CHAPTER 1:
Matter
● Matter - has mass and takes up space
● Mass - quantity of matter in any object
● Chemistry - the study of the composition, structure, and properties of matter + of the
energy consumed or given off when matter undergoes a change
● Pure Substances - cannot be decomposed into other substances by ordinary means
○ Atom- smallest particle of an element
○ Element - a pure substance that can’t be broken down into simpler substances
■ Can combine to form compounds
○ Compound - pure substance made of 2+ elements linked together
■ Fixed proportions
■ Can be broken down into those elements by chemical process
○ Molecule - collection of atoms chemically bonded together in specific proportions
■ Smallest representative unit of a compound
■ Some elements also exist as molecules
● Diatomics: O2, H2, Cl2, Br2, F2
● Chemical Bond - a force that holds 2 atoms or ions in a compound together
● Physical Process - a transformation of a sample of matter that doesn’t change the
chemical identity of any substance in the sample.
● Chemical Reaction - the transformation of 1+ substances into different substances.
● Difference between compounds and molecules = molecules are typically nonmetal while
compounds typically contain metal
Ways to Represent Molecules:
,Mixtures
● Mixture - 2+ pure substances combined physically
● Individual substances retain their chemical identities and can be separated by a physical
process
● Homogeneous Mixture - the substances are distributed uniformly throughout. There are
no visible regions/boundaries
○ Also called solutions
○ Ie: coffee, sugar water
● Heterogeneous Mixture - the components are not distributed uniformly. There are
distinct regions of different compositions
○ Ie: salad dressing - can see the oil and water layers, salad
Separating Mixtures: a physical process
● Ex: Evaporation, filtration, decanting,
● Chemical formula - notation for representing elements and compounds --- H2O
● Chemical Equation - expresses the substances (and amount) involved in a chem reaction
● Energy - the capacity to do work
● Law of Constant Composition - all samples of a particular compound contain the same
elements combined in the same proportions
● Ion - a particle consisting of one or more atoms that has a net positive or negative charge
○ Cation - an ion with a positive charge
○ Anion - an ion with a negative charge
Properties of Matter
● Physical properties - a property of a substance that can be observed without changing it
into another substance
○ ex/ color, solid/liquid/gas, density, melting point
● Density (d) - the ratio of the mass (m) of an object to its volume (V)
○ d = m/V
● Chemical Property - a property of a substance that can be observed only by reacting it to
form another substance
, ○ Changing a substance
■ Process of change = chemical reaction
● Intensive Properties - a property that is independent of the amount of substance present
○ Ie: dull, brittle, burn, color, density
● Extensive Properties - a property that varies with the quantity of the substance present
○ Ie: mass, shape
States of matter
● Solid - particles in fixed pattern but vibrate
○ Definite shape and volume
● Liquid - Particles are close together but arranged randomly and free to move
○ Definite volume, shape of container
● Gas - Particles are far apart, move at high speeds
○ No definite shape nor volume
Changing States
● Sublimation - transformation of a solid directly into a vapor (gas)
● Deposition - transformation of a vapor directly into a solid
● Vaporization - liquid → gas
● Condensation - gas → liquid
● Melting - solid → liquid
● Freezing - Liquid → solid
Scientific Method
→ an approach to acquiring knowledge based on observation of phenomena, development of a
testable hypothesis, and additional experiments that test the validity of the hypothesis
● Hypothesis - a tentative + testable explanation for an observation
● Scientific Theory (model) - a general explanation of a widely observed phenomenon that
has been extensively tested and validated
, 8/25 Significant Figures:
→ Why SF? Answer: Uncertainty in Scientific Measurements:
○ Systematic errors - ex a faulty scale that’s always off by 1 pound
○ Random errors - limitation due to tools or experimenter
○ Accuracy
○ Precision
Sig Figs
● Tells you the certainty in a measured value
● Rules:
○ All non-zero digits are significant
■ 123 = 3 SF
■ 123.1 = 4 SF
○ Leading zeroes are not significant
■ .000012 = 2 sig figs
○ Middle zeroes are significant
■ 705.01 = 5 SF
○ Trailing zeroes = depends
■ If there is a decimal point, they are significant
● 200. = 3 SF
● .00520 = 3 SF
■ If no decimal point, trailing zeros are NOT significant
● 200 = 1 SF
○ Exact numbers (12 items/a dozen, counting numbers - like # of people in room)
have an infinite number of significant figures
Matter
● Matter - has mass and takes up space
● Mass - quantity of matter in any object
● Chemistry - the study of the composition, structure, and properties of matter + of the
energy consumed or given off when matter undergoes a change
● Pure Substances - cannot be decomposed into other substances by ordinary means
○ Atom- smallest particle of an element
○ Element - a pure substance that can’t be broken down into simpler substances
■ Can combine to form compounds
○ Compound - pure substance made of 2+ elements linked together
■ Fixed proportions
■ Can be broken down into those elements by chemical process
○ Molecule - collection of atoms chemically bonded together in specific proportions
■ Smallest representative unit of a compound
■ Some elements also exist as molecules
● Diatomics: O2, H2, Cl2, Br2, F2
● Chemical Bond - a force that holds 2 atoms or ions in a compound together
● Physical Process - a transformation of a sample of matter that doesn’t change the
chemical identity of any substance in the sample.
● Chemical Reaction - the transformation of 1+ substances into different substances.
● Difference between compounds and molecules = molecules are typically nonmetal while
compounds typically contain metal
Ways to Represent Molecules:
,Mixtures
● Mixture - 2+ pure substances combined physically
● Individual substances retain their chemical identities and can be separated by a physical
process
● Homogeneous Mixture - the substances are distributed uniformly throughout. There are
no visible regions/boundaries
○ Also called solutions
○ Ie: coffee, sugar water
● Heterogeneous Mixture - the components are not distributed uniformly. There are
distinct regions of different compositions
○ Ie: salad dressing - can see the oil and water layers, salad
Separating Mixtures: a physical process
● Ex: Evaporation, filtration, decanting,
● Chemical formula - notation for representing elements and compounds --- H2O
● Chemical Equation - expresses the substances (and amount) involved in a chem reaction
● Energy - the capacity to do work
● Law of Constant Composition - all samples of a particular compound contain the same
elements combined in the same proportions
● Ion - a particle consisting of one or more atoms that has a net positive or negative charge
○ Cation - an ion with a positive charge
○ Anion - an ion with a negative charge
Properties of Matter
● Physical properties - a property of a substance that can be observed without changing it
into another substance
○ ex/ color, solid/liquid/gas, density, melting point
● Density (d) - the ratio of the mass (m) of an object to its volume (V)
○ d = m/V
● Chemical Property - a property of a substance that can be observed only by reacting it to
form another substance
, ○ Changing a substance
■ Process of change = chemical reaction
● Intensive Properties - a property that is independent of the amount of substance present
○ Ie: dull, brittle, burn, color, density
● Extensive Properties - a property that varies with the quantity of the substance present
○ Ie: mass, shape
States of matter
● Solid - particles in fixed pattern but vibrate
○ Definite shape and volume
● Liquid - Particles are close together but arranged randomly and free to move
○ Definite volume, shape of container
● Gas - Particles are far apart, move at high speeds
○ No definite shape nor volume
Changing States
● Sublimation - transformation of a solid directly into a vapor (gas)
● Deposition - transformation of a vapor directly into a solid
● Vaporization - liquid → gas
● Condensation - gas → liquid
● Melting - solid → liquid
● Freezing - Liquid → solid
Scientific Method
→ an approach to acquiring knowledge based on observation of phenomena, development of a
testable hypothesis, and additional experiments that test the validity of the hypothesis
● Hypothesis - a tentative + testable explanation for an observation
● Scientific Theory (model) - a general explanation of a widely observed phenomenon that
has been extensively tested and validated
, 8/25 Significant Figures:
→ Why SF? Answer: Uncertainty in Scientific Measurements:
○ Systematic errors - ex a faulty scale that’s always off by 1 pound
○ Random errors - limitation due to tools or experimenter
○ Accuracy
○ Precision
Sig Figs
● Tells you the certainty in a measured value
● Rules:
○ All non-zero digits are significant
■ 123 = 3 SF
■ 123.1 = 4 SF
○ Leading zeroes are not significant
■ .000012 = 2 sig figs
○ Middle zeroes are significant
■ 705.01 = 5 SF
○ Trailing zeroes = depends
■ If there is a decimal point, they are significant
● 200. = 3 SF
● .00520 = 3 SF
■ If no decimal point, trailing zeros are NOT significant
● 200 = 1 SF
○ Exact numbers (12 items/a dozen, counting numbers - like # of people in room)
have an infinite number of significant figures
