teks 8.9 a c and d

TEKS 8.9 A, C, D

TEKS 8.9 A, C AND DIt was here just a moment

ago!

TAKS Objective 3 – The student will demonstrate an understanding of the structures and properties of matter.

Learned Science Concepts:

Matter is composed of atoms.

Substances have chemical and physical properties.

Complex interactions occur between matter and energy.

TEKS Science Concepts 8.9The student knows that substances have chemical and physical properties. The student is expected to:

(A)demonstrate that substances may react chemically to form new substances;

(C) recognize the importance of formulas and equations to express what happens in a chemical reaction; and

(D) identify that physical and chemical properties influence the development and application of everyday materials such as cooking surfaces, insulation, adhesive, and plastics.

TAKS Objective 3 page 1

TEKS 8.9 A, C, D

OverviewStudents will learn to identify evidence of chemical change. By combining a variety of substances, they will demonstrate different chemical changes that produce change in color, change in temperature, production of gases, and the production of precipitants. Students will also learn what a chemical formula means and how scientists use formulas.

Instructional StrategiesStudents will be involved in hands-on inquiry to demonstrate chemical changes. Hands-on models will be used to build a concrete picture of chemical formulas.

Objectives1. The student will demonstrate chemical change as evidenced by a

change in color.

2. The student will measure temperature change as the result of a chemical reaction.

3. The student will demonstrate a chemical reaction that produces gases.

4. The student will demonstrate a chemical change that results in the formation of a precipitant.

5. The student will use models to explain chemical formulas.


TEKS 8.9 A, C, D

For Teachers Eyes OnlyChemical Reactions

A chemical reaction, also called a chemical change, is material changing from a beginning mass to a resulting substance. The process involves one or more reactants yielding one or more products different from the reactants. The characteristic of a chemical reaction is that new material or materials are made and the original material disappears. A chemical change could involve molecules attaching to each other to form larger molecules, molecules breaking apart to form two, or more, smaller molecules, or rearrangement of atoms within molecules. In order to make transformations possible, chemical reactions usually involve the making or breaking of chemical bonds. This does not mean that new elements have been made. In order to make new elements, the nuclear contents must change with the addition or subtraction of protons. An important aspect of the definition is that a chemical reaction does not change the atomic nucleus in any way, only the interaction of the electron clouds of the involved atoms. Thus nuclear reactions are not chemical reactions.

Definition: A chemical change occurs whenever compounds are formed or decomposed.

reactants disappear as chemical change occurs.

products appear as chemical change occurs.

catalysts speed up the reaction, but aren't produced or consumed.

Microscopic view: A chemical change occurs whenever there is a rearrangement of atoms that makes or breaks chemical bonds.

Chemical Equations

A chemical equation or formula is a way to describe what goes on in a chemical reaction. Chemical equations are written with symbols. There is an arrow pointing to the right that indicates the result of the chemical change or the products. The materials to the left of the arrow are the reactants. There are such things as reversible reactions, reactions in which the products reassemble to become the original products. Reversible reactions are symbolized in chemical equations by a double-headed arrow.


TEKS 8.9 A, C, D

Chemical Bonding

Chemical bonds form to lower the energy of the system in such a way the components of the system become more stable. G. N. Lewis (1916) suggested that bonds form to enable elements to attain a "noble gas configuration". Chemical bonding involves sharing or transfer of electrons, resulting in a more stable system. There are several types of chemical bonds. Three basic types are:

ionic bonding, bonding between metals and non-metals involving the transfer of electron(s). The substances are usually solid at room temperature.

covalent bonding, bonding between non-metals and non-metals involving sharing of electrons. The substances are usually gases or liquids at room temperature.

metallic bonding, which simplistically can be considered as a combination of both. They are generally solids at room temperature.

Types of Chemical Reactions

SYNTHESIS REACTIONS

A synthesis reaction might be symbolized by:

A + B AB

A synthesis reaction occurs when two materials, elements or compounds, come together to make a single product.

2 H2 + O2 2 H2O

What would you see in a ‘test tube’ if you were witness to a synthesis reaction? You would see two different materials combine. A single new material appears.

DECOMPOSITION REACTIONS

A single reactant comes apart into two or more products, symbolized by:

XZ X + Z

In a “test tube” you would see a single material coming apart into more than one new material. For example heating sodium


TEKS 8.9 A, C, D

bicarbonate releases water and carbon dioxide and sodium carbonate.

6 NaHCO3 3 Na2CO3 + 3 H2O + 3 CO2

SINGLE REPLACEMENT REACTIONS

A single replacement reaction occurs when silver nitrate solution has a piece of copper placed into it. The solution begins to turn blue and the copper seems to disappear. A silvery-white material appears.

2 AgNO3 + Cu Cu(NO3)2 + 2 Ag

DOUBLE REPLACEMENT REACTIONS

Let’s take an example.

AgNO3 + KCl AgCl(s) + KNO3

The above equation tells only part of the story. Dissolved silver nitrate becomes a solution of silver ions and nitrate ions. Potassium chloride ionizes the same way. When the two solutions are added together, the silver ions and chloride ions find each other and become a solid precipitate. (They ‘rain’ or drop out of the solution, this time as a solid.) Since silver chloride is insoluble in water, the ions take each other out of the solution.

Ag+ + (NO3)- + K+ +Cl- AgCl + K+ + (NO3)-

Another way to remove ions from a solution is to combine an acid and a base. The two will neutralize forming water and a salt. One more way for the ions to be taken out of the water is for some of the ions to escape as a gas.

Conclusion

Chemical reactions are often accompanied by the appearance of gas, fire, precipitate, color, light, sound, or odor. These phenomena are related to energy and properties of the reactants and products. For example, the oxidation of propane releases heat and light, and a rapid reaction is an explosion. We study properties of substances so that we know how to make use of them.


TEKS 8.9 A, C, D

It is important to remember that in a when a chemical change occurs and energy is released or is absorbed, no loss in total molecular weight occurs. In some reactions heat is given off (exothermic reactions), and in others heat is absorbed (endothermic reactions). Furthermore, the new substances formed differ from the original substances in the energy they contain. Reversible reactions are those in which the chemical change taking place may be paralleled by another change back to the original substances.

Adapted from online lectures of Clive Buckley

North East Wales Institute of Higher Education


TEKS 8.9 A, C, D

Student Misconceptions Misconception

Chemical changes are separate changes in substances

Science ConceptChemical changes involve interactions between molecules of the substances.

Rebuild ConceptAfter the student has observed the characteristics of two separate substances, combine them to cause a chemical change. Examine the new substance. Point out that the new substance has very different characteristics than either of the individual substance. Also point out that the new substance cannot be separated back into its original 2 substances.

MisconceptionReal chemicals are found in the chemistry laboratory and not around the house.

Science ConceptChemicals that are found around the house are usually more concentrated than teachers use with the students in lab due to safety issues at school.

Rebuild ConceptLet students take some litmus paper home to test various solutions found around their homes.


TEKS 8.9 A, C, D

Student Prior KnowledgeThe student knows that substances have physical and chemical properties and those substances can combine chemically to form new substances. (TEKS 6.7 and 7.7)


TEKS 8.9 A, C, D

5 E’sEngageEngage 1

Demonstration: Balloon Gas

1. Before class place a couple of spoons of baking soda into a balloon. Wipe off any evidence of balloon tampering.

2. Do this class demonstration without prior explanation. Pour about 20 ml white vinegar into the balloon using a funnel. Immediately clamp or tie the balloon shut.

3. Hold the balloon up for the class to observe it blowing itself up.

4. Ask students what they think they just witnessed. Tell students they will be demonstrating and observing chemical changes in the explore activities.

ExploreExploration 1

Activity: Red light – Green light

Class Time: 10 minutes

Objective: The student will demonstrate chemical change as evidenced by a change in color.


TEKS 8.9 A, C, D

Materials

VinegarAmmonia2 small beakerscabbage juice or universal indicatorGoggles

Preparation Red cabbage juice can be made by placing chopped red cabbage with water in a blender. Strain the blended juice. The cabbage can also be cooked and the juice strained. Keep in the refrigerator to keep from spoiling- will last ~10 days.

6. Place about 10 ml of cabbage juice in the portion cup.

7. Place about 5 drops of ammonia into the portion cup with cabbage juice. Observe what happens.

8. Place about 10 drops of vinegar into the portion cup. Observe what happens.

Exploration 2

Activity: For the rust of my life


Objective: The student will measure temperature change as the result of a chemical reaction.

Process Skills:

TEKS 8.4 (A) – The student is expected to collect record, and analyze information using thermometers or computer probes.

Materials:

ThermometerSteel wool (soaked in vinegar)GogglesJar with lid


TEKS 8.9 A, C, D

Teacher Preparation:

Students will need just enough steel wool to wrap around the bulb of their thermometer. Soak steel wool in vinegar overnight in large beaker. Have students pick up their piece of steel wool only when ready to use it. It is the reaction of the soaked steel wool and the air that is producing the heat in this reaction.

Procedure:

1. Record the temperature of the air _________________

2. Wrap the steel wool around the bulb of the thermometer.

3. Record the temperature every 30 seconds for 5 minutes

4. What happens?

Exploration 3

Activity: Take a Powder


Objective: The student will measure temperature change as the result of a chemical reaction.

Process Skills:

TEKS 8.4 (A) – The student is expected to collect record, and analyze information using thermometers or computer probes.

Materials:

ThermometerBaking powderBaking SodaVinegarWaterGoggles2 plastic spoons2 portion cups or small beakers

Procedure:


TEKS 8.9 A, C, D

1. Place 2 spoons of baking powder and the thermometer in the portion cup.

2. Add 20 ml water and stir.

3. Record the temperature after 15 seconds.

4. Place 2 spoon of baking soda and the thermometer in a clean portion cup.

5. Add 10 ml of vinegar.

6. Record the temperature after 15 seconds.

7. Compare the two processes.

Exploration 4

Activity: Clabbered Clumps


Objective: The student will demonstrate a chemical change that results in the formation of a precipitant.

Materials:

MilkWhite vinegarGogglesPortion cup or beaker

Procedure:

1. Place 20 ml of milk in the portion cup.

2. Add 20 ml white vinegar and stir.

3. Observe what happens.

Exploration 5

Activity: Witches Brew



TEKS 8.9 A, C, D

Objective: The student will demonstrate a chemical reaction that produces gases.

Materials:

Baking sodaWhite vinegar colored with green food coloringGogglesPlastic spoonLarge beaker

Procedure:

4. Place 2 spoons of baking soda in the beaker.

5. Add 20 ml of the vinegar.

6. Observe what happens.

Exploration 6

Activity: Bubble Bubble Toil and Trouble


Objective: The student will demonstrate a chemical reaction that produces gases.

Materials

250 mL BeakerNine-volt battery or Lantern BatteryTwo 14-18 Gauge wires to connect to terminals of battery (strip off 0.5 cm of insulation from both ends of wire)200 mL Distilled waterSalt

Procedure As a result of this activity both hydrogen and chlorine gases will be produced. The chorine gas might be distinguished by smell.

1. Connect the wires to the battery

2. Fill the beaker with water about 2/3 full.

3. Place the battery wires into the water. DO NOT let the ends of the wires touch. What happens? Nothing

4. Put 10-30 ml of salt in water and stir until dissolved.


TEKS 8.9 A, C, D

5. Place the battery wires back in the water. DO NOT let the ends of the wires touch. What happens? It bubbles.

6. The chlorine gas may give off a noticeable odor.

Exploration 7

Go to the following website:

http://www.learnalberta.ca/content/secs/html/matter_and_chemical_change/ChemicalAndPhysicalChange/index.html

In the lower right hand corner, click on the word, “guide” and then close the blue introduction frame. You may close the blue introduction frame by clicking on the “X” located at the top right hand corner of the blue introduction frame.

View each of the 10 videos which are titled below. Answer the following questions for each video listed below. Remember the neumonic:

– P lease- Precipitate (2 clears make cloudy)– E xcuse- Energy change (heat, light, sound, electricity)– C oughs- Color change (unexpected)– S neezes- Smell Change– B urps- Bubbles or fizzing (gas produced)

Video 1 - Blazing Glory

1. What happens when glycerine is added to the container of potassium permanganate? Smoke, fire, bubbles

2. Is this a physical or chemical change? Chemical

Video 2 – Tiny Bubbles

1. What is the first measuring tool used in this experiment? Digital balance

2. What is added to the beaker? Nitric acid and copper3. What happens? The solution bubbles and the temperature goes up.4. Is this a physical or chemical change? Chemical

Video 3 – Gone but Not Lost

1. How much water is in the test tube? 5 ML2. What is added to the test tube? Sodium acetate trihydrate and water3. What happens? The solution bubbles and the temperature goes up.




TEKS 8.9 A, C, D


Video 4 – Shower of Yellow

1. What containers are shown in this video? Beaker, flask, test tube, graduate cylinder

2. Is this a physical or chemical change?

Video 5 – Seeding Crystals

1. What happens when sodium acetate is added to water? White crystals are formed and a drop of condensate forms at the bottom of the test tube.


Video 6 – Swell Marshmallows

1. What happens to the marshmallow when the pressure is increased? They puff up

2. What happens to the marshmallow when the pressure is decreased? They shrink down

3. Is this a physical or chemical change? Physical

Video 7 – Sugar Power

1. What happens when sugar and potassium chlorate are combined? nothing

2. What happens when sulphuric acid is added to sugar and potassium? It flames


Video 8 – Cold but Sublime

1. What happens when dry ice is added to water? It melts2. Is this a physical or chemical change? Physical

Video 9 – Now That’s A Gas

1. What happens when water and phenolphthalein indicator are combined? nothing

2. What happens when water and phenolphthalein solutions are combined with calcium carbide? The solution turns fink and fizzes



TEKS 8.9 A, C, D

Video 10 – Trading Places

1. What happens when copper chloride is combined with aluminum? It bubbles and fizzes

2. Is this a physical or chemical change? chemical

ExplainAsk students what evidence suggested a chemical change in each of the explore activities. Students should have observed smell changes, color changes, energy changes (heat, light, sound, electricity, etc), bubbles/fizzing &/or formation of precipitants.

ElaborateElaboration 1

Activity: Abracadabra

Class Time: 1 class period

Objective: The student will systematically test for evidence of a chemical reaction.

Materials

Bottle A (contains tap water)Bottle B (contains white vinegar)Bottle C (contains sodium thiosulfate- 62 g sodium thiosulfate to 500 mL water = 0.5M solution)Powder 1 (baking soda)Powder 2 (sodium chloride)Powder 3 (calcium chloride)Litmus paperClear plastic cups or beakers


TEKS 8.9 A, C, D

Plastic spoonsThermometerAbracadabra Data Sheet (see Black Line Masters)

Preparation: Before class label the solutions and powders as shown in the materials list. The actual name should be unknown to students.

Procedure: Students should investigate what happens when 2 unknown substances are mixed. Only two substances should be mixed (ex. 10 ml from bottle A could be mixed with a spoon for powder 1). Students should record changes in temperature, pH (litmus is red in acid, blue in base), color, formation of gas, or formation of precipitate.

Elaboration 2

Activity: Sweet Models


Objective: The student will use models to explain chemical formulas.

Materials

playdough spheres (red, yellow, blue), or gumdrops, m&m’s, skittlesPaper place mat

Procedure

1. Make four spheres of each color playdough. Each blue sphere represents one hydrogen atom, red spheres represent oxygen atoms and yellow spheres represent carbon atoms.

2. Attach the spheres as described to build molecules. Fill in your data table as you go.

a. water: H2O: connect 2 hydrogens to one center oxygen.

b. carbon dioxide: CO2: connect 2 oxygens to one center carbon.

c. methane: CH4: connect four hydrogens to one center carbon.


TEKS 8.9 A, C, D

DATA

Chemical name

Chemical formula

Number of atoms in compound

Hydrogen Carbon Oxygen Total

Water

Carbon dioxide

Methane

1. In a molecule of fruit sugar, C6H12O6, how many carbon atom are there? Hydrogen? Oxygen?

2. Which formulas represent compounds? Elements? (NaCl, Ag, Co, CO, SO2, AgBr)

3. Nitrogen in the air is two nitrogen atoms attached together, N2. Is this nitrogen a compound or element? How do you know?


TEKS 8.9 A, C, D

So Happy Together!

Most solids, liquids and gases exist because of their ability to combine, or chemically bond, with other elements to make new substances called compounds. Bonds are created when chemical reactions occur, rearranging atoms and share or transfer electrons. Once bonds are made, atoms hang on tightly to their new partners. It is difficult to split new compounds apart.

Each of these groupings shows the atoms that create compounds. Write the formula that shows the makeup of the compound.

__________ 1. hydrogen chloride __________ 2. ammonia

__________ 3. water __________ 4. hydrogen peroxide

__________ 5. carbon dioxide __________ 6. sand (silicon dioxide)


H Cl N H

H

H

HOH HOOH

OCOSiO O

TEKS 8.9 A, C, D

__________ 7. diphosphorous pentoxide

__________ 8. chalk (calcium carbonate)

__________ 9. baking soda (sodium bicarbonate

__________ 10. methane

__________ 11. salt (sodium chloride)

__________ 12. carbon monoxide

_________ 13. silver nitrate _________ 14. nitrogen dioxide


OO

O

O

OPP

ClNa

H

H

H

H

C

OC

O

O

O

NAg

O ON

O

O

CHNa

O

O

CCa

OO

TEKS 8.9 A, C, D

Elaboration 3

Activity: Irreversible Consequences

Class Time: 20 minutes (not allowing for drying time

Materials

Baking sodaWhite vinegarPlastic spoonEvaporating dish

Procedure:

1. Place about ½ spoon full of baking soda in an evaporating dish. Add 2 mL of white vinegar.

2. Allow the mixture to dry.

3. Examine the result and compare it with baking soda. Do they look the same?

4. To find out, add 2 mL of vinegar to the substance remaining in the dish and observe.

Questions:

1. Did a chemical reaction occur in step 1? Explain. Yes, it was an endothermic reaction with fizzing. Carbon dioxide was produced.

2. Are the chemical properties of the residue the same as those of baking soda? Explain. No, adding more vinegar does not create the same reaction.

Elaboration 4

Take it home: Chemistry at home

Objective: Identify that physical and chemical properties influence the development and application of everyday materials such as cooking surfaces, insulation, adhesive, and plastics

If a student looks carefully, they will spot many chemical reactions going on right in their own kitchen. Have students make a list of 10 chemical reactions observed at home. Upon returning to class, have the students write a list of ideas they have developed about chemical reactions freely in a paragraph without worrying about punctuation, spelling and grammar.


TEKS 8.9 A, C, D

Elaboration 5

Objective: Observe physical and chemical properties of chemicals.

The students will use technology to view videos associated with physical and chemical properties of chemicals (see blackline master). Go to the following website: http://www.learnalberta.ca/content/secs/html/matter_and_chemical_change/ChemicalAndPhysicalChange/index.html

Elaboration 6

Objective: Recognize compounds, interpret chemical formulas and recognize balanced equations.

The student will use prior information they have learned about elements to recognize compounds and chemical formulas. The student will fill in the missing piece to create a balanced equation (see blackline master)..

Evaluate1. How many molecules of copper are produced from two molecules of

Cu2O? 4

2. What happens to atoms in a chemical reaction?

3. What physical properties can change in a chemical reaction?




TEKS 8.10 ATAKS Objective 3 page 23

TEKS 8.10 A

Mixing it up Lab Guide

In this lab, we’re going to combine different substances and see if a chemical change takes place. To do this, we need to remember the five events that evidence a chemical change (remember our mnemonic – Please Excuse Coughs, Sneezes, and Burps): (1) the formation of a precipitant, (2) energy release or absorbed, (3) unexpected color change, (4) smell change, and (5) the formation of bubbles (which tells us that a gas has been formed). Additionally, we’re going to learn to test the pH of liquids by using strips of litmus paper, which change different colors depending on the pH of the liquid in which they are immersed.

Record the color of each substance in the following table:

Vinegar Sodium Thiosulfate

Water Morton Iodized Salt

Baking Soda

Use the litmus paper strips to determine the pH of each individual liquid:

Vinegar Sodium Thiosulfate

Tap Water Morton Iodized Salt

Baking Soda

8 7

When measuring out substances, use the following quantities: Vinegar – 10 drops; Sodium Thiosulfate – 10 drops; Tap Water – 10 drops; Morton Iodized Salt – ½ teaspoon; Baking Soda – ½ teaspoon.


TEKS 8.10 A

TRIAL 1: Next, you will choose two substances to combine. You may either combine a liquid with a liquid or a solid with a liquid. Circle YES or NO for the questions in each trial, and complete any follow-up questions, if necessary.

First Substance ____________________ Second Substance ____________________

Was a precipitant formed? (Remember, you can only have a precipitant if you are combining liquids) YES NO

If yes, was a solid or a cloudy liquid formed?

Was energy released or absorbed? YES NO

If yes, what was the form of the energy released or absorbed?

Did you see a color change? YES NO

If yes, what color is the product?

Does the combination smell different from the initial substances? YES NO

Were bubbles formed? YES NO

What is the pH of the combination?

TRIAL 2: Next, you will choose two substances to combine. You may either combine a liquid with a liquid or a solid with a liquid.






TEKS 8.10 A

















TEKS 8.10 A












Circle the five combinations that you tested:

Vinegar + Sodium Thiosulfate

Water + Vinegar Sodium Thiosulfate + Water

Vinegar + Salt Water + Salt Sodium Thiosulfate + Salt

Vinegar + Baking Soda Water + Baking Soda Sodium Thiosulfate + Baking Soda


TEKS 8.10 A

Sweet Models


Objective: The student will use models to explain chemical formulas.

Materials

playdough spheres (red, yellow, blue), or gumdrops, m&m’s, skittlesPaper place mat

Procedure

1. Make four spheres of each color playdough. Each blue sphere represents one hydrogen atom, red spheres represent oxygen atoms and yellow spheres represent carbon atoms.

2. Attach the spheres as described to build molecules. Fill in your data table as you go.

a. water: H2O: connect 2 hydrogens to one center oxygen.

b. carbon dioxide: CO2: connect 2 oxygens to one center carbon.

c. methane: CH4: connect four hydrogens to one center carbon.


TEKS 8.10 A

DATA

Chemical name

Chemical formula

Number of atoms in compound

Hydrogen Carbon Oxygen Total

Water

Carbon dioxide

methane

1. In a molecule of fruit sugar, C6H12O6, how many carbon atom are there? Hydrogen? Oxygen?

2. Which formulas represent compounds? Elements? (NaCl, Ag, Co, CO, SO2, AgBr)

3. Nitrogen in the air is two nitrogen atoms attached together, N2. Is this nitrogen a compound or element? How do you know?


TEKS 8.10 A

So Happy Together!

Most solids, liquids and gases exist because of their ability to combine, or chemically bond, with other elements to make new substances called compounds. Bonds are created when chemical reactions occur, rearranging atoms and share or transfer electrons. Once bonds are made, atoms hang on tightly to their new partners. It is difficult to split new compounds apart.

Each of these groupings shows the atoms that create compounds. Write the formula that shows the makeup of the compound.

__________ 1. hydrogen chloride __________ 2. ammonia

__________ 3. water __________ 4. hydrogen peroxide

__________ 5. carbon dioxide __________ 6. sand (silicon dioxide)


H Cl N H

H

H

HOH HOOH

OCO SiO O

TEKS 8.10 A

__________ 7. diphosphorous pentoxide __________ 8. chalk (calcium carbonate)

__________ 9. baking soda (sodium bicarbonate

__________ 10. methane

__________ 11. salt (sodium chloride) __________ 12. carbon monoxide

_________ 13. silver nitrate _________ 14. nitrogen dioxide


OO

O

O

OPP

ClNa

H

H

H

H

C

OC

O

O

O

NAg

O ON

O

O

CHNa

O

O

CCa

OO

TEKS 8.10 A

Compounds, Chemical Formulas, and Chemical Equations

For each of the following:

(a) List the elements.

(b) Indicate how many atoms there are for each element on each side of the equation.

(c) Complete the missing information so that each side of the equation in balance.

1. 2C2H6 + 7O2 → 4CO? + 6H2O

Ethane + Oxygen yields Carbon Dioxide + Water

(a)

(b)

(c)

2. ?Al + 3O2 → 2Al2O3

Aluminum + Oxygen yields Aluminum Oxide

(a)

(b)

(c)


TEKS 8.10 A

3. CO2 + 4H2 → CH4 + H?O

Carbon Dioxide + Hydrogen yields Methane + water

(a)

(b)

(c)

4. ?Mg + P4 → 2Mg3P2

Magnesium + Phosphorus → Magnesium Phosphide

(a)

(b)

(c)

5. 2H2 + O? → 2H2O

Hydrogen + Oxygen yields water

(a)

(b)

(c)


TEKS 8.10 A

6. K2O + H2O → ?KOH

Potassium oxide + water yields potassium hydroxide

(a)

(b)

(c)

7. I2 + 2Na2S2O3 → 2NaI + Na?S4O6

Iodine + Sodium Thiosulphate yields Aluminum Oxide + Copper

(a)

(b)

(c)

8. ?Al + 3CuO → Al2O3 + 3Cu

Aluminum + Copper Oxide yields Aluminum Oxide + Copper

(a)

(b)

(c)


TEKS 8.10 A

9. C?H8 + 5O2 → 3CO2 + 4H2O

Propane + Oxygen yields Carbon Dioxide + water

(a)

(b)

(c)

10. 3H2 + N2 → 2NH?

Hydrogen + Nitrogen yields ammonia

(a)

(b)

(c)

11. List the names of five elements from problems 1-10 above.

12. List the names of five compounds from problems 1-10 above.

13. Describe in words how to calculate the number of hydrogen and oxygen atoms for the following: 6H2O


TEKS 8.10 A

Chemical Formulae and Equations

For each of the following, identify the elements present and the number of atoms of each element in the molecule.

1. Aspirin - C9H8O4

Elements Present Number of Atoms of each Element

2. Tylenol - C8H9NO2


3. Coke - C17H21NO4


4. Bleach - NaOCl


5. Caffeine - C8H10N4O2


6. Hydrogen peroxide - H2O2


7. Rubbing alcohol - C6H12O6


TEKS 8.10 A


8. Sugar - NH3


9. Table salt - NaCl


10. Benzoyl peroxide - C14H10O4


11. wintergreen flavor - C8H8O3


12. Lotion - CH4N2O



TEKS 8.10 A

13. Ethanol - C2H5OH


14. Theobromine (main ingredient of chocolate) - C7H8N4O2.


15. Lycopene (bright red pigment in a tomato) - C40H56


16. Corn Syrup - C6H12O6 + H2O


Vocabulary:

An atom is a unit of matter, the smallest unit of an element, having all the characteristics of that element and consisting of a dense, central, positively charged nucleus surrounded by a system of electrons.

A molecule is the smallest physical unit of an element or compound, consisting of one or more like atoms in an element (e.g., H, O, or N etc.) and two or more different atoms in a compound (e.g.,. H2O, CO2, etc.).


http://en.wikipedia.org/wiki/Hydrogen

http://en.wikipedia.org/wiki/Carbon

TEKS 8.10 A

Use the formulae given the answer the questions concerning the formulae.

Water → Hydrogen + Oxygen

2H2O → 2H2 + O2

1. How many molecules are on the left side of the equation? ____2. How many molecules are on the right side of the equation? ____3. How many H atoms are on the left side of the equation? ____4. How many H atoms are on the right side of the equation? ____5. How many molecules are in O2? ____6. How many O atoms are in 2H2O? ____7. How many H atoms are in 2H2? ____

Methane + Oxygen → Carbon Dioxide + Water

CH4 + 2O2 → CO2 + 2H2O

8. How many molecules are on the left side of the equation? ____9. How many molecules are on the right side of the equation? ____10. How many C atoms are there in CH4? ____11. How many H atoms are there in CH4? ____12. How many H atoms are there in 2H2O? ____13. How many O atoms are there in 2H2O? ____

Sodium + Water → Sodium Hydroxide

Na2O + H2O → 2NaOH

14. How many molecules are on the left side of the equation? ____15. How many molecules are on the right side of the equation? ____16. How many Na atoms are there in Na2O? ____17. How many O atoms are there in Na2O? ____18. How many Na atoms are there in 2NaOH? ____19. How many O atoms are there in 2NaOH? ____20. How many H atoms are there in 2NaOH? ____

carbon dioxide + water + light energy → glucose + oxygen

6CO2 + 6H2O + photons → C6H12O6 + 6O2

21. How many molecules are on the left side of the equation? ____22. How many molecules are on the right side of the equation? ____23. How many molecules are in 6CO2? ____24. How many molecules are in C6H12O6? ____25. How many H atoms are in 6H2O? ____26. How many O atoms are in 6CO2? ____27. How many C atoms are in C6H12O6? ____


TEKS 8.10 A

28. Draw 2NaOH:


TEKS 8.10 A

Chemical Equations

VocabularyMolecule – two or more atoms combinedElement – a pure substance made of only one kind of atomCompound – a substance made of more than one kind of atomPhysical Change – a change in which no new substances are producedChemical Change – a change in which new substances are produced

A chemical equation describes what happens in a chemical reaction (a reaction in which a chemical change occurs). It is important to note that in a chemical reaction:

(a) atoms are NOT destroyed(b) atoms are NOT created(c) atoms are NOT changed into other kinds of atoms

So if none of these things happen in a chemical reaction, just what do we mean when we say “new substances are produced in a chemical reaction”? We mean that the atoms in the molecules on the left side of the arrow are rearranged into the molecules on the right side of the arrow.

A correctly written chemical equation will be balanced. This means that there are equal numbers of each kind of atom on both sides of the arrow.

Directions:(1) For each of the following, count up the number of atoms of each element on both sides of the equation to determine whether each equation is balanced.(2) Also, draw the molecules present on each side of equation in the space provided.

1. The following chemical equation describes the hydrolysis of water in which water is broken down into hydrogen gas and oxygen gas.

Water yields Hydrogen and Oxygen

2H2O → 2H2 + O2

H = H = Is the equation balanced?

O = O =

→ +


O

HH

O

HH

H H

H H

O

O

TEKS 8.10 A

2. The following chemical equation describes carbonic acid breaking down into water and carbon dioxide (the bubbles in soda).

Carbonic Acid yields Water and Carbon Dioxide

H2CO3 → H2O + CO2

Is the equation balanced?

3. The following equation describes the combustion of propane gas in which propane and oxygen form carbon dioxide and water.

Propane and Oxygen yield Carbon Dioxide and Water

C3H8 + 5O2 → 3CO2 + 4H2O


4. The following equation describes the photosynthesis, in which carbon dioxide and water react to form glucose (a simple sugar), oxygen gas, and water.

Carbon Dioxide and Water and Light Energy yield Glucose and Oxygen and Water

6CO2 + 12H2O + photons → C6H12O6 + 6O2 + 6H2O



TEKS 8.10 A

Chemistry Computer LabGo to the following website:


In the lower right hand corner, click on the word, “guide” and then close the blue introduction frame. You may close the blue introduction frame by clicking on the “X” located at the top right hand corner of the blue introduction frame.

View each of the 10 videos which are titled below. Answer the following questions for each video listed below. Remember the neumonic:

– P lease- Precipitate (2 clears make cloudy)– E xcuse- Energy change (heat, light, sound, electricity)– C oughs- Color change (unexpected)– S neezes- Smell Change– B urps- Bubbles or fizzing (gas produced)

Video 1 - Blazing Glory

1. What happens when glycerine is added to the container of potassium permanganate?


Video 2 – Tiny Bubbles

3. What is the first measuring tool used in this experiment?

4. What is added to the beaker?

5. What happens?


Video 3 – Gone but Not Lost

7. How much water is in the test tube?

8. What is added to the test tube?

9. What happens?





TEKS 8.10 A

Video 4 – Shower of Yellow

11. What containers are shown in this video?


Video 5 – Seeding Crystals

13. What happens when sodium acetate is added to water?


Video 6 – Swell Marshmallows

15. What happens to the marshmallow when the pressure is increased?

16. What happens to the marshmallow when the pressure is decreased?


Video 7 – Sugar Power

18. What happens when sugar and potassium chlorate are combined?

19. What happens when sulphuric acid is added to sugar and potassium


Video 8 – Cold but Sublime

21. What happens when dry ice is added to water?



TEKS 8.10 A

Video 9 – Now That’s A Gas

23. What happens when water and phenolphthalein indicator are combined?

24. What happens when water and phenolphthalein solutions are combined with calcium carbide?


Video 10 – Trading Places

26. What happens when copper chloride is combined with aluminum?



TEKS 8.10 ATAKS Objective 3 page 47

teks 8.9 a c and d

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