Matter & Energy Chapter 3

Universe

Matter

Universe Classified Matter is the part of the universe that has mass and volume Energy is the part of the universe that has the ability to do work Chemistry is the study of matter –The properties of different types of matter –The way matter behaves when influenced by other matter and/or energy

THREE STATES OF MATTER Solid -- has definite shape and definite volume ( stone, gold ring, NaCl crystal) Liquid -- has definite volume but no definite shape ( water, alcohol, blood, gasoline) Gas -- neither definite shape nor definite volume (air, helium, oxygen)

solid, liquid, gas States of Matter

Figure 3.1: Liquid water takes the shape of its container

THREE STATES OF MATTER

Figure 3.11: In ice, the water molecules vibrate randomly about their positions in the solid

STATE OF MATTER DEPENDS UPON: Strength of the forces between the particles in the sample of matter (Stronger forces favor solids.) Conditions under which the sample exists -- the temperature and pressure (Lower temperatures and higher pressures favor solids.)

Properties Characteristics of the substance under observation Properties can be either ¬directly observable or ­the manner something interacts with other substances in the universe

PHYSICAL PROPERTY - characteristic of a substance that can change without the substance becoming a different substance. Physical properties include: –color-density –odor- melting point –volume- boiling point –state (solid, liquid, gas)

CHEMICAL PROPERTY - the ability of a substance to change to a different substance. Chemical properties include the ability to: –react with acids –burn (combine with oxygen) –corrode or rust –sour or spoil –to ferment

Classify Each of the following as Physical or Chemical Properties ¬The boiling point of ethyl alcohol is 78°C. ­Diamond is very hard. ®Sugar ferments to form ethyl alcohol.

Classify Each of the following as Physical or Chemical Properties ¬The boiling point of ethyl alcohol is 78°C. –Physical property – describes inherent characteristic of alcohol – boiling point ­Diamond is very hard. –Physical property – describes inherent characteristic of diamond – hardness ®Sugar ferments to form ethyl alcohol. –Chemical property – describes behavior of sugar – forming a new substance (ethyl alcohol)

PHYSICAL CHANGE -change in the form, size, shape, or state of a substance, but not its chemical nature; no chemical bonds are broken. Physical changes include: –melting- crushing –freezing- grinding –boiling- dissolving –evaporating- breaking

Figure 3.7: No chemical change occurs when salt water is distilled

CHEMICAL CHANGE - the formation of new substance(s) with new properties through the reorganization of atoms -- a chemical reaction. Chemical changes include: –corroding- burning –rusting- rotting –souring- reacting with acids –fermenting- reacting with water

IS ELECTROLYSIS A CHEMICAL OR PHYSICAL CHANGE? Chemical

Classify Each of the following as Physical or Chemical Changes ¬Iron metal is melted. ­Iron combines with oxygen to form rust. ®Sugar ferments to form ethyl alcohol.

Classify Each of the following as Physical or Chemical Changes ¬Iron is melted. –Physical change – describes a state change, but the material is still iron ­Iron combines with oxygen to form rust.. –Chemical change – describes how iron and oxygen react to make a new substance, rust ®Sugar ferments to form ethyl alcohol. –Chemical change – describes how sugar forms a new substance (ethyl alcohol)

Universe Matter Energy

Matter Homogeneous Heterogeneous Pure Substance Solution Physical Change Mixture

Universe Matter Energy Homogeneous Physical Change Heterogeneous Pure Substance Solution Mixture

Pure Substance Element Compound

ELEMENT - a substance that cannot be decomposed into simpler substances by chemical or physical means. Elements include: –oxygen - iron –silver- aluminum –carbon- nitrogen –gold- neon

PERIODIC TABLE OF THE ELEMENTS

COMPOUND - a substance with constant composition that can be broken into elements by chemical processes. Compounds include: –water- sodium chloride –ethanol- ammonia –sugar- carbon dioxide –potassium nitrate- sodium hydroxide

Universe Matter Energy Homogeneous Physical Change Heterogeneous Pure Substance Solution Mixture Element Compound Chemical Change

HETEROGENEOUS MATTER - has different properties throughout -- a mixture. –Salt and pepper –soil –granite –sea water –spaghetti & meat balls

Pure Substances vs. Mixtures Pure Substances –All samples have the same physical and chemical properties –Constant Composition  all samples have the same composition –Homogeneous –Separate into components based on chemical properties All mixtures are made of pure substances

Pure Substances vs. Mixtures Mixtures –Different samples may show different properties –Variable composition –Homogeneous or Heterogeneous –Separate into components based on physical properties All mixtures are made of pure substances

Figure 3.5: Sand and water do not mix to form a uniform mixture

SEPARATION OF MIXTURES - mixtures can be separated by physical means. –distillation –filtration –centrifuging –magnet –evaporation –chromatography

Separation of Mixtures Separate mixtures based on different physical properties of the components –Physical change EvaporationVolatility ChromatographyAdherence to a Surface FiltrationState of Matter (solid/liquid/gas) DistillationBoiling Point TechniqueDifferent Physical Property

Figure 3.6: Distillation of a solution consisting of salt dissolved in water

Figure 3.8: Filtration separates a liquid from a solid

CENTRIFUGE

Pure Substance Element Compound Electron Shells Nucleus Chemical Change

HOMOGENEOUS MATTER - a substance with the same properties throughout -- a pure substance. Elements and compounds are pure substances (homogeneous matter).

SOLUTION - is a homogeneous mixture. - has a variable composition... - can be separated by physical means. - no evidence of a chemical change when a solution is formed.

Figure 3.9: Separation of a sand-saltwater mixture

Identity Each of the following as a Pure Substance, Homogeneous Mixture or Heterogeneous Mixture ¬Gasoline ­A stream with gravel on the bottom ®Copper metal

Identity Each of the following as a Pure Substance, Homogeneous Mixture or Heterogeneous Mixture ¬Gasoline –a homogenous mixture ­A stream with gravel on the bottom –a heterogeneous mixture ®Copper metal –A pure substance (all elements are pure substances)

Universe Matter Energy Homogeneous Physical Change Heterogeneous Pure Substance Solution Mixture Element Compound Chemical Change Electron Levels Nucleus

Pure Substance Element Compound Electron Shells Nucleus Chemical Change Electrons Protons Neutrons

Universe Matter Energy Homogeneous Physical Change Heterogeneous Pure Substance SolutionMixture ElementCompound Chemical Change Electron Levels Nucleus Electrons Protons Neutrons

Energy Potential Energy Potential Energy Kinetic Energy Kinetic Energy

Universe Matter Energy Homogeneous Physical Change Heterogeneous Pure Substance SolutionMixture ElementCompound Chemical Change Electron Levels Nucleus Electrons ProtonsNeutrons Potential Energy Kinetic Energy

Potential Energy Position Composition

Universe Matter Energy Homogeneous Physical Change Heterogeneous Pure Substance SolutionMixture ElementCompound Chemical Change Electron Levels Nucleus Electrons ProtonsNeutrons Potential Energy Kinetic Energy Position Composition

Position Gravitational Electrostatic

Universe Matter Energy Homogeneous Physical Change Heterogeneous Pure Substance SolutionMixture ElementCompound Chemical Change Electron Levels Nucleus Electrons ProtonsNeutrons Potential Energy Kinetic Energy Position Composition Gravitational Electrostatic

Composition Nuclear Chemical

Energy and Energy Changes Capacity to do work –chemical, mechanical, thermal, electrical, radiant, sound, nuclear Energy may affect matter –e.g. raise its temperature, eventually causing a state change –All physical changes and chemical changes involve energy changes

Energy and the Temperature of Matter The amount the temperature of an object increases depends on the amount of heat added (Q). –If you double the added heat energy the temperature will increase twice as much. The amount the temperature of an object increases depends on its mass –If you double the mass it will take twice as much heat energy to raise the temperature the same amount.

Units of Energy One calorie is the amount of energy needed to raise the temperature of one gram of water by 1°C kcal = energy needed to raise the temperature of 1000 g of water 1°C joule J = 1 cal4.184 kJ = 1 kcal In nutrition, calories are capitalized 1 Cal = 1 kcal

Converting Calories to Joules Convert 60.1 cal to joules

Specific Heat Capacity Specific Heat (s) is the amount of energy required to raise the temperature of one gram of a substance by one Celsius degree Specific heat is a characteristic or identifying property of matter.

ENERGY CALCULATIONS Heat (Q) -- J mass (m) -- g specific heat (s) -- J/gC o “change” in temperature (  t) -- C o Q = m s  t

Calculate the amount of heat energy (in joules) needed to raise the temperature of 7.40 g of water from 29.0°C to 46.0°C

A 1.6 g sample of metal that appears to be gold requires 5.8 J to raise the temperature from 23°C to 41°C. Is the metal pure gold? Table 3.2 lists the specific heat of gold as 0.13 Therefore the metal cannot be pure gold.

Universe Matter Energy Homogeneous Physical Change Heterogeneous Pure Substance SolutionMixture ElementCompound Chemical Change Electron Levels Nucleus Electrons ProtonsNeutrons Potential Energy Kinetic Energy Position Composition GravitationalElectrostatic Nuclear Chemical Nuclear Change Chemical Change

“TO BUILD FROM MATTER IS SUBLIMELY GREAT, BUT GODS AND POETS ONLY CAN CREATE.” Pitt