Lecture 1Chemistry 1211Chapter 1:Matter and MeasurementChemistry-the study of matter and energy; it is a science that tries to understand the reactivity, transformations, properties, structures and composition of atoms and molecules. Observation- an act or instance of viewing or noting a fact or occurrence for some scientific or other special purpose.Law- based on repeated experimental observations that describe some aspect of the world.Hypothesis- a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigationTheory- a group of ideas to explain why something happens.States of Matter-Solids-Rigid shape/definite volume-Atoms or molecules pack close together in fixed locations-Although the atoms and molecules vibrate, they do not move around or pass each other.-Consequently, solids have fixed volume and rigid shape.-Solid matter may be crystalline solids or Amorphous solids.Crystalline solids- Atoms and molecules are in patterns with long in range repeating orderLecture 1Amorphous solids- Atoms and molecules do not have any long range order.-Liquids-Takes shape of the container/definite volume-Pack about as closely as they do in solid matter but they are free to move relative to each other.-Has definite volume but no definite shape.-Assumes the shape of its container-Gasses-Atoms and molecules have a lot of space between them -They are free to move relative to one another-The qualities make gases compressibleClassification of matter by substance-Pure Substance-Made up of only one component and its composition is invariant.-Categorized into 2 types; Elements and Compounds-Elements-cannot be chemically broken down into smaller substances.-Compounds-Substance composed of 2 or more elements in fixed definite proportions.-Mixture-By contrast, a substance composed of 2 or more components in proportions that can vary from one sample to another.-Mixtures can be categorized into Heterogeneous mixtures and Homogeneous mixtures.-Heterogeneous mixture-One in which the composition varies from one region of the mixture to another.-Made or multiple substances whose presence can be seen. Ex: a salt and sand mixture.Lecture 1-Portions of a sample of heterogeneous mixtures have different compositions and properties.-Homogeneous mixture-One made of multiple substances, but appears to be one substance-All portions of a sample have the same composition and properties. Ex: sweetened tea.Separating mixtures-Mixtures are separable because of the different components have different physical and chemical properties.-Various techniques that exploit these differences are used to achieve separation.-3 different ways of separation mixtures include Decanting, Distillation, and Filtration.-Decanting- carefully pouring mixture into another container Ex: sand and water-Distillation- Homogeneous mixture separating process.-Filtration- Process in which a mixture is poured through filter paper in a funnel.Physical and Chemical Changes-Physical Change-Changes that alter only the state or appearance, but not the composition, are physical changes.-the atoms or molecules that compose a substitute do not change their identity during a physical change.-Ex: When water boils, it changes its state from a liquid to a gas.-The gas remains composed of water molecules, so this is a physical change.-Chemical Change-Changes that alter the composition of matter are chemical changes-During a chemical change, atoms rearrange, transforming the original substance into different substances.-Ex: Rusting iron is a chemical change.Physical and Chemical Properties-Physical Properties-Property that a substance displays without changing its composition.Lecture 1-Ex: smell of gasoline is a physical change-Odor, taste, color, appearance, boiling point, melting point, are all physical properties.-Chemical Properties-Property that a substance displays only by changing its composition via, a chemical change or chemical reaction.-Ex: The flammability of gasoline, in contrast, is a chemical property -Chemical properties include corrosiveness, acidity, and toxicity.Intensive and Extensive Properties-Intensive properties-properties whose value is "independent of the quantity" of matter. -Often used to identify the type of matter.-Ex: Density, boiling point, melting point, odor, and color.-Extensive properties-Properties whose properties cannot be used to identify what type of matter something