Title Chemistry Ultra HD Maps.pdf ✅

m One atomic mass unit (amu) is defined as a mass exactly equal to one-twelfth of the mass of one –24 C-12 atom, 1 amu = 1.66056 × 10 g. m At present amu has been replaced by unified mass (u) m Average atomic mass can be computed when we take into account the existence of isotopes and their relative abundance. m Molecular mass is the sum of atomic masses of the elements present in a molecule. m Formula mass is used instead of molecular mass for ionic solids as in solid state they do not exist as a single entity. m Empirical formula represents the simplest whole number ratio of various atoms present in a compound, whereas, the molecular formula shows exact number of different types of atoms present in a molecule of a compound. m Important points for rounding off the numbers. If the rightmost digit to be removed is more than 5, the preceding number is increased by one. l l If the rightmost digit is less than 5, the preceding number is not changed. l If the rightmost digit is 5 then preceding number increased by 1 only if it is an odd number. m Method used to interconversion of unit is known as dimensional analysis, unit factor method. m Law of conservation of mass conclude that in all physical and chemical changes, there is no net change in mass during the change. m Law of definite proportions/composition stated that a given compound always contains exactly the same proportion of elements by weight. m Law of multiple proportions stated that, if two elements can combine to form more than one compound, the masses of one element that combine with a fixed mass of other element are in the ratio of small whole number. m Gay Lussac's law of gaseous volume : When gases combine or are produced in a chemical reaction they do so in a simple ratio by volume, provided all gases are at same temperature and pressure. m Avogadro's law proposed that equal volumes of all gases at same temperature and pressure should contain equal number of molecules. m Dalton's Atomic Theory proposed to following points l Matter consists of indivisible atoms. l All atoms of a given element have indentical properties, including identical mass, atoms of different elements differ in mass l Compounds are formed when atoms of different elements combine in a fixed ratio Chemical reactions involve l reorganisation of atoms. These are neither created nor destroyed in a chemical reaction. 4 LAWS OF CHEMICAL COMBINATION m Stoichiometry deals with calculation of masses (sometime volume) of the reactants and products involved in a chemical reaction. m Reactant, which gets consumed first, limits the amount of product formed is called limiting reagent. m A majority of reactions are carried out in solutions. The concentration of a solution can be expressed in following ways. m Mass percent = Mass of solute × 100 / (Mass of solution) m Mole fraction of solute = No. of moles of solute/No. of moles of solution m Molarity (M) = No. of moles of solute / Volume of solution in litres For dilution of solutions, M V = M V l 1 1 2 2 m Molality (m) = No. of moles of solute/Mass of solvent in kg. 7 STOICHIOMETRY AND STOICHIOMETRIC CALCULATIONS 5 ATOMIC AND MOLECULAR MASS m Mole (Symbol, mol) is seventh base quantity for amount of a substance. m 23 One mole contains exactly 6.02214076 × 10 elementary entities. This number is the fixed numerical value of the Avogadro's constant (N ). A m The mass of one mole of a substance in grams is called its molar mass. m Mass% of an element = Mass of that element in the compound × 100 / Molar mass of the compound. 6 MOLE CONCEPT AND MOLAR MASSES 2 Some Basic Concepts of Chemistry NCERT Maps -
NCERT Maps Some Basic Concepts of Chemistry 3 1. Incorrect boiling point of water is [NCERT Pg. 10] (1) 373 K (2) 100°C (3) 212°F (4) 98.6°F 2. Number of significant digits in 0.200 g is [NCERT Pg. 12] (1) 1 (2) 2 (3) 3 (4) 4 3. Law of multiple proportions is not valid for the pair of [NCERT Pg. 15] (1) H2O and H2O2 (2) CO and CO2 (3) CH4 and CO2 (4) CH4 and C2H6 4. Select the incorrect statement regarding Dalton’s atomic theory [NCERT Pg. 16] (1) Matter consists of indivisible atoms (2) Atoms of given element have identical properties (3) Compounds are formed when atoms of different elements combined in a fixed ratio (4) Atoms are created or destroyed in a chemical reactions 5. An element has two isotopes having atomic mass 10 and 15 u respectively. If the % abundance of lighter isotope is 80% then the average atomic mass of the element is [NCERT Pg. 17] (1) 9 u (2) 11 u (3) 12 u (4) 14 u 6. Formula mass is used instead of molecular mass in the case of [NCERT Pg. 17] (1) H2O (2) NaCl (3) He (4) H2 7. 88 g of CO2 contains (NA = Avogadro’s No.) [NCERT Pg. 18] (1) NA molecules (2) 2NA molecules (3) 0.5 NA molecules (4) 4NA molecules 8. In which molecule, mass % of both elements in the molecule are equal? [NCERT Pg. 19] (1) CO (2) SO2 (3) NH3 (4) H2O2 9. A hydrocarbon contains 80% carbon by mass. The empirical formula of the hydrocarbon is [NCERT Pg. 19] (1) CH (2) CH2 (3) CH3 (4) CH4 10. Mole(s) of CO2 gas obtained at STP, when 32g CH4 reacted with 32 g of oxygen is [NCERT Pg. 20] (1) 0.5 (2) 1 (3) 2 (4) 3 11. Mass of one CO molecule in gram is [NCERT Pg. 18] (1) 4.65 × 10–23 (2) 1.66 × 10–24 (3) 3 × 10–24 (4) 6.22 × 10–23 12. If 2 mol of N2 and 3 mol of H2 mixed together to produce NH3 then select the correct option. [NCERT Pg. 22] (1) N2 is limiting reagent (2) 1 mole of NH3 will be formed (3) H2 is limiting reagent (4) N2 and H2 both are limiting reagents 13. The aqueous solution contains 2g of solute in 18 g solution. The mass% of solute is [NCERT Pg. 23] (1) 11.1% (2) 10% (3) 12.5% (4) 80% 14. A gaseous mixture of CH4 and O2 contains equal masses of both. The mole fraction of CH4 in the mixture is [NCERT Pg. 23] (1) 1 2 (2) 1 3 (3) 2 3 (4) 1 4 15. In order to prepare 500 mL, 0.2 M NaOH solution, the mole(s) of NaOH required is [NCERT Pg. 23] (1) 0.1 (2) 0.2 (3) 1 (4) 2 -
Some Basic Concepts of Chemistry NCERT Maps 4 16. 2M, 2L aqueous HCl solution is mixed with 3L H2O, the molarity of resultant solution is [NCERT Pg. 23] (1) 1.34 M (2) 0.4 M (3) 0.8 M (4) 1 M 17. 58.5 g of NaCl is added in 2500 g of water. The molality of the solution formed is [NCERT Pg. 23] (1) 0.2 m (2) 0.4 m (3) 0.8 m (4) 1 m 18. The density of 1 M solution of compound A is 1.12 g mL–1. The molality of the solution is (Molar mass of A = 120 g mol–1) [NCERT Pg. 23] (1) 0.55 m (2) 0.75 m (3) 1 m (4) 1.2 m 19. Mole fraction of solute in 1 molal aqueous NaOH solution is [NCERT Pg. 28] (1) 1 (2) 0.5 (3) 1 55.55 (4) 1 56.55 20. 0.0014 can be written in scientific notation as [NCERT Pg. 11] (1) 0.14 × 10–2 (2) 1.4 × 10–3 (3) 14 × 10–4 (4) 140 × 10–3 1. _____ refers to the closeness of various measurements for the same quantity. [NCERT Pg. 13] 2. According to law of definite proportions, a given compound always contains same elements combined together in the same proportion by _____ [NCERT Pg. 16] 3. 12C and 14C are _____ of carbon. [NCERT Pg. 16] 4. 1 amu is defined as mass exactly equal to _____ of the mass of one carbon-12 atom. [NCERT Pg. 17] 5. 6.022 × 1023 is known as _____ [NCERT Pg. 18] 6. 5 moles of H2SO4 contains_____ moles of atoms. [NCERT Pg. 18] 7. Empirical formula of CH3COOH is _____ [NCERT Pg. 19] 8. The reactant, which gets consumed first, limits the amount of product formed is known as _____ [NCERT Pg. 21] 9. Number of moles of _____ after and before dilution remained the same. [NCERT Pg. 24] 10. 15 ppm means 15 g of solute in _____ g of solution. [NCERT Pg. 26] 11. 12.7106 can be rounded up in three significant figures as _____ [NCERT Pg. 27] 12. 1 dm3 is equal _____ L. [NCERT Pg. 27] 13. 1 micro is equal to _____ [NCERT Pg. 9] 14. Counting the number of object has _____ significant figures. [NCERT Pg. 13] 15. Volume of 56 g CO gas at STP is _____ [NCERT Pg. 28] 16. For a binary solution, mole fraction of solute is 0.2 then mole fraction of solvent is_____ [NCERT Pg. 23] 17. Concentration term which changes with temperature is _____ [NCERT Pg. 23] 18. 1 mol of C3H8 for complete combustion requires _____ mol of O2 [NCERT Pg. 21] 19. Two volumes of hydrogen react with one volume of oxygen to give _____ of water vapours. [NCERT Pg. 16] 20. For the multiplication of 3.7 and 1.384, the result should not have more than _____ significant figures. [NCERT Pg. 13]    -