UNIT THREE: MATTER AND CHANGE

UEQ

What defines the matter around us?

LEQ: What forms does matter take?

PROPERTIES OF MATTER

STATES OF MATTER****Solid: maintains a fixed volume and shape.

Amorphous or crystalline . Not compressible.**Liquid: maintains a fixed volume but takes

the shape of the container. Viscous flow

**Gas: occupies the entire volume available, random motion. Flows with elastic collisions. Compressible

**Plasma: occurs at high temperatures

PHASE CHANGES W/ ENERGY

PHASE CHANGE DIAGRAM

QUESTIONS: Identify each of the following to its state

of matter.1. Random motion and fills the container.2. Very compressible.3. Amorphous4. Defined volume but takes the shape of

the container.5. Defined volume and flows.6. Defined shape and volume.7. Not compressible.8. Elastic collisions.9. Viscous.10. Crystalline

LEQ: Why do we say that ALL things are made of matter?

PHYSICAL AND CHEMICAL PROPERTIES

Physical Properties:

examples: texture, shape, size, color, odor, volume, mass, weight, malleability, ductility, conductivity, temperature and density

`Chemical Properties: example: color change, energy given

off or absorbed, gas given off, odor change, light, solid produced from solution

PHYSICAL AND CHEMICAL CHANGES

Physical Change: when objects undergo a change that does not change their chemical nature. Involves a change in physical properties. NO change in composition.

Chemical Change: substances are changed into different substances. The composition of the substance changes.

CHARACTERISTICS OF CHEMICAL PROPERTY: Chemical property: interaction that

result in the change in the composition of matter. Combines into one or more different substances.

Indicators of a Chemical Change 1. heat production (energy

change) 2. gas production (bubbles), odor

3. change in color 4. precipitation 5. reacts with or inability to

react

INTENSIVE AND EXTENSIVE PROPERTIES

Intensive Properties: Properties that do not depend on how much of the substance you have. Independent on amount.

Examples: Temperature, pressure, density, boiling point, solubility, color

Extensive Properties: Depend on the amount of the substance.

Examples: Mass  and  volume  

QUESTIONS: IDENTIFY EACH OF THE FOLLOWING AS A PHYSICAL OR CHEMICAL PROPERTY:

Silver tarnishes in the air. Gold remains untarnished after 100 years under

seawater. Sliver hammered into the shape of a ring. Barium boils at 725oC. Argon is an inert gas and will not react with other

gases. Lead is easier to bend than iron. Potassium metal is spontaneous in water and

oxygen. Graphite and diamonds are both carbon but a

diamond will not write. Two clear liquids are mixed and an orange color

is produced. Digestion

LEQ: How is matter combined to form the world around us?

PROPERTIES OF AN ELEMENT:Element:

a pure chemical substance composed of atoms with the same number of protons

not easily broken down into it’s smaller parts

very distinctive properties

properties are different from the compounds they make up

Gold

Mercury

Sodium

Chlorine Gas

PROPERTIES OF COMPOUNDS:COMPOUND:

has a constant composition with fixed ratios of elements

physical properties such as boiling point or melting point of pure substances are invariant (unchanging).

Example: pure water boils at 100 °C

Table salt: NaCl

Pure Water: H2O

Carbon Dioxide: CO2

WHAT ARE MIXTURES?

  MIXTURE : •a combination of two or more substances that are not chemically united

• do not exist in fixed proportions

•most natural substances are mixtures

PROPERTIES OF MIXTURESMIXTURES can be physically separated

into pure compounds or elements.

just about everything that you can think of is probably a mixture.

may exhibit a changing set of physical properties.

Concrete

Sea Water

Vegetable soup

HETEROGENEOUS MIXTUREHeterogeneous: indicates difference

consists of visibly different substances or phases

the four phases are gas, liquid, solid, and plasma

Example: beach sand, vinegar and oil salad dressing, air with clouds

Italian Salad Dressing

Jello with Fruit

Air with Clouds

EXAMPLES OF HETEROGENEOUS MIXTURES:

"Dancing Raisins" shows liquid, solid, and gas substances in a heterogeneous mixture.

•Vinegar + Baking Soda – forms a heterogeneous solution: there are liquids and gases present.

HOMOGENEOUS MIXTURES

Homogeneous: indicates sameness

has the same uniform appearance and composition throughout.

are commonly referred to as solutions.

Examples: corn oil , white vinegar , sugar solution, air (with no clouds)

Kool-Aid

Swimming Pool Water

Air with no Clouds

SOLUTIONS Are distinguished by particle size.

Homogeneous solutions have particles which are the size of atoms or molecules - too small to be seen.

Homogeneous solutions are two or more substances in a single phase.

The concentrations may be expressed using a variety of measures.

IDENTIFY THE FOLLOWING AS HETEROGENEOUS OR HOMOGENEOUS: An alloy (a solid solution of several

metals and non-metals). 70% isopropyl alcohol gasoline bread latex paint beef stew air seawater a pile of rusty iron filings concrete

DENSITY Density= Mass/Volume

Describes the degree of compactness of a substance – ( how closely packed together the atoms of an element, molecule or compound are.)

LEQ: How is matter expressed in chemistry?

CHEMICAL EQUATION expression of the interaction between

substances. To yield

2NaCl(aq) + H2SO4 (aq) Na2SO4 (aq) + 2HCl(aq)

Reactants ProductsSubscripts: # of atoms in the

compound SubscCoeffiecents: the # of compounds or molecules present. Called ‘a Mole’

Physical States: (aq) dissolved in water, aqueous, (s) solid, (l) liquid, and (g) gas

WHAT DOES AN EQUATION TELL YOU? The number of compounds or molecule

presentThis is the coefficient or ‘the Mole’

The number of each atom in the compound.This is the subscripts

Physical state (solubility rules) Examples: How many copper atoms in Cu2SO4 ?

2 How many copper atoms in 3Cu2SO4?

6

1. How many oxygen in Fe(NO3)3 ?

92. How many oxygen in 2Fe(NO3)3?

183. What is the physical state of: MnCrO4 (s)?

(s)

4. How many sulfates are in 3Cu2SO4 ?

35. How many hydroxides are present in

Mg(OH)2 ?

2

LAW OF CONSERVATION OF MATTER

Fundamental principle that states that matter cannot be created or destroyed.

In a chemical reaction the sum of all the masses of the substances involved in the reaction (reactants) is equal to the sum of all of the masses of the substances produced by the reaction (products) .

No matter is gained or lost.

QUESTIONA strip of iron with a mass of 15.72 g is placed

in a solution containing 21.12 g of copper (II) sulfate. After the reaction, the iron strip has a mass of 8.33 g. The mass of the copper formed in 8.41g. What mass of the iron (II) sulfate has been formed in the reaction?

Chemical reaction:Fe + CuSO4 Cu + FeSO4

Mass-Action expression:Massiron+ Mass copper sulfate= Masscopper + Mass iron sulfate

(15.72g – 8.33g) 21.12g 8.41g ?

To find:Massiron + Masscopper sulfate - Masscopper = Massiron

sulfate

(15.72g – 8.33g) + 21.12g - 8.41g = 20.10 g

PRACTICE PROBLEMS:

1. A reaction of 22.85g of sodium hydroxide with 20.82 g of hydrogen chloride gives off 10.29g of water. What mass of sodium chloride is formed in the reaction? The reaction is:

NaOH + HCl NaCl + H2O

2. Suppose 5 g of calcium hydroxide and 10 g of ammonium chloride are mixed in a test tube then heated until no more ammonia is given off. The remaining calcium chloride in the test tube has a mass of 10.27 g. What is the total mass of ammonium and water vapor produced in the reaction? The reaction is:Ca(OH)2 + 2NH4Cl 2NH3 + 2H2O + CaCl2

NOTE: The number of Moles of each species!!!!

3. A sealed glass tube contains 2.25g of copper and 3.32g of sulfur. The mass of the tube and the contents is 18.48g. When the sealed glass tube is heated, a reaction between the copper and the sulfur forms copper (II) sulfide (CuS). All of the copper reacted and there is 1.14 g of sulfur remaining. Predict the mass of the sealed glass tube and its contents after the reaction.

Cu + S CuS.

PERCENT (%) MASS The mass of the part (in grams) divided by the mass of

the whole (in grams) times 100.

% mass = mass of part / mass of whole X 100

Example: Hot Chocolate with Marsh Mellows mass of marsh mellows: 2.5 grams mass of hot chocolate with marsh mellows: 105.26 grams % Mass of Marsh mellow: (2.5 g / 105.26 g) X (100) = 2.38 %

LAW OF DEFINITE PROPORTIONS Compounds are formed in exact

proportion to the mass of the compound.

Law of Definite Proportions = % Mass

SAMPLER By mass: 100 g of H2O will always be

combined by mass with 11.19 g of hydrogen and 88.81 g of oxygen.

Given the mass of one molecule of H2O is 18g.

Given the mass of one mole hydrogen is 1.00797gGiven the mass of one mole of oxygen is 15.9994 gThen one mole of H2O is:

2(1.00797g) / 18g = 11.19 g 15.9994g / 18g = 88.81g

100g

1. Given 25 g of a compound that is composed of 6.77 g of tin and 18.23 g of bromine. What is the percent be mass of each element in the compound?

% by mass of Sn = mass of Sn/ mass of cpd X100

% = 6.77 g / 25g x 100 % = 27.1 % Sn

% by mass of Br = mass of Br/ mass of cpd x 100

% = 18.23 g / 25 g x 100

% = 72.9 % Br

EXAMPLES:1. A 134.5 g sample of aspirin is made up of

6.03 g of hydrogen, 80.70 g of carbon, and 47.77 g oxygen. What is the percent by mass of each element in aspirin?

2. A 2.89 g sample of sulfur reacts with 5.72 g of copper to form a black compound. What is the percentage composition of the compound?

3. Aluminum oxide has a composition of 52.9% aluminum and 47.1% oxygen by mass. If 16.4 g of aluminum reacts with oxygen to form aluminum oxide, what mass of oxygen reacts?

LAW OF MULTIPLE PROPORTIONS When the same elements are involved in the

formation of more than one compound, each MUST combined in the relationship of a small whole number.

Cpd 1: Mass X / Mass Y = Mass 1

Cpd 2: Mass Y / Mass X = Mass 2

Mass 1 / Mass 2 = Whole #Then the combination of elements X and Y can

form more than compound.

SAMPLER MULTIPLE PROPORTIONS

It is believed that phosphorous and chlorine combine to form two different compounds. In one compound, 3.88 g of P combines with 13.28 g Cl. In the other compound, 1.32 g P combines with 7.56 g Cl. Use the law of Multiple Proportion to support the formation of these two compounds.

ELEMENTS: CATEGORY OF SUBSTANCES.

1. Elements: simplest form of matter represented in symbols.

2. Symbols: a. First letter of the nameb. First two letters of the namec. Places and namesd. Latin and Greek

PERIODIC TABLE A expression of the regular repeating

properties to elements. Dmitri Mendeleev: first table arranged

by atomic mass. Robert Mosley: arranged the periodic

table according to the atomic number (the number of protons in the nucleus).

Periods: horizontal row Groups or Family: vertical columns

COMPOUNDS

Category of substances: Chemical combination of two or

more elements. Specific arrangement of elements Law of Definite Proportion:

compounds are always composed of the same element in the same proportions by mass.

H2O NaClC6H12O6

2:1 1:1 6:12:6