Chapter 1 Chemistry 111 Lecture 1 1 What is Chemistry a Chemistry the properties of matter and how they interact change b Matter anything that takes up space and has mass i Made up of atoms and molecules ii Described by properties characteristics 1 When describing properties matter can be studied at macroscopic scale can be seen with naked eye or atomic scale tools needed to see what s being studied 2 Element the most basic unit of matter can t be broken down into more pure substances a Atom smallest unit of an element elements made up of one type of atom for example oxygen is only made up of oxygen atoms 3 Chemical compound made when two or more elements come together can be made up of more than one kind of atom come together in bonding such as covalent or ionic bonding 4 Molecules made up of more than one atom either of the same element or from atoms in a compound c Chemistry studies the composition of matter the atoms they are made of i Physical properties usually studied at the macroscopic level don t change the chemical composition of matter when observed ii Physical change change in physical property chemical composition stays the same 1 Examples of physical properties state of matter smell color flamboyancy density conductivity opacity melting and boiling points 2 States of Matter a Solid dense particles can t overcome attraction to each other defined shape atoms molecules packed together closely b Liquid dense some interactions between atoms and molecules shape determined by container substance is in atoms and molecules are close but there is room for them to flow c Gas no interactions between atoms and molecules no fixed shape or volume atoms and molecules move around haphazardly move rapidly past each other i States of matter change when energy is added or taken away such as heat melting point freezing point condensation iii Chemical properties can change the chemical composition of matter sometimes through interactions in substances 1 Example of chemical property ability to oxidize iv Chemical change change in chemical composition of matter reactions chemical bonds made or broken v Mixtures substances made of more than one element can be separated physically without changing chemical compositions of separate substances 1 Homogeneous uniformly mixed particles example salt dissolved in water 2 Heterogeneous mixture isn t uniform example sand in water 2 Units Used in Chemistry a Scientists record measurements on the SI system because it can be understood universally b SI system is based on units of 10 i Examples of SI units 1 Meter for length 2 Kilogram for mass 3 Cubic meter for volume ii Values for units can be written using scientific notation which is written in the form some number x 10x c Dimensional analysis used to convert factors
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