Chy Ch3
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Chapter 3: Matter
Chapter Outline • Describing matter – Physical states of matter – Physical and chemical properties – Composition • Pure substances - Elements and compounds • Mixtures - Homogeneous and heterogeneous
• Separating matter based upon differences in physical properties – Filtration and distillation
Physical States of Matter • States of matter: – Solid – Liquid – Gas – Plasma (not covered)
Physical States of Matter • A substance’s state of matter is related to the strength of the attractive forces among the matter’s particles – E.g. solids have very strong attractive forces between particles and gases very weak forces
Solids • Shape – fixed/definite
• Volume – fixed – Varies slightly with temperature
• Particles are closely packed, rigidly arranged, and strongly attracted to each other
Liquids • Shape – A liquid takes the shape of the bottom of the container up to the volume it fills
• Volume – fixed/definite – Varies slightly with temperature
• Particles are sliding over each other and moderately attracted to each other
Gases • Shape and Volume – A gas takes the shape and volume of a closed container • Gases expand or compress to fill a closed container
• Gas particles are far apart, moving very rapidly as they bounce off each other and the walls of the container – Gas particles are very weakly attracted to each other
Change of State • Increasing the temperature of a substance increases the kinetic energy of its particles – Kinetic energy = energy of motion – A change of state occurs when the energy of the particles is greater than the forces that hold the particles together at a given state
Properties of Matter • Physical property – characteristic of a substance that can be determined without changing the chemical composition of the substance – Examples:
Properties of Matter • Chemical property – ability of a substance to form new substances – Always involves a change in chemical composition of the substance – Examples:
Related Terms • Physical change – Change in a substance’s physical properties without a change in chemical composition – Examples:
Related Terms • Chemical change – Change in a substance’s chemical composition – Also called a chemical reaction
Practice • Groups answer # 17 on page 67.
Composition of Matter • Pure Substance - matter with definite composition – Elements and compounds are pure substances
• Mixture – matter with variable composition
Pure Substances • Elements – substance that cannot be broken down into other substances by chemical means – Examples: see periodic table
Pure Substances • Compounds – 2 or more (different) elements joined in a definite ratio – Compounds can be broken down into elements by chemical means – Examples:
Pure Substances • The properties of compounds are different from those of the elements it contains. – Example:
Mixtures • Mixture – matter with variable composition – 2 or more pure substances mixed together – The components of a mixture are not joined to each other in any fixed ratio • example
Mixtures • Homogeneous mixture – Mixture with the same properties throughout • Also called a solution
– Examples:
• Heterogeneous mixture – Mixture with regions that have different properties – Examples:
Summary • See Board.
Separating Mixtures • Most matter in the world is a mixture • To separate the components of a mixture, chemists take advantage of differences in the physical properties of the mixture’s components. – Not always easy!
Separating Mixtures • Filtration – Used to separate a solid from a liquid in a heterogeneous mixture
Separating Mixtures • Can filtration be used to separate sugar from water in sugar water? – Why or why not?
Separating Mixtures • Distillation – Separates mixtures based upon differences in volatility • Volatility = • Volatility is related to a substance’s boiling point – A highly volatile substance will have a _______ boiling points.
Distillation • Distillation works best when there is at least a 100 C difference in boiling points. • Consider a mixture of water and ethanol. – Boiling point water ____________ – Boiling point ethanol ______________
Distillation Apparatus
Distillation • Heat the mixture to the b.p. of the substance with the lower b.p. – Change of state occurs • Ethanol becomes a gas • Ethanol vapors expand to fill the distillation apparatus
Distillation • Ethanol gas enters the water cooled condensing tube – Change of state occurs as the ethanol is cooled below __________ • Ethanol gas condenses and forms a liquid • Ethanol liquid drips into the collecting container
Distillation • Temperature shoots up to the bp of water – Change of state occurs • Water becomes a gas
– Water vapors expand to fill the distillation apparatus – Water vapors enter the condensing tube – Water condenses to form a liquid……
Chapter Outline • Describing matter – Physical states of matter – Physical and chemical properties – Composition • Pure substances - Elements and compounds • Mixtures - Homogeneous and heterogeneous
• Separating matter based upon differences in physical properties – Filtration and distillation
Physical States of Matter • States of matter: – Solid – Liquid – Gas – Plasma (not covered)
Physical States of Matter • A substance’s state of matter is related to the strength of the attractive forces among the matter’s particles – E.g. solids have very strong attractive forces between particles and gases very weak forces
Solids • Shape – fixed/definite
• Volume – fixed – Varies slightly with temperature
• Particles are closely packed, rigidly arranged, and strongly attracted to each other
Liquids • Shape – A liquid takes the shape of the bottom of the container up to the volume it fills
• Volume – fixed/definite – Varies slightly with temperature
• Particles are sliding over each other and moderately attracted to each other
Gases • Shape and Volume – A gas takes the shape and volume of a closed container • Gases expand or compress to fill a closed container
• Gas particles are far apart, moving very rapidly as they bounce off each other and the walls of the container – Gas particles are very weakly attracted to each other
Change of State • Increasing the temperature of a substance increases the kinetic energy of its particles – Kinetic energy = energy of motion – A change of state occurs when the energy of the particles is greater than the forces that hold the particles together at a given state
Properties of Matter • Physical property – characteristic of a substance that can be determined without changing the chemical composition of the substance – Examples:
Properties of Matter • Chemical property – ability of a substance to form new substances – Always involves a change in chemical composition of the substance – Examples:
Related Terms • Physical change – Change in a substance’s physical properties without a change in chemical composition – Examples:
Related Terms • Chemical change – Change in a substance’s chemical composition – Also called a chemical reaction
Practice • Groups answer # 17 on page 67.
Composition of Matter • Pure Substance - matter with definite composition – Elements and compounds are pure substances
• Mixture – matter with variable composition
Pure Substances • Elements – substance that cannot be broken down into other substances by chemical means – Examples: see periodic table
Pure Substances • Compounds – 2 or more (different) elements joined in a definite ratio – Compounds can be broken down into elements by chemical means – Examples:
Pure Substances • The properties of compounds are different from those of the elements it contains. – Example:
Mixtures • Mixture – matter with variable composition – 2 or more pure substances mixed together – The components of a mixture are not joined to each other in any fixed ratio • example
Mixtures • Homogeneous mixture – Mixture with the same properties throughout • Also called a solution
– Examples:
• Heterogeneous mixture – Mixture with regions that have different properties – Examples:
Summary • See Board.
Separating Mixtures • Most matter in the world is a mixture • To separate the components of a mixture, chemists take advantage of differences in the physical properties of the mixture’s components. – Not always easy!
Separating Mixtures • Filtration – Used to separate a solid from a liquid in a heterogeneous mixture
Separating Mixtures • Can filtration be used to separate sugar from water in sugar water? – Why or why not?
Separating Mixtures • Distillation – Separates mixtures based upon differences in volatility • Volatility = • Volatility is related to a substance’s boiling point – A highly volatile substance will have a _______ boiling points.
Distillation • Distillation works best when there is at least a 100 C difference in boiling points. • Consider a mixture of water and ethanol. – Boiling point water ____________ – Boiling point ethanol ______________
Distillation Apparatus
Distillation • Heat the mixture to the b.p. of the substance with the lower b.p. – Change of state occurs • Ethanol becomes a gas • Ethanol vapors expand to fill the distillation apparatus
Distillation • Ethanol gas enters the water cooled condensing tube – Change of state occurs as the ethanol is cooled below __________ • Ethanol gas condenses and forms a liquid • Ethanol liquid drips into the collecting container
Distillation • Temperature shoots up to the bp of water – Change of state occurs • Water becomes a gas
– Water vapors expand to fill the distillation apparatus – Water vapors enter the condensing tube – Water condenses to form a liquid……
