* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Document
Transition state theory wikipedia , lookup
Organic chemistry wikipedia , lookup
Size-exclusion chromatography wikipedia , lookup
California Green Chemistry Initiative wikipedia , lookup
Bioorthogonal chemistry wikipedia , lookup
Chemistry: A Volatile History wikipedia , lookup
Isotopic labeling wikipedia , lookup
Nuclear chemistry wikipedia , lookup
Click chemistry wikipedia , lookup
Biochemistry wikipedia , lookup
Chemical thermodynamics wikipedia , lookup
Debye–Hückel equation wikipedia , lookup
Host–guest chemistry wikipedia , lookup
Inorganic chemistry wikipedia , lookup
Drug discovery wikipedia , lookup
Green chemistry wikipedia , lookup
Process chemistry wikipedia , lookup
Rate equation wikipedia , lookup
Analytical chemistry wikipedia , lookup
IUPAC nomenclature of inorganic chemistry 2005 wikipedia , lookup
History of molecular theory wikipedia , lookup
Computational chemistry wikipedia , lookup
Molecular dynamics wikipedia , lookup
History of chemistry wikipedia , lookup
Physical organic chemistry wikipedia , lookup
Gas chromatography–mass spectrometry wikipedia , lookup
CHAPTER 1 INTRODUCTION TO CHEMISTRY DEFINATION OF CHEMISTRY Chemistry is the branch of science that deals with the properties, composition and structure of matter. BRANCHES OF CHEMISTRY There are various branches of chemistry. The main branches of chemistry are PHYSICAL CHEMISTRY ORGANIC CHEMISTRY INORGANIC CHEMISTRY ANALYTICAL CHEMISTRY BIO CHEMISTRY INDUSTRIAL AND APPLIED CHEMISTRY NUCLEAR CHEMISTRY ENVIRONMENTAL CHEMISTRY POLYMERIC CHEMISTRY PHYSICAL CHEMISTRY It is the branch of chemistry that deals with the law and principle governing the combinations of atoms and molecules in chemical reactions ORGANIC CHEMISTRY It is the branch of chemistry that deals with carbon compounds with the exception of CO2, CO, metal carbonates, bicarbonates and carbides. Actually it is the chemistry of hydrocarbons and their derivatives most of the consumers products are organic in nature. INORGANIC CHEMISTRY It is the branch of chemistry that deals with the chemistry of elements and there compounds, generally obtained from non-living organisms i.e. e. from minerals. ANALYTICAL CHEMISTRY It is the branch of chemistry of that deals with the study of methods and techniques involve determining the kind, quality and quantity of various component in a given substance. BIO CHEMISTRY 1 It is the branch of chemistry that deals with the compounds living organisms I. e. plants and animals and there metabolism in the living body. INDUSTRIAL CHEMISTRY It is the branch of chemistry that deals with the study of different chemical processes involved in the chemical industries for the manufacture of synthetic products like glass, cement, paper, soda ach, fertilizers, medicines etc. NUCLEAR CHEMISTRY It is the branch of chemistry that deals with the study of changes occurring in the nuclei of atoms, accompanied by the emission of invisible radiations. ENVIRONMENTAL It is the branch of chemistry that deals with the study of the interaction of chemical materials and their effect on the environment of animals and plants. Personal hygiene, pollution and health hazards are important areas of environmental chemistry. POLYMERIC CHEMISTRY It is the branch of chemistry that deals with the study of polymerization and the products obtained through the process of polymerization such as plastics, synthetic fibers, papers etc. THE GREEK PERIOD GREEK PHLOSPHERS LIKE PLATO (347-428BC) They thought that all matter was derived four elements earth, air, fire and water. These elements have properties of there own such as hot dry cold and wet. According to them, fire was hot and dry earth was dry and cold water was cold, hot and wet and air was cold wet and hot. THE MUSLIUM PERIOD The Muslim period was from 600 to 1600AD. JABIR IBNE-HAIYAN (721-803AD) Jabir ibne-haiyan (721-803AD) generally known as the father of alchemy, invented experimental methods for the preparation of nitric acid, hydrochloric acid and white lead. He also developed methods for the extraction of metals from their ores and dyeing clothes. AL-RAZI (862-930AD) 2 Al-razi (862-930AD) was a physician, alchemist and a philosopher. He was an expert surgeon and was the first to use opium as an anesthesia. He divided the substances into living and non-living origins, which was later adopted by Berzelius, in 1608 to classify chemical compounds on the basic of their origins as organic and inorganic compounds. Al-razi prepared ethyl alcohol by the fermentation process. AL-BERUNI (973-1048AD) Al-beruni (97301048AD) contributed a lot in physics, metaphysics, mathematics, geography and history. In the filed of chemistry. He determined the density of different substances. IBNE-SINA (980-1037AD) Ibne-sina (980-1037AD) was famous for his contribution in the field of medicines, medicinal chemistry, philosophy, mathematics and astronomy. THE MODERN PERIOD ROBERT BOYLE (1627-1691AD) Robert Boyle (1627-1691AD) described affectionately as the father of modern chemistry, was the first to put forward the idea that chemistry should be regarded as systematic investigation of nature with the sole aim of promoting knowledge. J. BLACK (1728-1799) J. black (1728-1799) made a study of carbon dioxide. J. PRIESLLY (1733-1804) J. prieslly (1733-1804) discovered oxygen, sulphur dioxide and hydrogen chloride. SCHEELE (1742-1786) Scheele (1742-1786) discovered chlorine. CAVENDISH (1731-1810) Cavendish (1731-1810) discovered hydrogen. LAVOISIOR (1743-1794) Lavoisior (1743-1794) discovered that oxygen constituted about one-fifth of air. JHON DALTON (1766-1844) 3 John Dalton (1766-1844) made a great stride in chemistry with his atomic theory of matter. The idea of atoms and molecules become the established fact and the concept of atomic weight was also given by john Dalton. GAY-LUSSAC (1778-1850) AVOGADRO (1776-1856) DULANG (1785-1838) PETIT (1741-1820) Petit (1741-1820) determination of relative atomic and molecular masses of many substances. MEANWHILE J. J. BERZELLIUS (1779-1848) Meanwhile j. j. Berzelius (1779-1848) introduced the idea of symbols, formula and chemical equation to make the study more systematic. This was further enhanced. MENDELEEFF (1824-1907) Mendeleeff (1824-1907) who discovered the periodic arrangement of the elements. The ionic theory and the law of electrolysis were put forward. ARRHENIUS (1859-1927) M. FARADAY (1791-1867) M. faraday (1791-1867) respectively the work of. J. J. THOMSON (1856-1940) H. BECQUEREL (1852-1908) M. CURIE (1867-1934) NEIL BOHR (1885-1962) E. RUTHERFORD (1891-1937) E. Rutherford (1891-1937) led to the discoveries of structure of atom, radioactivity, there by opening the door of the present nuclear age. CHEMISTRY AND SOCIETY 4 There are three significant reasons to study chemistry. First chemistry has important practical application in the society. The development of life saving drugs in one and a complete list would touch upon most areas of modern technology. Second chemistry is an intellectual enterprise, a way of explaining our material world. Finally chemistry figures prominently in other fields, such as a biology in the advancement of medicines. Chemistry in every field is a useful intellectual tool for making important decisions. THE SCIENTIFIC APPROACH IN CHEMISTRY OBSERVATION, HYPOTHESIS, THEORY AND LAW Over the years science has developed through a series of discoveries which started off as observed natural phenomenon which had to be explained. This was done by using scientific method in a systematic manner. OSERVATION Observation is a basic tool to go forth for elaborating a phenomenon but it may vary from person to person according to his own skill of elaboration. Observation of a thing is one of the scientific approaches in chemistry. HYPOTHESIS This explanation; which is still only a trial idea is called hypothesis. It may or may not undergo a change as result further investigations and accumulation of more knowledge for facts. THEORY When the hypothesis is supported by a large amount of different types of observation and experiments, then it becomes a theory i.e. scientifically acceptable idea or principle to explain a phenomenon. SCIENTIFIC LAW A theory which is tested again and found to fit the facts and from which valid predictions may be made is then known as scientific law or principle. FILL IN THE BLANKS 1. The early Greeks believed that every thing in the universe was made up of four element earth, air, fire and water. 2. Al-razi divided chemical substances on the basic of their living and nonliving. 3. Organic chemistry is the branch of chemistry which deals with the carbon compounds. 4. Bio chemistry is the backbone of living organism 5 5. 6. 7. 8. PVC which is a plastic is the short name for poly vinyl chloride. Oxygen was discovered by lavoisior. The best disinfectant is scientific law. The periodic arrangement was the result of mendeleeff work. CHAPTER 2 CHEMICAL COMBINATION LAW OF CHEMICAL COMBINATION Chemistry deals with the matter and the change occurring in it chemists are particularly interested in these changes where one or more substances are changed in to quite different substances. They had found that these chemical changes are governed by some empirical law known as law of chemical combination. The laws of chemical combination are following. 1. The law of conservation of mass. 2. The law of constant composition or The law of definte proportion. 3. The law of multiple proportion. 4. The law of reciprocal proportion. THE LAW OF CONSERVATION OF MASS Mass is neither created nor destroyed during a chemical reaction or in any chemical reaction. The initial weight of reacting substances is equal to the final weight of the product. THE LAW OF CONSTANT COMPOSITION OR THE LAW OF DEFINTE PROPORTION Different samples of the same compound always contain the same element combined together in the same proportional by mass. THE LAW OF MULTIPLE PROPORTION If to element combine to from more that one compound. The masses of element that combine with a fixed mass of the other element are in the ratio of small whole number or simple multiple ratio FOR EXAMPLE. Carbon (C) forms two stable compounds with oxygen (O) namely carbon monoxide (CO) and carbon dioxide (CO2). 6 Compound Carbon monoxide(CO) Carbon dioxide (CO2) Mass of carbon (C) 12 12 Mass of oxygen (O) 16 32 Ratio of oxygen (O) 1 2 The different masses of oxygen 16 and 32 which combine with the fixed mass of c (12g) are in the ratio of [16:32], i.e. 1:2, which is simple whole number ratio and obeys. The law of multiple proportion. THE LAW OF RECIPROCAL PROPORTION When two different elements separately combine with the fixed mass of third element. The proportion in which they combine with one an other shall either it’s the same ratio or same multiple of it. This law was proposed by ritcher in 1972. EXAMPLE When two elements C and O separately combine with H to from methane (CH) and water (H O) respectively it is very clear, that in methane 3g of C combine with 1g of hydrogen and in water (H O) 8g of O combine with the same (fixed) mass i.e. (1g) of H now when C and O combine with each other to form carbon dioxide (CO), they do so in the same proportion i.e. 12:32 = 3:8 parts by mass. CO 12:32 i.e. 3:8 PRACTICAL VERIFICATION Landolt took the H-shaped tube and filled the two limbs ‘A’ and ‘B’ with silver nitrate (AgNO3) in limbs ‘A’ and hydrochloric Acid (HCL) in limb ‘B’. The tube was weight initially in a vertical position so that the solution should not inter wise after sealing the tube. The reactants were mixed by interring and shaking the tube. The tube was weighed after mixing the solution and the formation of white precipitate of silver chloride (Agcl). He observe the weight remain some AgNO3 + Hcl Agcl + HNO3 7 BERZELLIUS EXPERIMENT J.J. Berzelius (1779-1848) Berzelius heated log of lead (Pb) with various amounts of sulpher (S). He got exactly 11.56g of lead sulphide and the excess of sulpher was over when he used 18g of lead (Pb) with 1.56g of sulpher (S) he got exact 11.56g of lead sulphide (Pbs) and the 8g of lead (Pb) remained un used. 8 Q1. Empirical formula C4H4 and the molecular mass 104 find n (C = 12, H = 1) Data: Empirical formula = CH Molecular mass = 104 n =? As we know that n = M.mass . E. Formula Emperical formula C4H4 E. F of mass = 12 × 4 + 1 × 4 = 48 + 4 ² = 52 104 52 n=2 Ans. Q2. Empirical formula C2H2O2 and the molecular mass 104 find n (C = 12, H = 1, O = 16) Data: Empirical formula = CHO Molecular mass = 104 n =? As we know that n = Molecular Mass Empirical formula Empirical formula C2H2O2 Empirical formula of mass = 12 × 2 + 1 × 2 + 16 × 2 = 24 + 2 + 32 9 = 58 104 58 n= 1.79 Ans. Q3. 50 gram Na & H2O number of moles. Data: Na = 23 a. m. u. Given mass = 50 gm n =? As we know that Number of moles = given mass of substances Atomic mass or formula mass n = 50 23 n = 2.17 moles Ans. Data: HO = 18 a. m. u. Given mass = 50 gm n =? As we know that Number of moles = given mass of substances Atomic mass or formula mass n = 50 18 n = 2.77 moles Ans. Q4. 28 gram CO2 & C6H6 number of moles. 10 Data: CO2 = 44 a. m. u. Given mass = 28 n =? As we know that Number of moles = given mass of substances Atomic mass or formula mass n = 28 44 n = 0.63 moles Ans. Data: C6H6 = 78 Given mass = 28 n =? As we know that Number of moles = given mass of substances Atomic mass or formula mass n = 28 78 n = 0.35 moles Ans. Q5. 26 gram Al & CH4 number of moles (Al = 27) Data: Al = 27 Given mass = 26 n =? As we know that Number of moles = given mass of substances Atomic mass or formula mass n = 26 27 n = 0.96 moles Ans. Data: CH4 = 16 11 Given mass = 26 n =? As we know that Number of moles = given mass of substances Atomic mass or formula mass n = 26 16 n = 1.62 moles Ans. ATOMIC MASS Atomic mass is the average mass of naturally occurring isotopes which is compared to the mass of one atom of carbon – 12 a. m. u. ATOMIC MASS UNIT Atomic mass unit is defined as one-twelfth the mass of C-12 atom (the carbon atom that contains six protons and six neutrons). EMPERICAL FORMULA An empirical formula is simplest ratio of the atoms in a compound. EXAMPLE The molecular formula of benzene is C6H6. The ratio of carbon and hydrogen is 6:6 or 1:1. The empirical formula of benzene is CH. MOLECULAR FORMULA Molecular formula of an element or a compound shows the actual number of atoms present in the molecule of these substances. EXAMPLE Compounds Caron dioxide Sugar Glucose Hydrogen peroxide molecular formula CO2 C12H22O11 C6H12O6 H2O2 A molecular formula may be a simple whole number multiple of an empirical formula. Molecular formula = (Empirical formula) 12 n = Molecular formula Empirical formula MOLECULAR FORMULA MASS OR MOLECULAR MASS The sum of atomic masses of all atom present in the molecular formula of a substance or molecular is called molecular formula mass or molecular mass. EXAMPLE The atomic mass of carbon is 12 a. m. u. and oxygen is 16. C = 1 × 12 = 12 a. m. u. O = 2 × 16 = 32 a. m. u. Molecular formula mass of CO2 = 44 a. m. u. FORMULA MASS The sum of atomic masses of atom in formula unit of substance is called formula mass. EXAMPLE The atomic mass of sodium Na is 23 a. m. u. and the atomic mass of chlorine 35.5 a.m.u. Sodium = Na = 1 × 23 = 23 a. m. u. Chlorine = Cl = 1 × 35.5 = 35.5 a. m. u. Formula mass of NaCl is = 58.5 a. m. u. MOLAR MASS The relative molecular mass of a substance expressed in gram is called as molar mass. It has fixed unit. EXAMPLE Molecular mass of carbon is 12 a. m. u. and therefore the molar mass of carbon would be 12.g. MOLE The atomic mass, molecular mass and formula mass of a substance expressed in gram is called mole. EXAMPLE One moles of carbon (C) = 12g One moles of magnesium (mg) = 24g One moles of water (H2O) = 18g The number of moles can be calculated by following formula. 13 Number of moles = given mass of substance . Atomic mass or M. mass or F. mass AVAGADRO’S NUMBER The number of particles, atoms, ions molecules in one mole of a substance is called Avogadro’s number. It denoted by ‘‘NA’’ its value is 6.02×10²³. EXAMPLE One mole of carbon (C) = 12g = 6.02×10²³ atoms One mole of magnesium (mg) = 24g = 6.02×10²³ atoms One mole of water (H2O) = 18g = 6.02×10²³ atoms. Q1. Calculate the number of molecules in 9g of CO2. Data: Number of molecules? Mass of substance = 9g Molecular mass of CO2 44 As we know that no of molecules = NA × mass of substance Atomic mass no of molecules = 6.02 × 10²³ × 9 44 no of molecules = 54.18 × 10²³ 44 No of molecules = 1.231 × 10²³ Ans. Q2. Calculate the mass of one atom of carbon in gram. Data: According to Avogadro number. 14 C = 12g 6.02 × 10²³ atomic of C = 12 As we know that 1 atom of c = given mass NA = 12 6.02 × 10²³ 1 atom of C = 2.993gm Ans. Q3. Calculate the mass of one molecule of water (H2O) in gram. Data: According to Avogadro number. H O = 18gm 1 molecule of H2O = 18 = 6.02 × 10²³ As we know that 1 molecule of H O = given mass NA = 18 . 6.02 × 10²³ 1 molecule of H O = 2.99gm Ans. Q4. Calculate the number of molecules in 6gm of CO2. 15 Data: Number of molecule =? Mass of substance = 6gm Molecular mass of CO2 = 44 As we know that Number of molecules = NA mass of substance Atomic mass Number of molecules = 6.02 × 10²³ × 6 44 Number of molecules = 36.14 × 10²³ 44 Number of molecules = 0.82 Ans. CHEMICAL CHANGE Any change which alters the composition of a substance is called chemical change. FOR EXAMPLE Rusting of iron is a chemical change. CHEMICAL REACTION The process of change in the composition of one or substance in which one pr more new substance are formed with the result of chemical change called chemical reaction. TYPES OF CHEMICAL REACTIONS The important types of chemical reactions are following. 1. Decomposition reaction 2. Addition reaction or synthesis 3. Single displacement reaction 4. Double displacement reaction 5. Combustion reaction 6. Neutralization 7. Hydrolysis 16 DECOMPOSITIOM REACTION A reaction in which a chemical substance breaks down to from two or more simple substance is called decomposition reaction. EXAMPLE Calcium carbonate decomposes into calcium oxide and carbon dioxide on heating CaCO3 (s) heat Cao (s) + CO2 (g) Zinc nitrate decomposes in zinc oxide, nitrogen per oxide and oxygen on heating. 2Zn (Na3)2 (s) heat 2Zno (s) + 4NO2 (g) ADDITION REACTION OR COMBINATION REACTION OR SYNTHESIS A chemical process of the composition of two or more substance in the from of a single substance in called addition reaction, combination reaction or synthesis. EXAMPLE Calcium oxide react with carbon dioxide to from calcium carbonate. CaO (s) + CO2 (g) heat CaCO3 (s) SINGLE DISPLACEMENT REACTION A chemical reaction in which an atom or group of atom is replaced by another atom or group of atom is called single displacement reaction. EXAMPLE Zinc replaces hydrogen in hydrogen chloride (HCl) to give zinc chloride. Zn (s) + HCl (aq) ZnCl2 (s) +H2 (g) 17 DOUBLE DISPLACEMENT REACTION A chemical process in which two compounds exchange their partners or group of atom, so that new compounds are formed called double displacement reaction. EXAMPLE When sodium hydroxide reacts with nitric acid (HNO3) they exchange their partners to from sodium nitric and water. NaOH (aq) + HNO3 (aq) NaNO3 (s) + H2O (l) CUMBUSTION REACTION A reaction in which substance react with either free oxygen or oxygen of air, with the rapid release of heat and flame is called combustion reaction. EXAMPLE When sulpher burn in air to forms sulpher dioxide. S (s) + O2 SO2 (g) NEUTRALIZATION A chemical reaction of an acid with a base which gives a salt and water is called neutralization. EXAMPLE When nitric acid react potassium hydroxide then potassium nitrate and water are formed HNO3 (aq) + KOH (aq) KNO3 (aq) + H2O (l) HYDROLYSIS A chemical reaction of an acid and base which gives its constituents acid and base called hydrolysis. EXAMPLE 18 When sodium carbonate reacts with water it forms sodium hydroxide and carbonic acid. Na2CO3(s) + 2H2O (l) 2NaOH (aq) + H2CO3 (aq) BALANCING EQUATION 1. C + O2 CO REACTANTS C (2) PRODUCTS C (2) O (2) O (2) BALANCING EQUATION 2C + O2 2CO 2. CO + O2 CO2 19 REACTANTS C (2) PRODUCTS C (2) O (4) O (4) BALANCING EQUATION 2CO + O2 2CO2 3. KNO3 KNO2 + O2 REACTANTS K (2) PRODUCTS K (2) N (2) N (2) O (6) O (6) BALANCING EQUATION 2KNO3 O2 4. NaHCO3 2KNO2 + Na2CO3 + H2O + CO2 REACTANTS Na (2) H (2) C (2) O (6) PRODUCTS Na (2) H (2) C (2) O (6) BALANCING EQUATION 2NaHCO3 CO2 5. CaCO3 + HCl Na2 CO3 + H2O + CaCl2 + H2O + CO2 20 REACTANTS Ca (1) C (1) O (3) H (2) Cl (2) PRODUCTS Ca (1) C (1) O (3) H (2) Cl (2) BALANCING EQUATION CaCO3 + 2HCl CO2 6. NH3 + O2 CaCl2 + H2O + NO + H2O REACTANTS N (4) H (12) O (10) PRODUCTS N (4) H (12) O (10) BALANCING EQUATION 4NH3 + 5O2 +6HO2 4NO CHEMICAL EQUATION A chemical equation is a short hand way of representing a chemical reaction. Following steps are taken in writing a chemical equation. 1. Reactants are written on the left hand side of chemical equation while products are written on the right. 2. Reactant and product are connected by an arrow. 3. Balance the equation .balance equation have the same kind and number of atoms on each side. 4. Indicate physical state of the reactants and product we use (s) for solid, (l) for liquid, (g) for gas and (aq) for aqueous. BALANCING EQUATION 21 Most chemical equations can be balancing by inspection method, that is, by trial and error method, with the experience, you should be able to balance any equation quickly. In general we can balance the equation by the following steps. 1. Write correct formula for the reactant on the left and for the product on the right with on arrow between. 2. Put a plus sing between them if two or more reactants or products are present. 3. Count the number of atom of each element in the reactants and products. 4. Balance one element at a time using coefficient. 5. Check the coefficient. They most being their lowest possible ratios. EXAMPLE OF BALANCING EQUATION When hydrogen and oxygen react, the product is water. We write balance equation fro the reaction. Reactants and products are know we can write a skeleton equation H2 (g) + O2 (g) H2O (l) KNO3 KNO3 + O2 REACTANTS K (2) PRODUCTS K (2) N (2) N (2) O (6) O (6) BALANCING EQUATION 2KNO3 O2 2KNO2 + DENSITY The mass of a substance per unit volume is called density. Its unit is kilogram per cubic meter (kgm ³). FORMULA Density = mass Volume ATOM The smallest particle of an element which represents the properties of the element is called atom. 22 PHYSICAL PROPERTIES 1. Properties of a substance which do not deals with its ability to undergo chemical change are called physical change. 2. They are related to the physical state of matter. 3. These properties are the characteristics of a substance. CHEMICAL PROPERTIES 1. Processes of a substance which indicate its ability to undergo chemical change are called chemical properties. 2. The are related to the chemical change of substance. 3. These properties explain the chemical behavior of a substance. FILL IN THE BLANKS 1. 18 gram of H2O contains 6.02 ×10²³ molecules. 2. A change which alters the composition of a substance is called chemical change. 3. A reaction, in which a chemical substance breaks down to form two or more similar substance, is called decomposition reaction. 4. The reaction of NaCl with AgNO3 is givens as NaCl (aq) + AgNO3 (aq) AgCl (s) NaNO3 (aq) Is the reaction of the type double displacement reaction. 5. Addition reaction is the reaction in which two or more substances combine together to form a single substance. 6. A reaction in which a substance burns in oxygen to produce heat and flame is called combustion reaction. 7. Chemical reaction is the short hand method to describing a chemical reaction. 8. The reaction Zn + 2HCl ZnCl2 + H2 (g) is the single displacement reaction. 9. When metals react with acids or water then produce hydrogen gas. TICK THE CORRECT ANSWER 1. Mass is neither created nor destroyed during a chemical change, is the statement of: law if conservation of mass. a: Law of conservation of mass. b: Law of definite proportion. c: L aw of multiple proportion. d: Law of reciprocal proportion. 23 1. A given compound always contains exactly the same proportion of element, by mass, is the statement of: law of definite proportion. a: Law of conservation of mass. b: Law of definite proportion. c: L aw of multiple proportion. d: Law of reciprocal proportion. 2. The average mass of natural mixture of isotopes, which is compared to the of one atom of C-12 a. m. u, is called: atomic mass. a: Atomic mass b: Mass number c: Atomic number d: None of these 3. A formula that gives only the relative number of each type of atom in a molecular is called: empirical formula. a: Empirical formula b: Molecular formula c: Molecular mass d: Formula mass 4. A formula that indicates actual number and type of atoms in a molecule is called: molecular formula a: Empirical formula b: Molecular formula c: Molecular mass d: Formula mass 5. The sum of atomic masses of all atoms in a molecule is called: molecular mass. a: Empirical formula b: Molecular formula c: Molecular mass d: Formula mass 7. The sum of atomic masses of all atoms in a formula unit of substance is called: Formula mass. a: Empirical formula b: Molecular formula c: Molecular mass d: Formula mass 8. The mass of (1) mole of substance expressed in grams is called: molar mass. a: Empirical formula b: Molecular formula c: Molecular mass d: Molar mass 9. 44 a. m. u. of CO2 is equal to molecular mass. a: Molar mass b: Atomic mass c: Molecular mass d: Mass number 10. 5 moles of H2O are equal to 90gm. 24 a: 80g c: 100g b: 90g d: 90 a.m. u. 25