what defines the matter around us?. leq: what forms does matter take?
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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
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