CHM1045 Exam 1 Study Materials Chapter 1 Composition of Matter Atoms Molecules Atoms o Submicroscopic particles o Fundamental building blocks of all matter Molecules o 2 atoms attached together Attachments bonds o Come in different shapes patterns behavior of atoms and molecules Structure Determines Properties Chemistry The science that seeks to understand the behavior of matter by studying the The properties of matter are determined by the atoms and molecules that compose it Carbon Monoxide CO Composed of 1 carbon atom 1 Carbon Dioxide CO2 Composed of 1 carbon atom 2 oxygen oxygen atom Colorless odorless gas Burns with a blue flame Binds to hemoglobin atoms Colorless odorless gas Does not bind to hemoglobin Incombustible From Observation to Understanding Hypothesis A tentative interpretation or explanation for a single or small number of observations o Falsifiable Confirmed or refuted by other observations o Tested by experiments validated or invalidated Similar observations made consistently Scientific Law o A statement of a behavior that is always observed o Summarizes past observations predicts future ones o Law of Conservation of Mass Theory A general explanation for the manifestation and behavior of all nature Classification of Matter 1 CHM1045 Exam 1 Study Materials Matter Anything that has mass and occupies space o Classified based on its physical state solid liquid or gas Volume Shape Fixed Fixed Indefinite Fixed Indefinite State Solid Liquid Gas Fixed Keeps shape when placed in a container Indefinite Takes the shape of the container Compress Flow No No Indefinite Yes No Yes Yes Solids o May vibrate The particles in a solid are packed close together and are fixed in position Close packing of the particles results in solids being incompressible The inability of the particles to move around results in solids retaining their shape and volume when placed in a new container prevents the particles from flowing 2 CHM1045 Exam 1 Study Materials Degree of movement Vibrate Liquids The particles in a liquid are closely packed but have some ability to move around Close packing results in liquids being incompressible The ability of the particles to move allows liquids to take the shape of their container and to flow Don t have enough freedom to escape expand to fill the container Degree of movement Vibrate rotate In the gas state particles have complete freedom from each other Gases The particles are constantly flying around bumping into each other and the container There is a lot of empty space between the particles therefore the particles can be squeezed closer together o Gases are compressible container and will flow Because the particles are moving freely gases expand to fill and take the shape of their Degree of movement Vibrate rotate translate move wherever they want Classification of Matter by Composition Made of one type of particle All samples show the same characteristics Made of multiple types of particles Samples may show different characteristics Classification of Pure Substances reactions Elements Substances that cannot be broken down into simpler substances by chemical o Basic building blocks of matter o Composed of a single type of atom Compounds Substances that can be decomposed o Chemical combinations of elements o Composed of molecules that contain 2 different kinds of atoms o All molecules of a compound are identical so all samples of a compound behave the same way Most natural pure substances are compounds 3 CHM1045 Exam 1 Study Materials Made of 1 type of atom Some elements found as multi atom molecules in nature Combine together to make compounds Classification of Mixtures Made of 1 type of molecule or array of ions Molecule contain 2 different kinds of atoms Homogeneous Mixture that has uniform composition throughout o Every piece of a sample has identical characteristics but another sample with the same components may have different characteristics o Atoms or molecules mixed uniformly Heterogeneous Mixture that does not have uniform composition throughout o Contains regions within the sample with different characteristics o Atoms or molecules not mixed uniformly 4 CHM1045 Exam 1 Study Materials Made of multiple substances but appears to be one substance All portions of a sample have the same composition properties Physical Changes Changes that alter the state or appearance of the matter without Chemical Changes Changes that alter the composition of the matter o During chemical changes the atoms that are present rearrange into new molecules but all of the original atoms are still present o Water molecules are separated from each other but their structure and Made of multiple substances whose presence can be seen Portions of a sample have different composition properties Ex Oil water Changes in Matter altering the composition Ex Ethanol water Physical Changes in Matter Boiling of water physical change composition do not change All phase changes physical changes Ex Subliming of dry ice o Evaporation o Sublimation o Freezing o Melting o Condensing Dissolving 5 CHM1045 Exam 1 Study Materials o Ex Dissolving sugar into water Chemical Changes in Matter Rusting of iron chemical change o Iron atoms in the nail combine with oxygen atoms from O2 in the air to make a new substance rust with a different composition Processes that release high amounts of energy Burning Energy Changes in Matter releasing energy Changes in matter both physical and chemical result in the matter either gaining or Energy The capacity to do work Work The action of a force applied across a distance 6 CHM1045 Exam 1 Study Materials o A force is a push or pull on an object o Electrostatic force is the push or pull on objects that have an electrical charge Energy of Matter Kinetic Potential Kinetic Energy Energy of motion o Motion of the atoms molecules and subatomic particles o Thermal heat energy is a form of kinetic energy because it is caused by molecular motion Potential Energy Energy that is stored in the matter o Due to the composition of the matter and its position in the universe o Chemical potential energy arises from electrostatic forces between atoms molecules and subatomic particles You can interconvert kinetic energy potential energy the total amount of energy remains the same o Law of Conservation of Energy Scientists have agreed on a set of international standard units for comparing all our measurements called the SI units o Systeme International SI International System Potential
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