Organic-Inorganic Chemistry Notes PDF

INORGANIC CHEMISTRY  UNIT 1 INTRODUCTION TO CHEMISTRY Lesson 1: Matter and Its Properties Lesson 2: Measurements Lesson 3: Atoms, Molecules, and Ions Lesson 4: Mole Concept Jens Martensson 2 LESSON 1: MATTER AND ITS PRO...

INORGANIC CHEMISTRY  UNIT 1 INTRODUCTION TO CHEMISTRY Lesson 1: Matter and Its Properties Lesson 2: Measurements Lesson 3: Atoms, Molecules, and Ions Lesson 4: Mole Concept Jens Martensson 2 LESSON 1: MATTER AND ITS PROPERTIES OBJECTIVES OF THE DAY 1 2 I will be able to describe the particulate nature of the different forms of matter; I will be able to classify the properties of matter; I will be able to differentiate pure 3 4 substance and mixtures; elements and compounds; homogeneous and heterogeneous mixtures; 5 6 Jens Martensson 3 LESSON 1: MATTER AND ITS PROPERTIES OBJECTIVES OF THE DAY I will be able to recognize the formulas of some common substances; 1 2 I will be able to discuss methods to separate the components of a mixtures; and I will be able to recognize chemical 3 4 substances present in some consumer products 5 6 Jens Martensson 4 Activity 1: What is Matter? MATTER Jens Martensson 5 Matter is anything that has mass and occupies space. Everything on earth has mass and takes up space. Jens Martensson 6  PARTICLES COMPOSING MATTER These are the These are particles These are groups of smallest unit of that have gained or two or more atoms matter that can’t be lost one or more of that are chemically broken down their valence bonded. chemically. electrons. ATOMS MOLECULES IONS Jens Martensson 7  STATES OF MATTER SOLID LIQUID GAS Activity 2: Table Completion Jens Martensson 8 Jens Martensson 9 PLASMA THE 4TH STATE OF MATTER It is a hot ionized gas consisting of approximately equal numbers of positively charged ions and negatively charged electrons. The characteristics of plasmas are significantly different from those of ordinary neutral gases so that plasmas are considered a distinct "fourth state of matter." Jens Martensson 10 BOSE-EISTEIN CONDENSATE THE 5TH STATE OF MATTER It is a state of matter in which separate atoms or subatomic particles, cooled to near absolute zero. When they reach that temperature the atoms are hardly moving relative to each other; they have almost no free energy to do so. At that point, the atoms begin to clump together, and enter the same energy states. Jens Martensson 11  PROPERTIES OF MATTER According to changed According to dependence on involved during amount of matter measurements of the property. PHYSICAL CHEMICAL EXTENSIVE INTENSIVE PROPERTIES PROPERTIES PROPERTIES PROPERTIES These can be measured These are the ability of a These can be and observed without substance to react with It does not depend on affected by the size changing the composition other substances such as the size or amount of and amount of of the substance. air, water, and base. the sample. samples. Jens Martensson 12  PHYSICAL PROPERTIES INTENSIVE PHYSICAL PROPERTIES EXTENSIVE PHYSICAL PROPERTIES Color Melting Point Density Mass Volume Solubility Conductivity Malleability Length Luster Viscosity Boiling Point Temperature Odor Jens Martensson 13  CHEMICAL PROPERTIES CHEMICAL PROPERTIES DESCRIPTION 1. Combustibility Whether the substance undergoes combustion or not \ 2. Stability Whether the substance can be easily decomposed or not 3. Reactivity Whether it reacts with acids, bases, and oxygen, gas or not 4. Relative Activity Whether the material is more active or less active than other members of its chemical family 5. Ionization Whether it will break into charged particles when in solution with water or not. 6. Toxicity Whether substance can damage an organism or not. Jens Martensson 14 Activity 3 Group the characteristics of the give substance according to their physical (extensive or intensive) or chemical properties. CHARACTERISTICS OF SOME PHYSICAL PROPERTIES CHEMICAL PROPERTIES SUBSTANCES INTENSIVE EXTENSIVE 1. The water in the container has a volume of 100 mL and a mass of 99.8 g. It is colorless, and tasteless. It has a density of 0.998g/mL, boils at 100 degrees Celsius, and freezes at 0 degree Celsius. It does not burn. It causes Iron to rust. Jens Martensson 15 Activity 3 Group the characteristics of the give substance according to their physical (extensive or intensive) or chemical properties. CHARACTERISTICS OF SOME PHYSICAL PROPERTIES CHEMICAL PROPERTIES SUBSTANCES INTENSIVE EXTENSIVE 2. NaCl with a mass of 37.9 g is colorless, odorless, and salty solid crystals. It has melting point of 801 degree Celsius. When dissolved in 100 mL water, it conducts electricity. It reacts with silver nitrate to form a white precipitates. It also react with water to form chlorine gas, hydrogen gas, and sodium hydroxide. Jens Martensson 16  MATTER These are composed of two or It is a matter that has a PURE SUBSTANCE definite composition and MIXTURES more substances combined physically in various distinct properties composition It is the It contains two It is a solid, It is a mixture simplest form or more kinds of liquid, or HOMOGENEOUS gaseous mixture that HETEROGENOUS whose composition ELEMENT of matter since it COMPOUND atom chemically combined in MIXTURE has the same varies from one MIXTURE position to composed of definite proportions of its another within the only one kind proportion by components throughout sample. of atom. mass any given sample. Jens Martensson 17 Activity 4: Pure Substance or Mixture? 1. TABLE SUGAR 2. TABLE SALT Jens Martensson 18  PURE SUBSTANCE OR MIXTURE? 3. IODIZED SALT 4. DISTILLED WATER Jens Martensson 19  PURE SUBSTANCE OR MIXTURE? 4. SOFTDRINKS 5. OXYGEN GAS (TANK) Jens Martensson 20  PURE SUBSTANCE OR MIXTURE? 6. BROWN SUGAR 7. HUMAN BREATH Jens Martensson 21 Activity 5: HOMOGENEOUS OR HETEROGENEOUS? 1. RUBBING ALCOHOL 2. WATER &OIL Jens Martensson 22  HOMOGENEOUS OR HETEROGENEOUS? 3. SALT & PEPPER 4. CARBONATED SOFTDRINKS Jens Martensson 23  HOMOGENEOUS OR HETEROGENEOUS? 5. HUMAN BREATH Jens Martensson 24  SEPERATING MIXTURES Chemist separate mixtures by using different methods. Jens Martensson 25  SEPERATING MIXTURES Chemist separate mixtures by using different methods. 1. Filtration is a process of separating the components of a suspension 2. In Decantation the solid particles are allowed to settled first at the bottom and later, the liquid which is called supernatant is poured into another container leaving behind solid particle. 3. Evaporation is the process of converting liquid to gas, is useful in sorting mixtures such as salt solution. 4. Distillation is a process of separating a homogeneous mixture composed of two substances with different boiling points. Jens Martensson 26  SEPERATING MIXTURES Chemist separate mixtures by using different methods. 5. Magnetic Separation is the process of separating elemental metals from other particles in a mixture. 6. Melting is a process that can be used in extricating mixture that contain two substances with different melting points. 7. Sublimation is a process of changing solid to gas without passing through the liquid state. 8. In Centrifugation, the mixture is poured into a special tube in the centrifuge apparatus, and is allowed to spin using centrifugal force. The spinning motion forces the sediments to settle at the bottom. The liquid can be poured off from the solid particles. Jens Martensson 27 9. Chromatography is another method of separating complex mixtures. It has various methods that can be used in separating mixture such as paper chromatography, which makes used of an adsorbent (filter paper or chromatogram paper), then separation depends upon the solubility of each component in the solvent. Jens Martensson 28 PURE SUBSTANCES & MIXTURES IN CONSUMER PRODUCTS CONSUMER PRODUCT It is any item often bought for consumption. Convenience Product – those that appeal to a large segment of the market or those that are routinely bought. 1. Household Cleaning 2. Personal Care Product Jens Martensson 29 PURE SUBSTANCES & MIXTURES IN CONSUMER PRODUCTS HOUSEHOLD CLEANING MATERIAL The most commonly used cleaning products are bleach, soaps, and detergents. These products have different compositions, specific uses, precautions for use, and costs. Jens Martensson 30 PURE SUBSTANCES & MIXTURES IN CONSUMER PRODUCTS HOUSEHOLD CLEANING MATERIAL Bleach helps clean and whiten surfaces by generally lowering the stability of the chemical bonds in stain molecules. It can convert dirt into particles that can be easily washed away in conjunction with use of detergents. NaOCl (Sodium Hypochlorite) and H2O2 (Hydrogen Peroxide) are most common bleaching agents that are strong oxidizers; they can burn then skin and eyes especially if used in concentrated form. Jens Martensson 31 PURE SUBSTANCES & MIXTURES IN CONSUMER PRODUCTS HOUSEHOLD CLEANING MATERIAL Soap and Detergent are mixture of surfactants, water softeners, stain removers, enzymes and perfumes, among others. Surfactants render soaps and detergents capable of lowering the surface tension of water, which allows them to wet the surface to be cleaned. They also loosen and disperse water-insoluble solids making them washable with water. Soap and Detergents are generally not toxic and severely dangerous, but may cause irritation to the skin and eyes. Jens Martensson 32 PURE SUBSTANCES & MIXTURES IN CONSUMER PRODUCTS PERSONAL CARE PRODUCTS Personal Care product constitute a diverse group of materials that improve the overall appearance of a person. These products are used to generally cleanse and beautify. Examples of highly demanded personal care products are makeup, lotions, and toothpastes. Jens Martensson 33 LESSON 2: MEASUREMENTS OBJECTIVES OF THE DAY I will be able to describe the need for 1 2 measurement; I will be able to carry out simple measurements of length, volume, and mass; and 3 4 I will be able to differentiate the accuracy and the precision of a measurement 5 6 Jens Martensson 34 Keywords for the concepts to be learned; a.Measurements b.Unit of Measurements c. Accuracy d.Precision e. Significant figures f. Errors Jens Martensson 35 Measurements The study of matter requires a certain degree of measurements, a process of determining the extent of the dimensions, quantity, or extent of something. Questions such as “How much….?” ,“How long…?” and “How many…?” simple cannot be answered without resorting to measurement. Q1. Can you cite some situations in daily life where a measurement is important? Jens Martensson 36 Units of Measurements The most convenient system of units is the International System of Units (SI). This system is the modern versions of metric system. Jens Martensson 37 Units of Measurements The name of the fractional parts and the multiples of the base units are constructed by adding prefixes. These prefixes, shown in table, indicate the size of the unit relative to the base unit. Jens Martensson 38 Uncertainty in Measurements A measured quantity contains some digits that are exactly known and one digit that is estimated. The estimated digit produces uncertainty in measurements. Jens Martensson 39 Random Error and Systematic Error RANDOM ERROR (indeterminate error) is the uncertainty that arises from a scale reading which results from the uncontrolled variables in the measurement. It causes one measurement to differ slightly from the next. It comes from unpredictable changes during an experiment. Examples a. When weighing yourself on a scale, you position yourself slightly different each time. b. Measuring your height is affected by minor posture changes. Jens Martensson 40 Random Error and Systematic Error SYSTEMATIC ERROR (determinate error) is the uncertainty that may come from a flaw in the equipment used or design of an experiment. These error are usually caused by measuring instruments that are incorrect calibrated or are used incorrect. Examples a. A worn out instrument b. An incorrectly calibrated or tared instrument c. A person consistently take an incorrect measurements Jens Martensson 41 Precision and Accuracy Precision is the consistency of a result. If you measure a quantity several times and the values agrees closely with one another, then your measurement is precise.; however, if the values varied widely, then it is imprecise. Accuracy is determined when a certain quantitative value is relatively close to the “true value” Jens Martensson 42 Activity 6 Each dot is the result of a measurement whose value is indicated in the horizontal (or x-) axis. The plot presents the results of six measurements of the weight of a pebble whose true weight is 8.0 g. Determine whether each measurement is accurate or inaccurate, and precise or imprecise. Jens Martensson 43 Activity 7 Jens Martensson 44 Scientific Notation It is a simple way to write or keep track of very large or very small numbers without having to deal with a lot of zeros. It provides a convenient way of recording results and doing calculations. Jens Martensson 45 Jens Martensson 46 Activity 8 1. 0.012345698632 2. 1 230 945 3. 87 576 788 432 234 543 4. 0.O6OO789653 5. 11 987 Jens Martensson 47 Significant Figures Significant figures are the digits in any measurement that are known certainty with an additional one digit which is uncertain. RULES MEASURED NUMBERS NUMBER OF SIGNIFICANT 1. All nonzero digits are significant. 247 3 2. Zeroes between nonzero digits are significant. 20303 5 3. Zeroes to the left of the first nonzero digits 0.0200 3 are NOT significant Jens Martensson 48 Significant Figures RULES MEASURED NUMBERS NUMBER OF SIGNIFICANT 4. If the number is less than 1, then only the 0.003560 4 zeros at the end of the number and the zero between nonzero digits are significant. 5. If the number is greater than 1, then all the zeros written to the 35600.00 7 right of the decimal point are significant. Jens Martensson 49 Activity 9 Give the number of significant figures for each of the following measurements. 1. 2 365 mm 2. 309 cm 3. 5.030 g/mL 4. 0.0670 g 5. 3.60 x 10-4 Jens Martensson 50 Activity 10 Give the number of significant figures for each of the following measurements. 1. 0.476 kg 2. 89.7808 ft 3. 0.430 mg 4. 60.0 min 5. 1 x 107 Jens Martensson 51 Rules for Significant Figures in Fundamental Operations In addition and subtraction, the answer must have the same number of decimal places as the measured number with the least number of decimal places. In multiplication and division, the answer must have the same number of significant figures as the measured number with the lowest number of significant figures. Jens Martensson 52 Activity 11 Perform the following operations and write the answers in the proper number of significant figures. 1. 4.87 m + 36.578 m + 4.34 m 2. 8.9 mL ÷ 45 mL 3. 68.980 cm – 67.16 cm 4. 45.00 ft. x 3.00 ft. 5.14.4 g + 6.0 g Jens Martensson 53 Rules in Rounding Off Oftentimes, the answers to computations contain too many insignificant digits. Hence it becomes necessary to round off numbers to attain the insignificant figures. Rounding off, therefore, is the process of removing, insignificant digits from calculated number. Jens Martensson 54 Rules in Rounding Off The following rules should be applied to round off values to the correct number of digits. 1. For a series of calculations, carry extra digits through to the final result, then round off. 2. If the first digit to be deleted is…. a. 5 or greater, the last retained figure is increased by one b. 4 or less, the last retained figure is retained. Jens Martensson 55 Conversion of Units (Dimensional Analysis) Dimensional Analysis is a process in which a conversion factor written in a form of ratio is used to change units given in the data to the units desired. The following are steps to be followed in doing dimensional analysis. a. Write the unknown quantity that is sought, including the units. b. Write all known conversion factors needed c. Begin with what is known and then multiply it by the identified conversion factor, cancelling similar units to get the unknown units. Jens Martensson 56  METRIC AND ENGLISH CONVERSIONS QUANTITY METRIC ENGLISH CONVERSION g, Kg lb, oz 1lb = 454 g MASS 1kg = 2.2 lb 1 oz = 28.35g cm, m, in, ft, mi, 1 in = 2.54cm LENGTH km Å 1 m = 39.37 in 1 ft = 12 in 1 mi = 1.609 km 1 km = 0.62137 mi 1 Å = 10-10 m mL, L qt, pints, 1 qt =946 mL VOLUME cups, tsp, 1 L = 1.057 qt 1 L = 2.12 pints tbsp, fl 1 L = 4.23 cups oz, gal 1 tsp = 4.93 mL 1tbsp = 14.79 mL 1 fl oz = 29.06 mL 1 gal = 3.79 Jens L Martensson 57 Activity 12 Sample Problems! 1.The lemon juice drink contains 500.0 mg of vitamin C. Express the vitamin C content in grams. 2. A fitness drink measures 0.300 L. Express the volume in L 3. Calculate the number of centimeters in 53.5 inches. Jens Martensson 58 Density Measurement Density measurement is one of the common measurements done in the laboratory. It involves getting Mass, Volume and Temperature of an Object. A. Mass is the quantity of matter in the object. It is determined by weighing the object, using balance. The SI basic unit of mass is the Kilogram, but the gram is more convenient to use. Jens Martensson 59 Density Measurement B. Volume is the amount of space occupied by a substance. In liquids, the volume can be determined using a graduated cylinder, while solids, the volume can be determined by two methods. 1. For regularly shaped-solids, the volume formula for the particular shaped is used. Some formula that may be used are the following: Rectangular solid = L x W x H Cylindrical Solid = πr2h Cubic solid = S x S x S Spherical solid = 4/3 πr3 Jens Martensson 60 Density Measurement 2. For irregularly-shaped solids, the water displacement method is used. C. Temperature tells how hot or cold an object is. It is commonly marked either by oC (Celsius) or o F (Fahrenheit); although the SI basic unit for temperature is the K (Kelvin). To convert oC or oF to K, the following are used. K = oC + 273.15 K = (oF + 459.67) x 5/9 Jens Martensson 61 Density Measurement DENSITY is the ratio of the mass of an object to the volume it occupies. DENSITY = Jens Martensson 62 Activity 13 Sample Problems 1.A sample amount of sugar has a mass of 250.0 g and a volume of 157.3 cm3. What is its density in grams per cubic centimeter? 2. Gold metal has a density of 19.3 g/cm3. What is the volume in cubic centimeter of a 500.0 g bar of gold metal? Jens Martensson 63 Activity 14 Sample Problem 1. The volume and the mass of two objects (A & B) have been obtained in order to determine their densities, respectively. Identify which object is denser. OBJECT METHOD USED FOR DETERMINING THE VOLUME MASS A By measuring its dimension 90.0 g L = 2.0 cm, W = 2.5 cm H = 15 cm B By water displacement method: 65.0 g Final Volume (Water + object) = 100 mL Initial Volume (Water) = 80.0 mL Jens Martensson 64 Lesson 3: Atoms, Molecules and Ions OBJECTIVES OF THE DAY! I will be able to describe and discuss the basic laws of chemical change; I will be able to discuss how Dalton’s Atomic Theory could explain the basic laws of chemical changes; I will be able to give the information provided by the atomic number and mass number of an atom and its isotopes Jens Martensson 65 Lesson 3: Atoms, Molecules and Ions OBJECTIVES OF THE DAY! I will be able to differentiate atoms, molecules, and ions; I will be able to write the chemical formula of some molecules; I will be able to differentiate a molecular formula and an empirical formula; and I will be able to give the name of a compound, given its chemical formula. Jens Martensson 66 Keywords a. Law of Conservation of Matter h. Law of Definite Proportion b. Law of Multiple Proportion i. Dalton’s Atomic Theory c. Atomic number j. Mass number d. Isotope k. Atom e. Molecule l. Ion f. Chemical formula m. Molecular formula g. Empirical formula Jens Martensson 67 LAWS OF CHEMICAL CHANGE These laws were inferred from several experiments conducted during the 18th century using a balance for the measurements: 1. Law of Conservation of Mass 2. Law of Definite Proportion 3. Law of Multiple Proportion Jens Martensson 68 A. Law of Conservation of Mass ANTOINE LAVOISIER, a brilliant French chemist, formulated this law by describing one of his experiments involving mercuric oxide. He placed a small amount of mercuric oxide, a red solid, inside a retort and sealed the vessel tightly. Jens Martensson 69 A. Law of Conservation of Mass He weighed the system, and then subjected it to high temperature. During the heating, the red solid turned into a silvery liquid. This observation indicated that a chemical reaction took place. After which, the setup was cooled and then weighed. The weight of the system was found to be the same as before heating. Jens Martensson 70 A. Law of Conservation of Mass In a chemical reaction, no change in mass takes place. The total mass of the products is equal to the total mass of the reactant. Jens Martensson 71 B. Law of Definite Proportion A compound always contains the same constituent elements in a fixed or definite proportion by mass. If water samples coming from different sources are analyzed, all the samples will contain the same ratio by mass of hydrogen to oxygen. Jens Martensson 72 Sample Problems A pure sample of Sodium Flouride (NaF) contains 35g of Sodium. How many grams of Flourine are present in this sample? If there are 42g of H in a sample of pure Methane (CH4), How many grams of Carbon are present? If there are 19g of oxygen in a sample of Aluminum Oxide (Al2O3), How many grams of Aluminum are present? Jens Martensson 73 C. Law of Multiple Proportions If two elements can combine to form more than one compound, the masses of one element that will combine with a fixed mass of the other element are in a ratio of small whole numbers. Jens Martensson 74 Dalton’s Atomic Theory In 1808, John Dalton published his book A New System of Chemical Philosophy, where he proposed an atomic theory of matter that can explain chemical observations as predicted by the three fundamental laws. Jens Martensson 75 Dalton’s Atomic Theory The atomic theory comprised the following postulates: 1. Matter is made up of extremely small indivisible particles called atoms. Jens Martensson 76 Dalton’s Atomic Theory The atomic theory comprised the following postulates: 2. Atoms of the same element are identical, and are different from those of other elements. Jens Martensson 77 Dalton’s Atomic Theory The atomic theory comprised the following postulates: 3. Compounds are composed of atoms of more than one element, combined in definite ratios with whole number values. Jens Martensson 78 Dalton’s Atomic Theory The atomic theory comprised the following postulates: 4. During a chemical reaction, atoms combine, separate, or rearrange. No atoms are created and no atoms disappear. Jens Martensson 79  During the time of Dalton, the atom was believed to be the smallest particle comprising substances. However, before the end of the 19th century, experiments provided proof of the existence of smaller particles within the atom. Jens Martensson 80 Activity 15 Recall the particles contained in an atom (or the subatomic particles) and differentiate the particles in terms of location, charge, and relative mass by filling up the following table: Jens Martensson 81 Activity 15 Recall the particles contained in an atom (or the subatomic particles) and differentiate the particles in terms of location, charge, and relative mass by filling up the following table: Jens Martensson 82 Atomic Number and Mass Number An atom of an element may be represented in a certain configuration that includes its atomic number (Z) and Mass number (A), written as the left superscript and left subscript, respectively of the element symbol. mass number (A) Symbol of Element atomic number (Z) Jens Martensson 83 Atomic Number and Mass Number The atomic number of an element represents the number of protons in its nucleus. Because an atom as a whole is electrically neutral, the atomic number also specifies the number of electron present. ATOMIC NUMBER = NUMBER OF PROTONS = NUMBER OF ELECTRONS Jens Martensson 84 Atomic Number and Mass Number The mass number of an atom is the sum of the number of protons and neutrons in its nucleus. Thus, the mass number gives the number of subatomic particles present in the nucleus. MASS NUMBER = NUMBER OF PROTONS + NUMBER OF NEUTRONS Jens Martensson 85 Activity 16 COMPLETE THE TABLE BELOW Jens Martensson 86 Isotopes are toms of an element having the same atomic number but different mass number. The existence of isotopes was shown by mass spectroscopy experiments, wherein elements were found to be composed of several types of atoms, each with different masses. a. The atomic number identifies an element. The atoms of isotopes of an element have the same number of protons and electrons. b. The atoms of isotopes of an element differ in the number of neutrons. Jens Martensson 87 Atoms, Molecules and Ions Jens Martensson 88 Atoms, Ions and Molecules Of all the elements, only six exist as single atoms, namely Helium, Neon, Argon, Krypton, Xenon and Radon. Most matters are composed of ions formed from atoms. A molecule is a combination of at least two atoms in a definite proportion, bound together by covalent bonds. Jens Martensson 89 Ions When a neutral atom gain or loses one or more electrons, it becomes an electrically charged particles called ion. Jens Martensson 90 Ions Metals tend to lose electrons and become positively charged cations. Nonmetals, on the other hand, gain electrons and become negatively charged anions. The number of electron lost or gained is the charged number. Ions can be made up of only one atom (monoatomic) or more than one type of atom (polyatomic). Jens Martensson 91 Jens Martensson 92 Jens Martensson 93 Naming Monoatomic Ions Monoatomic ions are named based on the element. a. For cations, the name of the element is unchanged. If an element can form two ions of different charges, the name, which is usually derived from its Latin name, is modified by the suffix –ic for the ion with the higher charge, and –ous for that with the lower charge. Jens Martensson 94 Jens Martensson 95 Naming Monoatomic Ions b. The monoatomic anions are named by attaching the suffix –ide to the first few letters (root) of nonmetal name, Jens Martensson 96 Activity 17.1 Name the following cations below. Jens Martensson 97 Activity 17.2 Name the following anions below. Jens Martensson 98  Several anions are polyatomic and are named based on the atomic constituents and the suffix – ide. The most common examples are: a. OH- – hydroxide ion b. CN- – cyanide ion Jens Martensson 99  A number of polyatomic anions containing oxygen atoms are named based on the root word of the central (or non-oxygen) atom and the suffix –ate for the one with more oxygen atoms and –ite for the one with less oxygen atom. Some anions have common names ending with the suffix –ate. Jens Martensson 100 Jens Martensson 101 Chemical Formula The composition of a molecule or an ion can be represented by a chemical formula. The formula consists of the symbols of the atoms making up the molecule. If there is more than one atom present, a numerical subscript is used. Jens Martensson 102 Chemical Formula There are two types of chemical formula - the molecular formula and empirical formula. Jens Martensson 103 Chemical Formula Molecular Formula indicates the actual number of each element in a compound. Emperical Formula is the simplest chemical formula. It only shows relative ratio between the number of atoms of the different elements present in the compound. Jens Martensson 104 Activity 18 Write the empirical formula of the following molecules. 1. C2H4O2 2. C8H12N4 3. C8H10 4. P4O10 5. PH3 Jens Martensson 105 Naming Compounds A. IONIC COMPOUNDS (cation and anion) 1. For Binary Compounds, metal cations take their names from the elements, while the anion take the first part of the name of element , and add the suffix –ide end. CATION ANION COMPOUND NAME OF COMPOUND Na+ O-2 Na2O Sodium oxide Mg+2 N-3 Mg3N2 Magnesium nitride Al+3 O-2 Al203 Aluminum Oxide Jens Martensson 106 Naming Compounds 2. For Ternary Compounds, the cation goes first in its name before the polyatomic ion which usually ends with –ite or -ate CATION ANION COMPOUND NAME OF COMPOUND Na+ NO3-1 NaNO3 Sodium Nitrate Na+ NO2-1 NaNO2 Sodium Nitrite Jens Martensson 107 Naming Compounds 3. For compounds containing a metallic ion of variable charge, either the classical method or the stock method of naming may be used. In the classical method, the name of metallic ions ends in – ous (for lower charge) and –ic (for higher charge) In the stock method, the metal is named first followed by the value of the charge written in roman numeral (enclosed in parenthesis) Jens Martensson 108 Naming Compounds B. MOLECULAR COMPOUNDS (TWO NONMETALS) For one pair of elements that form several different compounds, Greek prefixes are used to determine the number of each element in the compound. For the first element, the prefixes “mono” is omitted. Examples CO – carbon monoxide CO2 – carbon dioxide N2O4 – dinitrogen tetraoxide Jens Martensson 109 Jens Martensson 110 Naming Compounds B. MOLECULAR COMPOUNDS (TWO NONMETALS) For binary compounds, place the name of the first element; then follow it with the second element. The second element is named by adding –ide to the root of the element name. Examples: a. HCl – hydrogen chloride b. HBr – hydrogen bromide Jens Martensson 111 Naming Compounds B. MOLECULAR COMPOUNDS (TWO NONMETALS) For binary compounds considered as acids, use the prefix hydro- followed it with second element. The second element is named by adding –ide to the root of the element name. Examples a. HCl – hydrogenchloric acid b. HBr – hydrobromic acid Jens Martensson 112 Naming Compounds B. MOLECULAR COMPOUNDS (TWO NONMETALS) Oxy-acids, those that contain hydrogen, oxygen and another element, is named in two ways – a. For anions ending with –ate, change –ate to –ic; then, follow it with the word acid. b. For anions ending with –ite, change –ite to –ous; then follow it with the word acid. Jens Martensson 113 Lesson 4: Mole Concept OOTD: OBJECTIVES OF THE DAY At the end of this lesson, the students must be able to explain the meaning of average atomic mass define a mole; illustrate Avogadro’s number with examples; determine the molar mass of elements and compounds; calculate the mass of a given number of moles of an element or compound, or vice versa; and calculate the mass of a given number of particles of an element or compound, or vice versa. Jens Martensson 114 PERFORMANCE TASK THIRD QUARTER – GENERAL CHEMISTRY 1 History of the Atomic Structure 1. J.J Thomson’s Plum Pudding Model 2. John Dalton’s Billiard Ball Model 3. E. Rutherford’s Nuclear Model 4. Niels Bohr’s Planetary Model 5. Schrodinger & Heisenberg Quantum Mechanical Model Jens Martensson 115  Ms. Lilia sells shelled peanuts in a store. But she meets customers asking for 150 peanuts, another for 750 peanuts, and another for 2,000 peanuts. Obviously, it will take Ms. Lilia a very long time to count the peanuts. What would be another way to count them? Jens Martensson 116 Jens Martensson 117 Atomic Mass and Atomic Mass Unit Question: Is it possible to use the same procedure to count atoms. Why or why not? Whether it is peanuts or mongo beans or candies or atoms, the procedure should be the same. The problem, however, is atoms are very, very small and it is not possible to see them and count them individually to get the average mass. We need to look for another way to get the average mass of the atom. Jens Martensson 118 Atomic Mass and Atomic Mass Unit Experiments have shown that atoms have different masses relative to one another. For example, a Mg atom is experimentally reported to be twice as heavy as a carbon atom; a silicon atom is twice the mass of a nitrogen atom. It is possible to make a relative scale if one atom is chosen as the reference or standard atom against which the masses of the other atoms are measured. Jens Martensson 119 Atomic Mass and Atomic Mass Unit By international agreement, the reference atom chosen is the C-12 isotope which contains six protons and six neutrons. By definition, one atom of C-12 has a mass of exactly 12 atomic mass units (amu). One amu, therefore, is one-twelfth (1/12) the mass of a C-12 atom. Jens Martensson 120 Atomic Mass and Atomic Mass Unit Example The atomic mass of Cu-63 is 62.93 amu. This means that relative to C-12, one atom of Cu-63 is 62.93/12 or 5.244 times the mass of a C-12 atom. Try This! One atom of Se-77 is 6.410 times as heavy as an atom of C-12. What is the atomic mass of Se-77? Jens Martensson 121 Average Atomic Mass The atomic mass of the atoms of an element is the average atomic masses of the naturally occurring isotopes of this element. For example The average atomic mass of Oxygen is 15.999, not 16.00 The 15.999 is calculated by considering the naturally-occurring isotopes of Oxygen, namely Oxygen-16, Oxygeny-17 and Oxygen-18 The periodic table provides the average atomic mass which takes into account the different isotopes of an element and their relative abundances. NOTE: It is not a simple average that is taken but a weighted average Jens Martensson 122 Average Atomic Mass Average atomic masses are obtained by multiplying the mass of an isotopes by its fractional abundance, as shown as follows. ELEMENT MASS NUMBER ISOTOPIC MASS % ABUNDANCE AVERAGE ATOMIC MASS 16 15.9949 u 99.76% Oxygen 17 16.9991 u 0.04% 15.999 u 18 17.9992 u 0.20% Isotopes of elements occur in different abundances. Some are more abundant than others. 1. Chlorine has two isotopes. The natural abundance of Cl-35 is 75% while that of Cl-37 is 25%. This means that if you have 100 atoms of chlorine, 75 of them will be Cl-35 and 25 of them will be Cl-37. Jens Martensson 123 2. Magnesium, on the other hand, has three isotopes with varying abundances: Mg-24,Mg-25, and Mg-26, 11.01 have 78.99%, 10.00%, and 11.01% abundance, respectively. 3. For carbon, the natural abundance of C-12 is 98.90% while that of C-13 is 1.10%. The atomic mass of C-13 has been determined to be 13.00335 amu while that of C-12 is exactly 12 amu. Relative Atomic Mass is the ratio of the average atomic mass of an atom to one atomic mass unit (amu) Hence, its value is similar with average atomic mass, except that it has no unit. Jens Martensson 124 Activity 19 1. Copper has two stable isotopes with the following masses and % abundances: Cu-63 (62.93 amu, 69.09% abundance) and Cu-65 (64.9278 amu, 30.91% abundance). Calculate the average atomic mass of copper. Jens Martensson 125 The Avogadro’s Number In the SI system, the mole (mole) is defined as the amount of substance containing the same number of particles as there are atoms in exactly 12 g of carbon- 12 isotope. One mole of a substance is equivalent to the Avogdro’s number of particles 6.02 x 1023 This number is so-named in honor of the Italian scientist, Amadeo Avogadro Jens Martensson 126 The Avogadro’s Number Thus, based from the definition. It can be said that a. One mole of an element is numerically equal to its atomic mass unit. b. One mole of an element contains 6.02 x 1023 atoms c. One mole of molecular compound contains 6.02 x 1023 molecules d. One mole of ionic compound contains 6.02 x 1023 cations and 6.02 x 1023 anions Jens Martensson 127 Molar Mass The molar mass of a compound (molecular or ionic) is the mass in grams of one mole of a substance. It is numerically equal to the sum of the masses of the elements (in amu) that make up the compound. The molar mass is obtained by multiplying the number of atoms by the atomic mass of each element, and getting the sum. The unit for molar mass is g/mol. Jens Martensson 128 Molar Mass The molar mass of a compound (molecular or ionic) is the mass in grams of one mole of a substance. It is numerically equal to the sum of the masses of the elements (in amu) that make up the compound. The molar mass is obtained by multiplying the number of atoms by the atomic mass of each element, and getting the sum. The unit for molar mass is g/mol. Jens Martensson 129 Activity 20 Calculate the molar mass of the following compounds 1. C3H5N3O9 2. (NH2)2 CO 3. Hg(OCN)2 Jens Martensson 130 Formula Mass and Molecular Mass Formula Mass is used for compounds that exists as ions, such as NaCl. It is expressed in amu or u, and is numerically equal to the molar mass expressed in grams per mole of a substance. IONIC COMPOUND COMMON NAME MOLAR MASS FORMULA MASS NaCl Table Salt 58g/mol 58 amu CaO Quicklime 56g/mole 56 amu Molecular Mass is used for compounds that exist as molecules, such as water (H2O) It is numerically equal to the molar mass and has a unit amu. MOLECULE COMMON NAME MOLAR MASS MOLECULAR MASS CO2 Dry Ice 44g/mol 44 amu C12 H22 O11 Dextrose 342g/mole 342 amu Jens Martensson 131 Calculation Involving Formulas The Avogadro’s number and molar mass are important to enable conversions between mass and moles of atoms or molecules, ion and vice versa. The following are the conversion factors that can be used in calculations involving formulas. Where X represents the symbol of atoms, ions, or the formula of the compound. and. ( ) Jens Martensson 132 Sample Problems A. Conversion between atoms, molecules, or ions and mass 1.Zinc is an essential mineral that is naturally occurring found in foods and is also available as dietary supplement. How many atoms are in 16.5 g of Zinc? 2. Ammonia (NH3) is used for fertilizers and many other things. How many molecules of ammonia are present in 0.334 g of ammonia? Jens Martensson 133 Sample Problems B. Conversion between mass and moles 1. Ammonium Nitrate (NH4NO3) is a main component of explosive mixtures used in mining, quarrying, and civil construction. If an explosive contains 345.0 g of ammonium nitrate, how many mole of ammonium nitrate are present in the explosive? 2. Copper is used for the absorption and used of iron in the formation of haemoglobin. How many grams of Cu are present in 3.87 mol copper? Jens Martensson 134