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TransformationAll matter has the ability to transform,
ie. Change
There are 3 types of transformationsPh i l1. Physical
2. Chemicall3. Nuclear
TransformationsPhysical: does not modify the nature, or the characteristic properties of the matter. The atom and the molecule does not changethe molecule does not change.Chemical: does modify the nature and the characteristic properties of the matter implies a characteristic properties of the matter, implies a rearrangement of the connections between atoms and the formation of new molecules. Nuclear: implies a rearrangement of particles in the nucleus and the formation of new elements
Chemical TransformationThe bonds between the atoms (reactants) will break and new bonds will form elsewhere ( products).H i h i l f iHow to recognize a chemical transformation?
Chemical TransformationThe bonds between the atoms (reactants) will break and new bonds will form elsewhere ( products).H i h i l f iHow to recognize a chemical transformation?
Emission of gas
Chemical TransformationThe bonds between the atoms (reactants) will break and new bonds will form elsewhere ( products).H i h i l f iHow to recognize a chemical transformation?
Emission of gasEmission or absorption of heatEmission or absorption of heat
Chemical TransformationThe bonds between the atoms (reactants) will break and new bonds will form elsewhere ( products).H i h i l f iHow to recognize a chemical transformation?
Emission of gasEmission or absorption of heatEmission or absorption of heatEmission of light
Chemical TransformationThe bonds between the atoms (reactants) will break and new bonds will form elsewhere ( products).H i h i l f iHow to recognize a chemical transformation?
Emission of gasEmission or absorption of heatEmission or absorption of heatEmission of lightColor changeColor change
Chemical TransformationThe bonds between the atoms (reactants) will break and new bonds will form elsewhere ( products).How to recognize a chemical transformation?How to recognize a chemical transformation?
Emission of gasEmission or absorption of heatpEmission of lightColor changeF ti f i it tiFormation of a precipitation
InterpretationCH4 (g) + 2 O2 (g) CO2 (g) + 2 H2O (l)This means:
Methane reacts with oxygen to form carbon dioxide and water
S mbol Ph sical StateSymbol Physical States solidl liquidl liquidg gasaq aqueousaq aqueous
Conservation of MassThink back…Nothing created, nothing lost, all is constant
The law of conservation of mass: the total mass of the i l h l f h dreactants is equal to the total mass of the products
Balancing EquationsWhen we write chemical equations we must balance, according to the law of conservation of massTh f k h l f h f i f Therefore take the example of the formation of ammonia
N + H NHN2(g) + H2(g) NH3(g)
Count the atoms
Unbalanced vs BalancedN2(g) + H2(g) NH3(g)
2 Nitrogen + 2 Hydrogen 1 Nitrogen 3 HydrogenN2(g) + H2(g) 2 NH3(g)
2 Nitrogen + 2 Hydrogen 2 Nitrogen 6 HydrogenN H NHN2(g) + 3 H2(g) 2 NH3(g)
2 Nitrogen + 6 Hydrogen 2 Nitrogen 6 Hydrogen
Unbalanced vs BalancedCH4(g) + O2(g) CO2(g) + H2O
1 Carbon + 4 Hydrogen + 2 Oxygen 1 Carbon 2 Oxygen + 2 Hydrogen 1 Oxygen
CH ( ) + O ( ) CO ( ) + 2 H OCH4(g) + O2(g) CO2(g) + 2 H2O1 Carbon + 4 Hydrogen + 2 Oxygen 1 Carbon 2 Oxygen + 4 Hydrogen 2 Oxygen
CH4(g) + 2 O2(g) CO2(g) + 2 H2O1 Carbon + 4 Hydrogen + 4 Oxygen 1 Carbon 2 Oxygen + 4 Hydrogen 2 Oxygen
PhotosynthesisCO2 (g) + H2O (l) C6H12O6 (s) + O2 (g)
What is the balanced equation?
6CO2 (g) + 6H2O (l) C6H12O6 (s) + 6O2 (g)
Acid‐Base NeutralizationThis is a reaction where an acid and a base react to form the products salt and waterA id B S l WAcid + Base Salt + WaterAcid H+
B OHBase OH‐
HCl + NaOH NaCl + H2O
Acid‐BaseExamples:1. HF + KOH KF + H2O2. H2SO4 + Mg(OH)2 MgSO4 (s) + H2O3. HBr + Ca(OH)2 CaBr2 (s) + H2O
Properties of Matterp
OBJECTIVES:J
Define physical property, and li t l h i l list several common physical properties of substances.p p
MatterMatter is anything that: a) has mass, and b) takes up space) p pMass = a measure of the amount of “stuff” (or material) the object contains stuff (or material) the object contains (don’t confuse this with weight, a
f i )measure of gravity)Volume = a measure of the space poccupied by the object
Describing MatterP ti d t d ib tt b Properties used to describe matter can be classified as:1) Extensive – depends on the amount of
matter in the sample‐Mass, volume, calories are examples
2) Intensive – depends on the type of matter, p ypnot the amount present‐ Hardness, Density, Boiling Point, y, g
Properties are…W d h d ib ( dj i )Words that describe matter (adjectives)Physical Properties‐ a property that can be observed and measured without changing the observed and measured without changing the material’s composition.Examples‐ color hardness m p b pExamples‐ color, hardness, m.p., b.p.Chemical Properties‐ a property that can only be observed by changing the composition of be observed by changing the composition of the material. Examples‐ ability to burn, decompose, p y , p ,ferment, react with, etc.
States of matter1) Solid‐matter that can not flow (definite shape) and
has definite volume.2) Liquid definite volume but takes the shape of its 2) Liquid‐ definite volume but takes the shape of its
container (flows).3) Gas‐ a substance without definite volume or shape 3) Gas a substance without definite volume or shape
and can flow.Vapor‐ a substance that is currently a gas, but normally is a liquid or solid at room temperature. (Which is correct: “water gas”, or “water vapor”?)
States of MatterStates of MatterDefinite Definite Result of a
TemperatureI Will it
Volume? Shape?TemperatureIncrease?
Small
Compress?
Solid YES YES Small Expans. NO
Liquid YES NO Small Expans. NO
Gas NO NO Large YESGas NO NO Expans. YES
4th state: Plasma formed at high4th state: Plasma - formed at high temperatures; ionized phase of matter as found in the sun
Physical vs. Chemical Changeh l h ll h h blPhysical change will change the visible
appearance, without changing the composition f th t i lof the material.Boil, melt, cut, bend, split, crackb l d llIs boiled water still water?
Can be reversible, or irreversibleChemical change ‐ a change where a new form of matter is formed.
Rust, burn, decompose, ferment
MixturesOBJECTIVES:
Distinguish between homogeneous and heterogeneous homogeneous and heterogeneous samples of matter.
Mixturestu esOBJECTIVES:
Describe two ways that components of mixtures can be components of mixtures can be separated.
Mixtures are a physical blend of at least b h i bl i i two substances; have variable composition.
They can be either:) H t th i t i t 1) Heterogeneous – the mixture is not
uniform in compositionCh l t hi ki l il• Chocolate chip cookie, gravel, soil.
2) Homogeneous ‐ same composition th h t ll d “ l ti ”throughout; called solutions• Kool‐aid, air, salt waterE k i ’ iEvery part keeps it’s own properties.
Solutions are homogeneous mixtures
Mixed molecule by molecule, thus too small to see the different partsCan occur between any state of matter: gas y gin gas; liquid in gas; gas in liquid; solid in liquid; solid in solid (alloys), etc.q ; ( y ),Thus, based on the distribution of their components mixtures are called components, mixtures are called homogeneous or heterogeneous.
Phase?The term “phase” is used to describe any part of a sample with uniform composition p p pof properties.A homogeneous mixture consists of a singleA homogeneous mixture consists of a singlephaseA heterogeneous mixture consists of two or A heterogeneous mixture consists of two or more phases.
Separating Mixtures
Some can be separated easily by physical means: rocks and marbles, iron filings and sulfur (use magnet) gDifferences in physical properties can be used to separate mixturesused to separate mixtures.Filtration ‐ separates a solid from the li id i h t i t (b liquid in a heterogeneous mixture (by size)
Separation of a MixtureSeparation of a MixtureComponents of dyes such as ink may be separated by paper chromatographyseparated by paper chromatography.
Separation of a MixtureDistillation: takes advantageDistillation: takes advantage of different boiling points.
NaCl boils at 1415 oC
Elements and Compoundsp
OBJECTIVES:J
Explain the differences between l t d dan element and a compound.
Elements and CompoundsElements and CompoundsOBJECTIVES:
Identify the chemical symbols of elements and name elements elements, and name elements given their symbols.
Substances: element or compound
Elements‐ simplest kind of mattercannot be broken down any simpler and still have
i f h l !properties of that element!all one kind of atom.
Compounds are substances that can be broken down Compounds are substances that can be broken down only by chemical methods
when broken down, the pieces have completely different p p yproperties than the original compound.made of two or more atoms, chemically combined (not just a physical blend!)just a physical blend!)
Compound vs. MixtureCompound MixtureCompound Mixture
Made of one kind Made of more thanof material one kind of material
Made by a Made by aMade by a chemical change
Made by a physical change
Definitecomposition
Variablecompositioncomposition composition
Elements vs. CompoundsElements vs. Compounds
Compounds can be broken down into Compounds can be broken down into simpler substances by chemical means, b t l t cannotbut elements cannot.A “chemical change” is a change that produces matter with a different composition than the original matter.p g
Chemical ChangeA h i hi h b tA change in which one or more substances are converted into different substances.
Heat and lightlight are often
id fevidence of a chemical hchange.
Properties of CompoundsProperties of CompoundsQuite different properties than their component elementscomponent elements.Due to a CHEMICAL CHANGE, the resulting compound has new and different properties:compound has new and different properties:• Table sugar – carbon, hydrogen, oxygen• Sodium chloride sodium chlorine• Sodium chloride – sodium, chlorine• Water – hydrogen, oxygen
Symbols & Formulasl h lCurrently, there are 117 elements
Elements have a 1 or two letter symbol, and d h f lcompounds have a formula.
An element’s first letter always capitalized; if there is a second letter it is written lowercase: B Ba C Ca H second letter, it is written lowercase: B, Ba, C, Ca, H, He
Chemical ReactionsChemical ReactionsOBJECTIVES:J
Identify four possible clues that h i l h h t k a chemical change has taken place.p
Chemical Reactions
OBJECTIVES:J
Apply the law of conservation of t h i l timass to chemical reactions.
Chemical ChangesChemical ChangesThe ability of a substance to undergo a specific chemical change is called a chemical specific chemical change is called a chemical property.• iron plus oxygen forms rust so the ability to • iron plus oxygen forms rust, so the ability to rust is a chemical property of iron
During a chemical change (also called During a chemical change (also called chemical reaction), the composition of matter always changes matter always changes.
Chemical Reactions are…When one or more substances are changed into new substances.Reactants‐ the stuff you start withProducts‐ what you makeProducts what you makeThe products will have NEW PROPERTIES different from the reactants you started withdifferent from the reactants you started withArrow points from the reactants to the new
d tproducts
Recognizing Chemical Changes1) Energy is absorbed or released (temperature
changes hotter or colder)2) Color changes3) Gas production (bubbling, fizzing, or odor
h k )change; smoke)4) formation of a precipitate ‐ a solid that separates
from solution (won’t dissolve)from solution (won t dissolve)5) Irreversibility ‐ not easily reversedBut there are examples of these that are not chemical But, there are examples of these that are not chemical
– boiling water bubbles, etc.
Conservation of Mass D i h i l i h f During any chemical reaction, the mass of the products is always equal to the mass of h the reactants.All the mass can be accounted for:Burning of wood results in products that appear to have less mass as ashes; where is the rest?
Law of conservation of massLaw of conservation of mass