag (s)

0 +1 +2 0

Cu (s) + 2 Ag+ (aq) → Cu

2+ (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.


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


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.


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.


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)



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?


CuSO4 . 5H2O (s) → CuSO4 (s) + 5 H2O (l)



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Experiment 4


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 (_____)



Experiment 5


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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Fe (s) + CuSO4 (aq) → FeSO4 (aq) + Cu (s)



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?


H2O (l) + CO2 (g) → H2CO4 (aq)



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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 Alcohol Acid

1 10 drops of Ethyl Alcohol 10 drops of Acetic Acid

2 20 drops of Isoamyl Alcohol 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.

CH3

OH

CH3

OH

O

+

Ethanol Acetic Acid

Test tube 2 – Isoamyl alcohol and acetic acid

What did you observe when you wafted the product?

Complete the reaction below.

OH

CH3

CH3

CH3

OH

O

+

Acetic AcidIsoamyl Alcohol

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Laboratory #3

Ca (s) + 2H2O (l) → Ca(OH)2 (aq) + H2 (g)

Oxidation state of Ca in Ca __________ Element Oxidized __________

Oxidation state of H in H2O is a +1. 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 __________ Element Oxidized __________

Oxidation state of H in HCl is a +1. Element Reduced __________

Oxidation state of Zn in ZnCl2 __________ Oxidizing Reactant __________

Oxidation state of H in H2 __________ Reducing Reactant __________

CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O (l)

Element Oxidized __________

Element Reduced __________

Oxidizing Reactant __________

Reducing Reactant __________

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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 __________

Chemical Reactions(s) + 2 NaCl (aq) Precipitation reactions involving two ionic compounds are always...

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Transcript of Chemical Reactions(s) + 2 NaCl (aq) Precipitation reactions involving two ionic compounds are always...