CHM1045 Exam #1 Study MaterialsChapter 1Composition of Matter: Atoms & Molecules- Atomso Submicroscopic particleso Fundamental building blocks of all matter- Moleculeso 2+ atoms attached together Attachments = bondso Come in different shapes & patterns- Chemistry: The science that seeks to understand the behavior of matter by studying the behavior of atoms and moleculesStructure Determines Properties- The properties of matter are determined by the atoms and molecules that compose itCarbon Monoxide (CO) Carbon Dioxide (CO2)- Composed of 1 carbon atom & 1 oxygen atom- Colorless, odorless gas- Burns with a blue flame- Binds to hemoglobin- Composed of 1 carbon atom & 2 oxygen atoms- Colorless, odorless gas- Incombustible- Does not bind to hemoglobinFrom Observation to Understanding- Hypothesis: A tentative interpretation or explanation for a single or small number of observationso Falsifiable – Confirmed or refuted by other observationso Tested by experiments – validated or invalidated- Similar observations made consistently Scientific Lawo A statement of a behavior that is always observedo Summarizes past observations & predicts future oneso Law of Conservation of Mass- Theory: A general explanation for the manifestation and behavior of all natureClassification of Matter1CHM1045 Exam #1 Study Materials- Matter: Anything that has mass and occupies spaceo Classified based on its physical state – solid, liquid, or gasState Shape Volume Compress FlowSolid Fixed Fixed No NoLiquid Indefinite Fixed No YesGas Indefinite Indefinite Yes YesFixed = Keeps shape when placed in a containerIndefinite = Takes the shape of the containerSolids- The particles in a solid are packed close together and are fixed in positiono May vibrate- 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 flowing2CHM1045 Exam #1 Study Materials- Degree of movement – VibrateLiquids- 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 & rotateGases- In the gas state, particles have complete freedom from each other- 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 togethero Gases are compressible- Because the particles are moving freely, gases expand to fill and take the shape of their container, and will flow- Degree of movement – Vibrate, rotate, translate (move wherever they want)Classification of Matter by CompositionMade of one type of particle Made of multiple types of particlesAll samples show the same characteristics Samples may show different characteristicsClassification of Pure Substances- Elements: Substances that cannot be broken down into simpler substances by chemical reactionso Basic building blocks of mattero Composed of a single type of atom- Compounds: Substances that can be decomposedo Chemical combinations of elementso Composed of molecules that contain 2+ different kinds of atomso All molecules of a compound are identical, so all samples of a compound behave the same way- Most natural pure substances are compounds3CHM1045 Exam #1 Study MaterialsMade of 1 type of atom Made of 1 type of molecule, or array of ionsSome elements found as Molecule contain 2+ different kinds of atomsmulti-atom molecules in natureCombine together to make compoundsClassification of Mixtures- Homogeneous: Mixture that has uniform composition throughouto Every piece of a sample has identical characteristics, but another sample with the same components may have different characteristicso Atoms or molecules mixed uniformly- Heterogeneous: Mixture that does not have uniform composition throughouto Contains regions within the sample with different characteristicso Atoms or molecules not mixed uniformly4CHM1045 Exam #1 Study MaterialsMade of multiple substances, Made of multiple substances, but appears to be one substancewhose presence can be seen All portions of a sample have the same composition & propertiesPortions of a sample have different composition & propertiesEx) Oil & water Ex) Ethanol & waterChanges in Matter- Physical Changes: Changes that alter the state or appearance of the matter without altering the composition- Chemical Changes: Changes that alter the composition of the mattero During chemical changes, the atoms that are present rearrange into new molecules, but all of the original atoms are still presentPhysical Changes in Matter- Boiling of water = physical changeo Water molecules are separated from each other, but their structure and composition do not change- All phase changes = physical changeso Evaporationo Sublimation Ex) Subliming of dry iceo Freezingo Meltingo Condensing- Dissolving5CHM1045 Exam #1 Study Materialso Ex) Dissolving sugar into waterChemical Changes in Matter- Rusting of iron = chemical changeo 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- BurningEnergy Changes in Matter- Changes in matter, both physical and chemical, result in the matter either gaining or releasing energy- Energy: The capacity to do work- Work: The action of a force applied across a distance6CHM1045 Exam #1 Study Materialso A force is a push or pull on an objecto Electrostatic force is the push or pull on objects that have an electrical chargeEnergy of Matter – Kinetic & Potential- Kinetic Energy: Energy of motiono Motion of the atoms, molecules, and subatomic particleso Thermal (heat) energy is a form of kinetic energy because it is caused by molecular motion- Potential Energy: Energy that is stored in the mattero Due to the composition of the matter and its position in the universeo 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 sameo Law of Conservation of EnergyPotential to kinetic energyThe Standard Units- Scientists have
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