CHM 1045 Chapter 1 Notes 09 20 2015 Chemistry The study of matter and the changes it undergoes A basic knowledge of chemistry is needed for every other natural science The scientific method systematic approach to research 1st define the problem 2nd perform experiment while collecting qualitative and quantitative data interpret the data form a hypothesis and further experiments are done to validate the hypothesis Law a concise statement of a relationship between phenomena that is always the same under the same conditions Substances and Mixtures Substance a form of matter that has a definite composition and distinct Mixture combo of two or more substances in which the substances retain their distinct identities Homogenous mixture composition of the mixture is the same properties throughout Heterogeneous mixture composition is not uniform Any mixture heterogeneous or homogenous can be separated by physical means into pure components Elements and Compounds Element a substance that cannot be separated into simpler substances 118 elements have been identified when two or more elements mix the properties of the original elements can change compound a substance composed of atoms from two or more elements chemically united in fixed proportions Three states of matter solid liquid and gas solid liquid gas liquid gas solid liquid gas liquid solid solid gas melting evaporation condensation freezing deposition sublimation Substances can be identified by their properties Physical property anything that can be measured or observed without the composition or identity of a substance Chemical property anything observable by carrying out a chemical change Extensive properties depends on how much matter is being considered ie mass volume Intensive properties doesn t depend on how much matter is being considered ie density Measurement Meter stick measures length or scale Buret pipette or graduated cylinders measure volume Balance measures mass Thermometer measures temperature These tools measure macroscopic properties which can be determined directly Si Units Base Quantity Length Mass Time Electrical current Temperature Amount of substance Luminous intensity Name of Unit meter kilogram second ampere Kelvin mole Candela Symbol m Kg s A K Mol cd Prefixes Prefix Tera Giga Mega Kilo Deci Centi Milli Micro Nano Pico Symbol T G M k d c m n p Meaning 1012 109 106 103 10 1 10 2 10 3 10 6 10 9 10 12 Mass and Weight Mass a measure of the amount of matter in an object Weight the force that gravity exerts on an object Volume Meter is the Si unit of length and the SI unit for volume is m3 but cm3 is most common Liter is also a common unit of vol 1 L 1000 mL 1000 cm3 1 dm3 1 mL 1cm3 Density d m v since it s an intensive property it does not rely on the quantity of pass percent g mL is the most common unit for solid and liquid densities 1 g cm3 1g mL Temperature Scales Three temperature scales are commonly used Fahrenheit Celsius and Kelvin To convert Fahrenheit to Celsius C F 32 F x 5 C 9 F To convert Celsius to Fahrenheit F 9 F 5C x C 32 F For Celsius to Kelvin add C 273 K CHM 1045 Chapter 2 Notes 09 20 2015 Atomic Theory 1 Elements are made of tiny things called atoms 2 all atoms of a given element are identical but atoms of different elements are not 3 compounds are made from atoms of different elements 4 a chemical reaction involves the separation combination or rearrangement of atoms John Dalton in 1808 gave definition to atoms and began the era of chemistry Atom most basic unit of an element Atoms are composed of subatomic particles electrons protons and Radiation the emission and transmission of energy through space in the neutrons form of waves Electrons negatively charged particles Atomic number the number of protons in the nucleus of an element Mass number total number of neutron and protons in the nucleus of an atom in an element Isotopes elements with the same atomic number but different number of neutrons in the element The 6 7 and 8 are the mass numbers of the lithium isotopes The 3 is the atomic number Mass number atomic number number of neutrons Periodic Table Periodic Table A chart in which elements having similar chemical and physical properties are grouped together Elements are arranged by atomic number in horizontal rows called periods Groups or Families are placed in vertical columns according to similar chemical properties The elements can be broken down into 3 families metals non metals and metalloids Metal a good conductor of heat and electricity Non metal poor conductor of heat and electricity Metalloid has properties that are intermediate between those of metals and non metals Ionic compound a compound consisting of a metal and a non metal Covalent compound a compound consisting of two non metals Monatomic cations metals For the elements in the columns headed by Li Be and B simply say the element name followed by ion Na sodium ion Monatomic transition metal cations this is the element name followed by the charge on the cation expressed with Roman numerals within parentheses Fe 2 is iron II Exception Ag Zn 2 and Cd 2 may be treated as the monatomic cations above as their charge is unambiguous It is not incorrect to include Roman numeral charges just bad form Polyatomic cations NH4 ammonium ion Hg2 2 mercury I ion Monatomic anions non metals End the element name with ide Cl is chloride O 2 is oxide Polyatomic anions CO3 2 NO3 1nitrate SO4 2 PO4 3 1chlorate ClO3 carbonate sulfate phosphate BINARY ACIDS containing two elements HX Apply hydro element name ic acid HCl is hydrochloric acid OXYACIDS of the form HXO Apply anion name ate to ic ite to ous acid H2SO4 sulfuric acid H2SO3 sulfurous acid CHM 1045 Chapter 3 Notes 09 20 2015 The mass of an atom depends on the number of p e and n it contains Atomic mass the mass of an atom in an atomic mass unit Atomic mass unit a mass equal to 1 12th the mass of one carbon 12 atom Carbon 12 has 6 protons and 6 neutrons making it s atomic mass 12 amu the masses of all elements are relative to this Average atomic mass the average mass of all the isotopes Carbons average atomic mass is 12 01 instead of just 12 because of carbon s other isotopes Carbon 12 is just the most naturally occurring Avogadro s number and Molar Mass Chemists measure atoms and molecules in moles A mole is the amount of substance that contains as many entities as 12 grams of a carbon 12 isotope The actual number of atoms in 12 g of C 12 is Avogadro s number Avogadro s number NA 6
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