Name:_____________________________________________________________ Period:_________ Date:______

Unit 2: Matter and Change

Unit Objectives: Classify types of matter Draw particle diagrams to represent different types of matter Recognize various techniques that can be used to separate matter Describe changes of state Describe basic chemical reactions

Unit Vocabulary:

Matter

Element

Compound

Mixture

Heterogeneous Mixture

Homogeneous Mixture

Pure Substance

Particle Diagram

Chromatography

Filtration

Distillation

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Matter

Do Now: Complete the following Pre-test. Put T for true statements and F for false statements in the space provided.

____1. Matter is anything that has mass.

____2. A spaceship ceases to be matter when it is in space because it has no weight.

____3. Air can be weighed.

____4. Heat has weight.

____5. Both air and heat are matter.

____6. Matter takes up space.

____7. Air occupies space.

____8. Light takes up space.

____9. Light is matter.

____10. Matter can be in different shapes.

____ 11. Matter can be in different phases.

____12. Water has no definite shape therefore it is not a matter.

____13. A solid has a definite shape.

____14. You cannot change the shape of a solid.

____15. You can compress water to force it to occupy less space.

____16. A glass is inverted over a basin of water and slowly inserted into the water. However,

the water does not enter the glass. This experiment proves that air takes up space.

____17. Air will expand to fill the space available.

____18. Matter can exist in three states: solid, liquid and gas.

____19. Iron combines with oxygen in moist air to form iron oxide, or rust. This change is

called a chemical change.

____20. When water changes to steam it undergoes a chemical change.

Matter vs. Not Matter2

Can you recognize matter when you see it? What makes matter different from that which is not matter? A light bulb, for example, is matter. The electricity that makes it glow is not. What is the difference? All matter has certain characteristics in common that separate it from whatever is not matter. Can you tell which is which? Get together with your lab group and try. You will be given a card with a list of six items. Three are matter and three are not.

1. Try to classify the items on the card properly. Write your conclusions in the table below.

MATTER NOT MATTER

2. Describe the characteristics all the items you classified as MATTER have in common that make them different from the items you classified as NOT MATTER.

_________________________________________________________________________________________________________________________

Matter- Anything that has mass and volume (takes up space)

1. An element is the simplest form of matter.

• It cannot be decomposed• Elements are made up of tiny particles called atoms• There are 7 diatomic elements

2. A compound is a substance made up of two or more elements in a fixed proportion• compounds are made up of particles called molecules

3. A mixture is a combination of two or more substances (elements or compounds) • It can be separated into components by physical methods• It can be homogeneous or heterogeneous

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MatterAnything that has mass and

volume (takes up space)

PURE SUBSTANCES (each piece looks the same

– PURE!)-each piece has exact same

composition.

MIXTURES (each piece is different – not pure)

Can NOT be separated by physical means

CAN be Separated by PHYSICAL means

ELEMENT (simplest form of matter)

Example: Na, Cl2

HETEROGENEOUS MIXTURE (not uniform throughout— a pattern)

Example: Italian dressing, concrete, soil, chocolate chip cookie

Hetero = opposite

HOMOGENEOUS MIXTURE (uniform throughout—distinct pattern)

Example: saltwater, iced tea

Homo = same

COMPOUND or MOLECULE(2+ different elements chemically combined)

Example: NaCl (table salt), H2O (water)

Can NOT be separated by chemical means

Separated by chemical means,

only

Same composition throughout

Different composition throughout

Particle Diagram

Particle Diagram

Particle Diagram

Particle Diagram

Matter ActivityItem Observations Element, Compound or

Mixture?Defend your answer

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2

3

4

5

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7

8

9

10

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Questions:1. How could you tell a substance is an element?

2. What phases can elements be in?

3. How could you tell a substance is a compound?

4. What phases can compounds be in?

5. How could you tell a sample is a mixture?

6. What phases can mixtures be in?

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Elements, Compounds, and Mixtures

There are 2 types of PURE SUBSTANCES. They can be either an element or a compound.

1.) Element : It is the simplest form of matter that can exist under lab conditions.

Elements cannot be separated into simpler substances.

They are represented by a symbol; ONE Capital Letter. (Each capial letter represents one

element.) Sometimes a lowercase letter is used as well.

Elements are shown on the Periodic Table

There are only 92 naturally-occurring elements. EXAMPLES: Br, Ag, O, N, H etc.

• There are some elements (only 7!) that exist in nature only as diatomic elements.

Br2, I2, N2, Cl2, H2, O2, F2

That means there are two atoms of one kind stuck (bonded) together so you should always use a co-efficient of 2 when you see them in an equation!

Here are two examples of particle diagrams that would represent diatomic elements:

2.) Compound: Two or more elements chemically combined with each other. Compounds can be separated into simpler substances.

A compound has a fixed composition. It is always the same.

Formulas for compounds are written in a certain way.

EXAMPLES: H2O CO2 NaCl The little numbers directly following an element symbol are called subscripts.

This tells you how many atoms of that element are in the compound.

EXAMPLES: H2O CO2 NaCl (2 H’s and 1 O) (1 C and 2 O’s) (1 Na and 1 Cl)

A common mistake by students such as yourself happens in compounds like CO2. The 2 goes ONLY TO THE O… NOT TO THE C (as shown above in the formula and below in the picture.)

We can draw particle diagrams of these three compounds as follows:

H2O CO2 NaCl

Compounds are made up of molecules (a specific ratio of chemically combined atoms).

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A mixture is a blend (physical change) of two or more substances.

Homogeneous Mixtures are uniform throughout Examples: salt in water, air

Heterogeneous Mixtures are non-uniformExamples: chunky chicken soup, dirt in water

Homogeneous and Heterogeneous are both relative terms. This means that some of your answers will depend on your prior experiences and knowledge. As long as you can defend/explain why you answered your question the way you did, it is acceptable.

Na + S is a mixture. Likewise Na2S + KCl is a mixture

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Matter Practice

Directions: After each statement below, choose the letter of the word that applies from the list below.

a. matter e. compoundb. substance f. heterogeneous mixturec. mixture g. homogeneous mixtured. element

_____ 1) cannot be chemically decomposed

_____2) components can be combined in any ratio

_____ 3) components must be combined in a specific, fixed ratio that can never change

_____ 4) has mass and volume

_____5) chemically combined to produce new substance with totally new properties

_____ 6) substances are physically combined, unevenly spread throughout

_____7) substances are physically combined, evenly spread throughout

_____ 8) combining substances where each substance retains its individual properties

_____ 9) manganese

_____ 10) Al2(SO4)3

_____ 11) sand in water

_____ 12) physically combined, physically separated

_____ 13) since the substances retain their individual properties, they can be separated based on their

unique physical properties

_____ 14) can’t be physically decomposed, but can be chemically decomposed

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Separating MixturesSince mixtures are made by physically combining 2 or more pure substances together, we use physical techniques to separate them. The technique used depends on what phase or state of matter the components are.

1. Fitration-solid and a liquid2. Phase change-distillation, evaporation, etc. 3. Separatory funnel-two immiscible liquids 4. Various physical means such as magnet, tweezers, sieve -two solids5. Chromatography – density and particle size differences

Separation Apparatus Type of Separation (Physical or Chemical)

Description of Technique

What types ofMatter will it separate?

Filtration

PHYSICAL

Undissolved particles remain on filter paper (filtrate flows through filter paper)

HETEROGENEOUS mixtures (ex: sand

water)

*Can also centrifuge

Watch Glass Evaporation

PHYSICAL

Separate solute (dissolved solid) from solvent (liquid) by boiling solution

Solute escapes Very limited

precision

HOMOGENEOUS mixture (solution)

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Distillation

PHYSICAL

Separate solute from solvent by boiling solution and recondensing in receiving flask (both solute and solvent captured)

Separate 2 or more liquids with different boiling points

HOMOGENEOUS (can use to remove

impurities from water)

Chromatography

PHYSICAL

Separates particles based on:

1) size2) solubility

HOMOGENEOUS

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Check your Understanding:

For each picture below:a) Identify the separation technique from the list above. b) Select the property that allows for the technique to work, from among these choices:

1. Differences in particle “attractiveness” or “electrical stickiness” of the mixture components, allowing them to be separated when solvent and some other medium (like paper) “compete” for the mixture components.

2. Differences in particle size of the mixture components.

3. Differences in particle boiling points of the mixture components.

Technique: ___________

Property allowing it to work: # ___

Technique: ________________ Technique:______________

Property allowing it to work: # ____ Property allowing it to work: #____

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Particle Diagrams of Matter

Particle diagrams are used to illustrate states and forms of matter. Typically, a particular type of atom is shown as a small circle of one color or shade.

A diagram of an element would contain only one type of atom.

A compound would contain two or more types of atoms attached in a fixed ratio

A mixture would contain one or more elements and one or more compounds.

Check your understanding:

IDENTIFY THE FOLLOWING AS A PURE ELEMENT, PURE COMPOUND OR MIXTURE OF ???

___________ __________ ____________ __________ __________

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Check your Understanding:

1. Two substances, A and Z, are to be identified. Substance A can not be broken down by a chemical change. Substance Z can be broken down by a chemical change. What can be concluded about these substances?

a. Both substances are elements. b. Substance A is an element and substance Z is a compound.c. Both substances are compounds. d. Substance A is a compound and substance Z is an element.

2. Base your answer to the question on the information below.The particle diagrams below represent the reaction between two nonmetals, A2 and Q2

Using the symbols A and Q, the chemical formula of the product could be written asa) AQb) A2Qc) AQ2

d) A2Q2

3. Which statement describes a chemical property of oxygen?

a) Oxygen has a melting point of 55 K.b) Oxygen gas is slightly soluble in water.c) Oxygen can combine with a metal to produce a compound.d) Oxygen gas can be compressed.

4. Which two substances can not be broken down by chemical change?a) C and CuO b) CO2 and CuOc) C and Cu d) CO2 and Cu

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5. Which particle diagram represents one pure substance, only?

6. Which substance can be decomposed by chemical change?a) berylliumb) methanolc) boron d) magnesium

7. Which species represents a chemical compound?a) N2 b) Nac) NH +

d) 4. NaHCO3

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Phase Changes

Directions:Using the diagram above as a reference, draw a particle diagram for a solid, liquid, and gas of the same substance.Use at least 6 particles. Also, identify the changes in the states of matter (as represented by the arrows between states).

SOLID (s) LIQUID (l) GAS (g)

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Almost all substances can be made to change between the 3 phases, simply by altering the temp. The classification of matter into solids, liquids and gases is termed as physical classification of

matter.

Characteristics of solids 1. Solids maintain their volume independent of the size or shape of the container in which they are

placed in.2. Solids are rigid and have definite shape.3. Solids diffuse very slowly compared to liquids and gases, due to close packing 4. Solids are incompressible 5. Most solids melt on heating, and some sublimate.6. Solids have very high mass to volume ratio or density compared to liquid or gases.

Characteristics of liquids Moderate forces of attraction exist between the molecules of a liquid. The molecules in a liquid are in a state of random motion although the extent is much smaller in

comparison to gases. The average Kinetic energy of the molecules in a liquid is proportional to the temperature.

Characteristics of gases Gases maintain neither volume nor shape and completely fill the container in which they are

introduced. Gases expand when heated Gases diffuse rapidly; we can smell perfume even when applied at a distance very fast Gases are highly compressible; if pressure is increased then volume decreases Almost all gases except a few are colorless

Properties SOLID LIQUID GAS

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SHAPE(definite, takes

shape of container)

VOLUME(definite, takes

volume of container)

PARTICLE MOVEMENT

(Vibrates, moves freely)

DENSITYDistance between

particles

Attraction between particles

(Strong, Weak)

PARTICLE DIAGRAM

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Heating Curve Worksheet

Below is a diagram showing a typical heating/cooling curve for water. It reveals a wealth of information about the structure and changes occurring in water as it is heated or cooled through all three phases of matter at different temperatures. At the top of the diagram are pictures representing the typical particle arrangement as substances change through their states.

1. There is something clearly wrong about the particle spacing in the pictures at the top. What is it? (Hint… the pictures were drawn for most materials, not for water specifically).

2. Identify by letter (A-E) in which section the following are found:

a. _______ Freezing (if cooling) b. _______ Particles farthest apart

c. _______ Boiling d. _______ Particle motion is most restricted

e. _______ Heat of fusion f. _______ All areas where energy change is potential only

g. _______ Heat of vaporization h. _______ All areas where particles move past each other

i. _______ Least kinetic energy j. _______ All areas where kinetic energy is changing

k _______ most potential energy l. _______ All areas where phase changes occur

m. _______ All areas in which the heat is making the particles move faster

n. _______ All areas in which the heat is breaking the attractions or bonds between particles

o. _______ All areas in which the particles are not changing their speed

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Heat removed

Now try an unlabeled heating curve for water without pictures and see how well you do!

1. First identify the sections where the following phases are found:

a. _______ gas b. _______ solid c. _______ liquid

d. _______ solid and liquid e. _______ liquid and gas

2. Identify by letter (A-E) in which section the following are found:

a. _______ Freezing (if cooling) b. _______ Particles farthest apart

c. _______ Boiling d. _______ Particle motion is most restricted

e. _______ Heat of fusion f. _______ All areas where energy change is potential only

g. _______ Heat of vaporization h. _______ All areas where particles move past each other

i. _______ Least kinetic energy j. _______ All areas where kinetic energy is changing

k _______ most potential energy l. _______ All areas where phase changes occur

m. _______ All areas in which the heat is making the particles move faster

n. _______ All areas in which the heat is breaking the attractions or bonds between particles

o. _______ All areas in which the particles are not changing their speed

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Heat removed

Heating / cooling curve for water

Physical and Chemical Properties

Do Now: Read the following and fill in the information:

Properties of MatterPhysical Observable or measurable porperties

Ex) hardness, color, smell, mass, melting pointChemical Describes how a substance reacts OR does not react with

other substance(s)Ex) Copper reacts with Nitric Acid, Cu does not react with hydrochloric acid (HCl)

Identify the following as being physical or chemical properties.

________________1. The mass of copper wire is 255 g.

________________2. The boiling point of ethyl alcohol is 77°C.

________________3. Baking soda reacts with vinegar to make carbon dioxide gas.

________________4. The density of mercury is 13.6g/mL.

________________5. The solubility of sodium chloride in water is 40g/100mL of water.

Physical and Chemical Changes

Properties of Matter Changes in MatterPhysical Observable or measurable properties

Ex) hardness, color, smell, mass, melting pt.

Altering a substance without changing its composition or properties; the original material can be recovered. (Still the same substance but in a different form)

Chemical Describes how a substance reacts OR does not react with other substance(s)Ex) Copper reacts with Nitric Acid, Cu does

not react with hydrochloric acid (HCl)

A new substance is made that has a different composition and properties; the original material can sometimes (not usually) be recovered, but usually only with great difficulty. (New substanced formed)

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Reactions

In order to keep track of how things are changing. We have to look at the before and the after. Chemists do this by writing an equation, similar to what you have done in math class. The only real difference, is that you replace the = with !

Some important vocab: An equation describes a chemical change or reaction. The equation shows substances which react

with each other once mixed to form other substances. Reactants (the substances that we start with, or in other words that react) are on the left side of

the equation. Products (the substances that we end with, or in other words are produced) are on the right side

of the equation. Reactants and products are separated by an arrow. It shows the direction of the equation. System is another word for reaction that is often used by chemists.

For example:I am starting with Na and Cl and I want to change it into NaCl. We can do a reaction to make this happen and we can record the change with an equation.

2Na + Cl2 2 NaCl + heat

1) How many different substances are described on the “left side” of the equation?

2) How many different substances described on the “right side” of the equation?

3) What does this tell me? I can look at an equation to see if a change is chemical or physical. In this case, since a new substance is formed, it is a chemical change.

***Note that the number and kind of atoms on the left side of the equation equal the number and kind of atoms on the right side of the equation. Only the arrangement of the atoms has changed in going from reactants to products.

The equality of atoms or matter on either side of a chemical equation is called a balanced equation; it illustrates the principle of the Conservation of Matter.

Conservation of Matter: Matter can neither be created or destroyed , but the atoms in the reactants can become rearranged in a chemical change. Weighing the system before and after a chemical change is a way to prove this.

Note: Conservation of Matter is also called Conservation of Mass. They are interchangable terms. To see if an equation has conservation of matter or mass, we look for the one that is balanced.

For example:Pick the change (equation) that correctly shows a conservation of mass:

1) NaCl Na + 2 Cl

2) 2 NaCl 2 Na + Cl

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3) NaCl 2 Na + Cl2

4) 2 NaCl 2 Na + Cl2

Conservation of Energy...Exo vs. Endothermic Changes (Reactions)

Just as there is a Law of Conservation of Matter, there is a Law of Conservation of Energy.

Law of Conservation of Energy- Energy can neither be created or destroyed.

Usually there is an energy change involved in either a chemical change or a physical change.

Reaction How I Know Direction of Heat Flow

Type of Energy Change

Reactant or Product (in Equation)

Requires Heat

Feels cold around the

change

From the surroundings

into the system

Endothermic Reactant

Releases Heat

Feels hot around the

change

From the system into the surroundings

Exothermic Product

Check your understanding:State whether the following reactions or processes are physical or chemical changes and if they are exothermic or endothermic:

1. Burning charcoal glows bright red until it turns to ash

2. To convert one gram of ice to water, 334 J of heat must be added.

3. SO3(g) + H2O (l) H2SO4(aq) + heat

4. CaCO3(s) + heat CaO(s) + CO2(g)

5. Neutralization of a strong acid with a base gives a warm solution.

6. Barium hydroxide mixed with ammonium chloride yields ammonia gas and the flask gets cold.

7. When heated to a high temperature, iron melts.

8. Water freezes to ice at 0 degrees Celsius.

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Changes Written as Equations

Do Now: Complete the chart to the best of your ability.

Situation Type of Change (P or C)

Explanation (Write a sentence.)

Cooking an egg

Digesting your lunch

Mixing the ingredients for a

cake

Rusting of a nail

Dew forming on the lawn

Melting ice off a windshield

Combustion (burning) of

gasoline

Purifying salt water by evaporation

CO2 (s) CO2 (g)

H2O (g) H2O (l)

H2ONaCl (s) NaCl

(aq)

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Unit 2 Matter: General Chemistry Review

ELEMENTS, COMPOUNDS, AND MIXTURES

1. Matter is anything that has a mass and takes up space. An element is the simplest form of matter which cannot be broken down any further. Elements are listed on Table S and the periodic table. Their symbols start with an uppercase letter.

a. Which of the following is not matter? _____________________

Magnesium Calcium Carbonate Salt water Heat

b. Which of the above is an element? _____________________

2. Compounds are composed of two or more elements. They can only be decomposed chemically. Elements and compounds are also known as substances.

a. Which of the choices in number one was a compound? ________________________

b. How can compound be broken down? __________________________________________________

c. Which of the choices in question one are substances? ______________________________________

3. Mixtures are physical combinations of two or more substances (elements and/or compounds). Mixtures can be homogeneous (completely mixed, cannot see the parts) or heterogeneous (unevenly mixed, can see the parts). Mixtures can be separated by physical means.

a. Label each as homogeneous or heterogeneous:

Sand: ____________________ Brass: ______________________________

Milk: ____________________ Oil and water: ________________________

4. Compounds must be separated chemically but mixtures can be separated easily using physical methods.

a. Match each method with its name.

Distillation Separated by differences in particle size

Filtration To pour off the top layer of an uneven mixture

Decant Separated by differences in boiling point.

b. Which of the above processes only work if the mixture is heterogeneous? _____________________

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c. Label the following as element (E), compound (C), or mixture (M).

__________________________________________________________________________________________

SOLIDS, LIQUIDS, AND GASES

5. A solid has a definite shape and volume. Solids are arranged in a geometric pattern. Liquids have a definite volume but take the shape of the container they are in. Gases have an indefinite shape and volume; they take the shape and volume of the container. Gases are easily compressed.

a. Draw particle diagrams for a solid, liquid, and a gas using at least 5 particles:

b. Which has a definite shape?

HCl(g) H2O(l) Cu(s)

c. Which has a definite volume?

LiF(g) Br2(l) Mg(s)

6. Vapors are the gas phase of substances that are normally solid or liquid at room temperature.

a. Which can be a vapor?

Carbon dioxide ______ Water _____ Oxygen _____

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__________________________________________________________________________________________

CHANGES IN THE LAB

7. Physical changes are changes where the substance retains its properties. Chemical changes will make substances change into new substances and change properties.

a. Label the following as physical (P) or chemical (C) properties:

Texture ____ flammability ____ boiling point: ____

Odor ____ color ____ chemical composition: ____

b. Label the following as physical (P) or chemical (C) changes:

Corrosion: ____ melting: ____ mixing: ____

Freezing: ____ cutting: ____ decaying: ____

8. In chemical reactions mass is conserved.

a. Can you form or destroy matter? _______________________________________________________

b. Mass of reactants is ______________ mass of products. (Greater than, Equal to, or less than?)

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