Ch 1 Flashcards
Chemistry is the study of the
Composition, structure, and properties of matter, the processes that matter undergoes, and the energy changes that accompany these processes
Instruments are routinely used in chemistry to
Extend our ability to observe and make measurements
Instruments make it possible to look at
Micro structures
Micro structures
Things too tiny to be seen with the unaided eye
The scanning electron microscope reveals
Tiny structures by beaming electrons at them
X rays can also be used to
Determine micro structures
X Ray diffraction pattern can be analyzed to
Reveal the arrangement of atoms, molecules, or other particles that make up the materials
By learning about micro structures chemists can
Explain the behavior of macrostructures
Organic chemistry
The study of most carbon containing compounds
Inorganic chemistry
The study of non organic substances, many of which have organic fragments bonded to metals (organometallics)
Physical chemistry
The study of the properties and changes of matter and their relation to energy
Analytical chemistry
The identification of the components and composition of materials
Because we now know that both living and non living matter consists of chrmical structures
Chemistry is central to all the sciences
Biochemistry
The study of substances and processes occurring in living things
Theoretical chemistry
The use of math and computers to understand the principles behind observed chemical behavior and to design and predict the properties of new compounds
A chemical is any substance that has a
Definite composition
Knowing the properties of chemicals allows chemists to
Find suitable uses for them
Basic research is carried out for the sake of
Increasing knowledge, such as how and why a specific reaction occurs and what the properties of a substance are
Basic research can result in
Chance discoveries
Applied research is generally carried out to
Solve a problem
In applied research researchers are driven not by curiosity or a desire to know but by a
Desire to solve a specific problem
Technological development typically involves
The production and use of products that improve our quality of life
Technological applications often
Lag far behind the discoveries that are eventually used in technologies
Basic research applied research and technological development often
Overlap.
Discoveries made in basic research may lead to
Applications that can result in new technologies
Explaining what matter is involved
Finding properties that all matter has in common
Volume is the amount of
Three dimensional space an object occupies. All matter has volume
Mass is a measure of
The amount of matter. All matter has mass. Mass is the measurement you make using a balance.
Volume and mass are the
General properties of all matter
The fundamental building blocks of matter are
Atoms and molecules
Atoms and molecules make up
Elements and compounds
An atom is
The smallest unit of an element that maintains the chemical identity of that element
An element is a
Pure substance that cannot be broken down into simpler, stable substances and is made of one type of atom
A compound is a substance that
Can be broken down into simple stable substances
Each compound is made from the
Atoms of two or more elements that are chemically bonded
Molecule
The smallest unit of an elect or compound that retains all of the properties or that element or compound
Every substance whether it is an element or a compound has
Characteristic properties
Chemists use properties to
Distinguish between substances and to separate them
A property may be a
Characteristic that defines an entire set of substances
The distinguishing property of metals is that they
Conduct electricity well
Properties can ell reveal the identity of
An unknown substance
Properties are either
Intensive or extensive
Extensive properties depend on
The amount of matter that is present
Examples of extensive properties
Volume mass and amount of energy in a substance
Intensive properties
Do not depend on the amount of matter present
Examples of intensive properties
Melting point
Boiling point
Density
Ability to conduct electricity and to transfer energy as heat
Intensive properties are the same for
A given substance regardless of how much of the substance is present
A physical property is a
Characteristic that can be observed or measures without changing the identity of the substance
Physical properties describe the
Substance itself rather than describing how it can change into other substances
Examples of physical properties
Melting point, boiling point
Physical change
Doesn’t involve a change in the identity of a substance
Examples of physical change
Grinding
Cutting
Melting
Boiling
Change of state is a
Physical change of a substance from one state to another
3 common states of matter
Solid
Liquid
Gas
Matter in the solid state has
Definite volume and definite shape
Solids have definite volume and shape because the particles in them
Are packed together in relatively fixed positions
The particles in solids are held
Close together by the strong attractive forces between them and only vibrate about fixed pts
Matter in the liquid state has a
Definite volume but not a definite shape. A liquid assumes the shape of its container
Liquids have this characteristic because the particles in them are
Close together but can move past one another
Particles in a liquid move more
Rapidly than those in a solid, allowing them to overcome the strong attractive forces and flow
Matter in the gas state has neither
Definite volume not definite shape
All gases have this characteristic because they are compose of particles that
Move very rapidly and are at great distances from one another
At these great distances the attractive forces between has particles have
Less of an effect than they do at small distances (liquids and solids)
Plasma is a
High temperature physical state of matter in which atoms law most of the electrons
A change of state does not affect the
Identity of a substance
A chemical property relates to a substances ability to
Undergo changes that transform it into different substances
Chemical properties are easiest to see when
Substances react to form new substances
A chemical change or reactions is a change in which one or more substances are
Converts into different substances
Substances that react in a chemical change are called
Reactants
Substances that are formed by the chemical change are called
Products
Arrows and plus signs can be substituted for the words
Yields and plus
Chemical changes and reactions form products whose
Properties differ greatly from those of reactants
Chemical changes do not affect the total amount of
Matter present before and after a reaction
When physical or chemical changes occur
Energy is always involved
Although energy can be absorbed or released in a change it is not
Destroyed or created. It simply assumed a different form: law of conservation of energy
Composition of a pure substance is the
Same throughout and does not vary sample to sample
A pure substance can be an
Element or a compound
Mixtures contain more than
One substance and can vary in composition and properties from sample to sample
All matter can be classified in terms of
Uniformity of composition and properties or a given sample
Mixture
A blend of 2 or more kinds of matter each of which retains its own identity and properties
Components of a mixture are
Mixed together physically and can usually be separated
The properties of a mixture are a combination of
The properties of its components
Because mixtures can contain various amounts of different substances
A mixtures composition must be specified in terms o percentage by mass or volume
Homogenous mixtures
Uniform in composition; have the same proportion of components throughout
Homogenous mixtures are also called
Solutions
Heterogenous mixtures
Not uniform throughout
Some mixtures can be separated by
Filtration or vaporized to separate the different components
If the solid in a liquid-solid mixture settled to the bottom of the container the liquid
Can be carefully poured off (decanted)
Centrifuge can be used to
Separate some solid liquid mixtures
Paper chromatography can be used to
Separate mixtures of dyes or pigments because the different substances move at different rates on the papers
Any sample of a pure substance is
Homogenous
Pure substance
Has a fixed composition
Pure substances differ from mixture because
Every sample has exactly the same characteristic properties and composition
A compound can be decomposed into
Two or more simpler compounds or elements by a chemical change
All chemicals have some
Impurities
The purity ranking of chemical grades can vary when
Agencies differ in their standards
Primary standard reagent grade is always purer than the
Technical grade for the and chemical
Chemists need to be aware of the kinds of impurities in a reagent because
Impurities could affect the results of a reaction
Grades or chemical purity from least to greatest
Technical FCC NF CP USP ACS Primary standard reagents
Technical
Industrial chemicals
FCC
Food chemical code specifications
NF
National formulary specifications
CP
Chemically pure; purer than technical grade
USP
United States pharmacopoeia standards
Acs
American chemical society specified reagents
Weight changes with change if
Force of gravity. Mass remains the same
Mass is expressed in
Kilograms
Weight is measured in
Newtons
All elements are organized in
Periodic table. Represented by 1,2,3 letter symbols
Molecule is a natural group of
Atoms held together by covalent bonds
Gases are easy to
Compress
Plasma conducts
Electric current. Affected by electric and magnetic fluids
Alkali metals become
Plasma
More than 99% of known matter in the universe is made of
Plasma
Exergonic reaction
Net release of free energy
Endergonic reaction
Net absorption of energy
