CHEM 110 General Chemistry King Abdul Aziz University Jeddah KSA 1 How to reach me? Dr. Hadi M. Marwani Associate Professor of Analytical and Environmental Chemistry • Faculty of Science, Chemistry Department • Room 362. • E-mail address: [email protected] • Website: www.kau.edu.sa/hmarwani 2 1 Text Book • Any General Chemistry Book • Selected textbooks: • Chemistry 10th Edition by Raymond Chang • General Chemistry System, Marwani and Albar at Dar Hafez • General Chemistry, McMurray • Chemistry, Ch i t Whitten Whitt • Chemistry, By C. Mortimer, 6th edition 3 Grading System 30% First midterm 30% Second midterm 40% Final exam 4 2 Grading System 95 – 100 % A+ 90 – 95 % A 85 – 89 % B+ 80 – 84 % B 75 – 79 % C+ 70 – 74 % C 65 – 69 % D+ 60 – 64 % D < 60 % F (Fail) 5 Chemistry: The Study of Change Chapter 1 General Chemistry 3 What is Chemistry? Chemistry is defined as "the study of matter and its change" Matter Matter is everything around us. Matter is anything that has a mass and occupy a space. Matter exists in three states: solid, liquid and gas. 7 Matter Pure substance Element Compounds Mixture Heterogeneous Homogeneous 8 4 Classification of Matter Matter Anything with mass and volume. Pure Substance Matter with constant composition Element Substance made up of only one type of atom Examples gold, silver, carbon, oxygen and hydrogen Compound Two or more elements that are chemically combined Examples - water, carbon dioxide, sodium bicarbonate, carbon monoxide Mixture Matter with variable composition Heterogeneous Mixture Mixtures that are made up of more than one phase Homogeneous Mixtures Also called solutions. Mixtures that are made up of only one phase Examples - sand, soil, chicken soup, pizza, chocolate chip cookies. Examples - salt water, pure air, metal alloys, seltzer water. 9 Pure Substance: A material with a constant composition such as NaCl, H2O, H2, CO2, and O2. Elements: Any substance that contains only one kind of an atom, such as H2 and O2. 2H2O ---> 2H2 + O2 Symbols for Some Elements Name of Element Name of Element Symbol Aluminum Al magnesium Mg Bromine Br Neon Ne Calcium Ca Nickel Ni Carbon C Nitrogen N Chlorine Cl Oxygen O Copper Cu phosphorus P Gold Au potassium K Helium He Silicon Si Hydrogen H Sodium Na I Sulfur Iodine 5 Symbol S Iron Fe Tin Sn Lead Pb Zinc Zn 10 Example: Write the symbols for the following: chlorine, copper, hydrogen, sodium, nickel, carbon, and oxygen. • • • • • • • • Answer: chlorine hl i (Cl) copper (Cu) hydrogen (H) sodium (Na) nickel (Ni) carbon (C) oxygen (O) 11 • Compound is a material that consists of two or more elements united together in definite proportion. • Compounds are represented by chemical formulas. • Chemical formula shows the symbols of the elements that are combined to make the compound. Examples of Some Chemical Formulas Compound Common N Name Chemical F Formula l calcium carbonate chalk CaCO3 carbon dioxide dry ice CO2 hydrochloric acid muriatic acid HCl hydrogen sulfide rotten-egg gas H2S sodium hydrogen carbonate (or sodium bicarbonate) baking soda NaHCO3 sodium chloride table salt NaCl sodium nitrate fertilizer NaNO3 sulfuric acid battery acid H2SO4 12 6 • Mixtures - Mixtures are made up of two or more substances that are physically combined. • The specific composition will vary from sample to sample. Homogenous mixtures - you cannot distinguish between its component such as milk, apple juice, and air. Heterogeneous mixtures - made up of more than one substance and theyy can be separated p p physically y y such as sandwich,, smoke coming g out of the car. 13 Physical and Chemical Properties Physical properties can be observed or measured without changing the composition of matter. Physical properties are used to observe and describe matter, such as appearance, texture, color, odor, melting point, boiling point, density, solubility, polarity, and many others. Chemical properties are only observable during a chemical reaction. For example, you might not know if sulfur is combustible unless you tried to burn it. Mater Change Physical change involves a change in the physical properties of the matter and it could be reversed, such as melting solid ice to liquid water. Chemical change involves a change in the chemical composition of the matter and it could not be reversed, such as burning sugar. 14 7 Example Classify each of the following changes as physical or chemical: g Iron Melting Melting Ice Burning Paper Chopping Wood Mixing Salt & Water Breaking Glass Burning Wood Mixing Peas & Carrots 15 Measurements The International System of Measurements (SI) There are seven SI base units. PROPERTY UNIT Length Meter m Mass Kilogram kg Time Second s Amount Mole mol Temperature Electrical Current Luminosity Derived Units: Units that are made d up off some combination bi ti off SI base units are called Derived Units. SYMBOL Kelvin K Ampere A Candela Cd PROPERTY UNIT SYMBO L Force Newton N kg m/s2 Pressure Pascal Pa N/m2 or kg/m s2 Energy Joule J kg m2/s2 or N m DEFINITION 16 8 SI Prefixes: used with the base units in order to increase or decrease the value that they represent. To remove a prefix from a value, insert the numerical value of the prefix in place of the symbol. Example: Convert 5.83 pm to meters Replace "p" with x 10-12 = 5.83 x 10-12 m To insert a prefix into a value, insert both the prefix and the inverse of its numerical value. PREFIX SYMBO L exa- E 1 000 000 000 000 000 000 (1018) peta- P 1 000 000 000 000 000 (1015) tera- T 1 000 000 000 000 (1012) Giga G 1 000 000 000 (109) Mega M 1 000 000 (106) NUMERICAL EQUIVALENT Kilo K 1000 (103) hecto- H 100 (102) deca- Da 10 (101) deci- D 0.1 (10-1) Centi C 0.01 (10-2) milli- M 0.001 (10-3) micro-  0.000 001 (10-6) N 0.000 000 001 (10-9) nanopico- P 0.000 000 000 001 (10-12) femto- F 0.000 000 000 000 001 (10-15) atto- A 0.000 000 000 000 000 001 (10-18) Example: Convert 0.000462 g to milligrams (note that the inverse of milli is 10+3) = 0.000462 x 10+3 mg = 4.62 x 10-1 mg OR 0.462 mg 17 K = 0C + 273.15 273 K = 0 0C 373 K = 100 0C 0F = 9 x 0C + 3 32 5 32 0F = 0 0C 212 0F = 100 0C 18 9 Convert 172.9 0F to degrees Celsius. = 9 x 0C + 32 5 0F – 32 = 9 x 0C 5 0F 5 x (0F – 32) = 0C 9 0C = 5 x (0F – 32) 9 0C = 5 x (172 (172.9 9 – 32) = 78.3 78 3 9 19 Density Density is an important property, which can be used to help determine the identity of an unknown substance. densiy  mass ( g ) volume (ml ) A student determines that a piece of an unknown material has a mass of 5.854 g and a volume of 7.57 cm3. What is the density of the material, rounded to the correct number of significant figures? densiy  mass (g ) 5.854( g )  volume (cm 3 ) 7.57(cm 3 ) d = 0.77331571994 g/cm3 = 0.773 g/cm3 20 10