0.3 mole of aluminium (Atomic mass of Al = 27). For one mole of Al3+ ion, three moles of electrons are to be lost. $$_{6} \mathrm{Cl}^{13},_{7} \mathrm{N}^{14}$$, iii. = 2.77 Ã 1021 atoms, Question 12. Hint: Answer: Which one of the following is an example of a polyatomic molecule? Correct statement: Atom is the smallest particle that takes part in a chemical reaction. The _____ is useful to determine the empirical formula and molecular formula. Answer: Number of moles = $$\frac{\text { Mass }}{\text { atomic mass }}=\frac{1.4}{7}$$ = 0.2 mole of lithium. The density of water at room temperature is 1.0 g/mL. A sample of ammonia weighs 3.00 g. What mass of sulphur trioxide contains the same number of molecules as are in 3.00 g ammonia? (c) Both (A) and (R) are correct. (d) 1 g of C – 12 Answer: Question 27. Correct statement: The number of atoms present in one molecule of an element is called the atomicity of an element. Question 3. Atomic mass of sulphur = 32 (ii) A is correct, R is wrong. Number of moles = $$\frac{\text { No. (i) 1 mole of oxygen contains 6.022 Ã 1023 atoms Question 32. Standard atomic weight. We know that one atom of carbon has 6 electrons and one atom of chlorine has 17 electrons. Answer: Question 16. Answer: (c) C – 12, Question 8. (i) (A) and (R) are correct. (b) triatomic Question 7. Calculate the number of magnesium atoms in 20 g of chlorophyll. What is homo atomic molecule? 40 g of calcium = 1 mol Answer: Question 1. Eg: Glucose C6H12O6 C : H : O = 6 : 12 : 6 or 1 : 2 : 1. (iii) (A) is wrong (R) is correct, Question 14. Which has the highest number of molecules? Calculate the number of molecules in 11.2 litre of CO2 at S.T.P The atoms of the different element with the same mass number (A) but different atomic number (Z) are called isobars. = 120 + 188 Example 1. Answer: (d) (A) is wrong but (R) is correct. Question 19. Answer: (b) Molecular mass of C2H5OH = 2 Ã 12 + 5 Ã 1 + 1 Ã 16 + 1 True or False: (If false give the correct statement). (a) 6.023 Ã 1023 Number of molecules = 0.2232 Ã 6.023 Ã 1023 = 1.344 Ã 1023 molecules. (d) 16.2 %. (i) H2O The molecular formula of gases can be derived using Avogadroâs law. Question 33. (a) 0.125 mole 1 molecule of oxygen (O2) = 2 atoms of oxygen Hetero triatomic. (b) 6.023 Ã 10-23 Question 13. 19 k happy customers 9.5 out of 10 satisfaction rate 527 writers active Basic features. 98 g of sulphuric acid = 1 mol 32 g of 02 contains 6.02 2 Ã 1023 molecules (b) 23 g The volume occupied by 4.4 g of CO2 at S.T.P is _____. (c) allotropes (a) O Number of moles = \(\frac{\text { Number of molecules of water }}{\text { Avogadro’s number }}$$ Question 3. 1.12 Ã 10-7 cc contains = $$\frac{6.023 \times 10^{23}}{22400} \times 1.12 \times 10^{-7}$$ Question 16. (d) relative atomic mass. Avogadro’s law states that 1 mole of any substance contains 6.023 Ã 1023 molecules. Answer: One mole is defined as the amount of the substance which contains 6.023 Ã 1023 number of particles. Carbon C – 12. Gram molecular mass of 3 moles of Cl2 Answer: (c) 1 g of H2 Answer: 10 : 3 : 12, (b) MgCl2 6.023 Ã 1023 CO2 molecules has the mass = 44 g For example, when ice melts into water, the mass of ice equals to the mass of water, i.e., the mass is conserved. Differentiate between the actual mass of a molecule and gram molecular mass. Reason (R): Atom is the ultimate particle of an element which may or may not have an independent existence. (ii) How many moles of gas molecules are obtained from 1 mole of nitroglycerine? (i) H2O What would be the difference in the composition of carbon dioxide in the two cases? State Avogadro hypothesis (or) Avogadro’s Law. [NCERTExemplar] Therefore, one molecule of CCl4 will contain 6 + (4 Ã 17) = 74 electrons. of moles of Ammonia = $$\frac { 5.1 }{ 17 }$$ = 0.3 moles of ammonia, No. $$\text { Mole }=\frac{\text { Mass }}{\text { Atomic mass }}=\frac{16}{40}=\frac{8{}}{20}$$ $$=\frac{4}{10}=0.4 \mathrm{mole}$$. The volume occupied by 1 mole of a diatomic gas at S.T.P is _____. Mass of 6.023 Ã 1023 atoms of He = 0.004 kg. }}{\text { Molar volume at } \mathrm{S} . (i) 1 mole of chlorine molecule, Cl2 The mass of three moles of electrons = 3 Ã (9.1 Ã 10-28) Ã 6.0 2 2 Ã 1023 g = 18.9576 + 2.5 + 2.8626 Number of moles of CCl4 = $$\frac{\text { Mass of } \mathrm{CCl}_{4}}{\text { Molecular mass of } \mathrm{CCl}_{4}}=\frac{15.4 \mathrm{g}}{154 \mathrm{g}}$$ Mass of carbon atoms carried by Raunak = (5 Ã 12) g = 60 g Answer: The percentage composition of a compound represents the mass of each element present in 100 g of the compound. (c) (A) is correct but (R) is wrong = 6.022 Ã 1022 molecules of CCl4 (c) 1 / 12th of the mass of a C – 12 atom How many C2H6 molecules does the sample of gas contain? Calculate the % of oxygen in Al2(SO4)3. Answer: Question 1. Molar mass of Al3+ = (27 – 0.00164) g mol-1 Question 11. 0.5 mole of oxygen gas = 6.022 Ã 1023 Ã 0.5 molecules Water is a _____ molecule. Answer: False. Answer: 40 : 12 : 16 Ã 3 = 1.51 Ã 1023 CO2 molecules. True. The atomicity of H2SO4 is ______. â´ 0.1764 moles weigh = 80 Ã 0.1764 g Calculate the number of aluminium ions (Al3+) in 0.056 g of alumina (Al2O3). How many molecules are there in a drop of water if its volume is 0.05 mL? Question 18. (k) He (a) Both (A) and (R) are correct Deriving the Number of Atoms and Molecules from the Mass of a Compound A packet of an artificial sweetener contains 40.0 mg of saccharin (C 7 H 5 NO 3 S), which has the structural formula: Given that saccharin has a molar mass of 183.18 g/mol, how many saccharin molecules are in a 40.0-mg (0.0400-g) sample of saccharin? The number of atoms present in the molecule is called atomicity. Answer: The Earth is 2400 times heavier than one mole of screws. Answer: Question 4. Calculate the number of molecules in it. Question 28. Question 32. Calculate the mass of glucose necessary to prepare a 500 mL pouch of D5W. âµ Equal moles contains equal number of molecules. Question 15. (a) isotopes Question 9. of moles Ã molecular mass The molar mass of CO2 is 42 g? What is its use? In photosynthesis, 6 molecules of carbon dioxide combine with an equal number of water molecules through a complex series of reactions to give a molecule of glucose having a molecular formula C6H12O6. Mass of 2 moles of NaHCO3 = 84 Ã 2 = 168 g. (iii) Number of moles of CO2 in this equation = 1 mole. (b) 3.011 Ã 1023 One mole, (ii) Calculate the gram molecular mass of calcium carbonate involved in this reaction. (a) 12 amu Mass % of Hydrogen = $$\frac{2}{18} \times 100$$ = 11.11 % Question 31. Actual mass of a molecule is obtained by dividing the molar mass by Avogadroâs number whereas gram molecular mass represents the molecular mass expressed in grams, i.e., it is the mass of 1 mole of molecules, i.e., Avogadroâs number of molecules. The number of moles in 5 grams of Calcium is _____. Ozone (O3). (or) The volume occupied by 14 g of Nitrogen gas is 22.4 litres. = 30.115 Ã 1023 (O = 16, Ca = 40, S = 32) is _____. Answer: Assertion (A): The atomicity of ozone is three. False. (Atomic mass: Al – 12, O – 16, S – 32) Question 1. Answer: Gram molar mass of CO2 = (12 Ã 1) + (16 Ã 2) = 12 + 32 Mg : Cl Ã 2 (d) PCl5. 18 g of water contains 6.023 Ã 1023 water molecules. Assertion (A): $$_{1} \mathrm{H}^{1}, \quad_{1} \mathrm{H}^{2},_{1} \mathrm{H}^{3}$$ are the isotopes of hydrogen. Answer: (R) explain (A), Question 12. (Atomic mass of C = 12, H = 1, N = 14, O = 16) (a) Both (A) and (R) are correct, Question 10. Correct statement: O2, N2, H2, Cl2, Br2, F2, I2Â are homo diatomic molecules. Question 3. It is equal to 6.023 Ã 1023 (NA). (a) 27 Question 3. Answer: (d) 22 g Solution: Question 6. \mathrm{T.P}}{\text { Molar volume } \mathrm{SO}_{2} \text { at } \mathrm{S} . Calculate the number of moles in: Calculate the number of ions obtained from CaCl2 when 222 g of it is dissolved in water. Vapour density (V.D.) 1 mole of SO3 weighs 80 g (ii) 1 g atom of Ag = Gram atomic mass of Ag = 108 g Answer: Question 2. We know that Avogadro number is 6.022 Ã 1023 (a) 1 g of CO2 (d) $$\frac { 1 }{ 4 }$$ mole. (c) Tritium [Given that atomic mass of Ca = 40 u, Avogadro No. Ignore sun 3. plant alone = 0 1. (d) 8 Mass % of an element = $$\frac{\text { Mass of that element in the compound }}{\text { Molar mass of the compound }} \times 100$$ Answer: Define the Avogadro number. Calculate the number of atoms in each of the following: (c) (ii) and (iii) Calculate the formula mass of sodium carbonate (Na 2 CO 3.10H 2 O). An atom of one element can be transmuted into an atom of other element is known as artificial transmutation. Question 26. Define Vapour density. Answer: (b) 3.011 Ã 1023 (a) NaOH (a) 5 moles of CO2 and 5 moles of H20 do not have the same mass. Answer: 6.022 Ã 1022 molecules of oxygen = 1 mol Ã $$\frac{6.022 \times 10^{22}}{6.022 \times 10^{23}}$$ = 0.1 mol. (b) 11 $$\begin{array}{l}{\% \text { of } \mathrm{S} \text { in } \mathrm{H}_{2} \mathrm{SO}_{4}=\frac{\text { Mass of sulphur }}{\text { Molar mass of } \mathrm{H}_{2} \mathrm{SO}_{4}} \times 100} \\ {\% \text { of } \mathrm{S} \text { in } \mathrm{H}_{2} \mathrm{SO}_{4}=\frac{32}{98} \times 100}\end{array}$$ Answer: (c) (A) is correct but (R) is wrong. â 11 – x = 10.804 amu Assertion: Atomic mass of aluminium is 27 One atomic mass unit is a mass unit equal to exactly one- twelfth (1/12th) the mass of one atom of carbon-12. â -x = 10.804 – 11 (a) 12 g of C – 12. (c) 24.011 amu (a) 22.4 L A flask P contains 0.5 moles of oxygen gas. of atoms }}{\text { Avogadro number }}} \\ {=\frac{12.046 \times 10^{22}}{6.023 \times 10^{23}}=2 \times 10^{-1}} \\ {=0.2 \text { mole. Let the fraction of relative abundance of B – 10 = x Reason (R): The subatomic particles protons, electrons and neutrons were discovered. So, answer (c) is correct. Number of molecules of CO2 = Number of moles of CO2 Ã Avogadroâs number Percentage abundance of B – 10 = 19.6 % Question 4. Answer: Answer: (b) 6.023 Ã 10-23 Question 16. of moles Ã atomic mass Question 1. (d) 3.011 Ã 1024 â´ 0.1 mole of carbon atoms contains = 6.022 Ã 1023 Ã 0.1 atoms (c) $$\frac { 1 }{ 2 }$$th of the mass of a C – 12 atom = 62 u Question 2. When ammonia reacts with hydrogen chloride gas, it produces white fumes of ammonium chloride. = 36.132 Ã 1023 Answer: (c) mono atomic Atoms of different elements having the same number of neutrons but a different atomic number and different mass number are called _____. Computing Molecular Mass for a Covalent Compound Ibuprofen, C 13 H 18 O 2, is a covalent compound and the active ingredient in several popular nonprescription pain medications, such as Advil and Motrin.What is the molecular mass (amu) for this compound? Answer: $$\begin{array}{l}{\text { Number of moles of } \mathrm{CO}_{2}=\frac{\text { Given volume at S.T.P }}{\text { Molar volume at S.T.P }}} \\ {\qquad 2.5 \text { mole of } \mathrm{CO}_{2}=\frac{\text { Volume of } \mathrm{CO}_{2} \text { at } \mathrm{S} . Mass = Mole Ã Molecular mass = 0.5 Ã 18 = 9 g. Question 55. Water is an example of Hetero triatomic molecule. = 6.022 Ã 1023 atoms of hydrogen, (c) 1 molecule of water contains 1 atom of oxygen Question 1. (v) 1 mole of Ca = 40 g = 6.02 Ã 1023 atoms of Ca Mass of 2 moles of water = 18 Ã 2 = 36 g. (ii) 20 moles of water (a) Nitroglycerine Number of moles = \(\frac{\text { S.T.P. Question 39. = 1.51 Ã 1023 molecules, (c) 1 mole of carbon atoms contains 6.022 Ã 1023 atoms What are the differences between atoms and molecules? Answer: An aluminium atom needs to lose three electrons to become an ion. Question 30. = 3.011 Ã 1023 molecules, (b) 1 molecule of water contains 2 atoms of hydrogen 1 mole of CCl4 = 6.02 2 Ã 1023 molecules of CCl4 (b) 44 g Molecular mass of NaOH = 23 + 16 + 1 = 40 g. (iv) NO2 Answer: Molecular mass of SO2 = 32 + (16 Ã 2) = 32 + 32 = 64 Calcium carbonate: CaCO3 (c) 20.60 Prompt Delivery and 100% Money-Back-Guarantee. 1 mole of oxygen gas = 6.022 Ã 1023 molecules Give three significance of mole. (b) 1 g of N2 Answer: Question 56. Answer: = 6.613 Ã 1020 ions of Al3+, Question 3. Number of moles of H2 = \(\frac{6}{22.4}$$ = 0.2678 moles Answer: of moles of SO2 = $$\frac{GivenMass}{Mol.Mass}$$ The mass number is the sum of the number of protons and neutrons in an atom. (a) V â $$\frac{1}{n}$$ 0.25 = mass / 18 (b) isomers (b) 2, Question 7. A molecule is a combination of two or more atoms held together by _____. Mass of one atom = $$\frac{1}{6.022 \times 10^{23}}$$g (i) 3.011 Ã 1023 number of oxygen atoms. 2 moles of CaCl2 would give 3 Ã 2 = 6 moles of ions. [NCERT Exemplar] Answer: (b) $$_{18} \mathrm{Ar}^{40},_{20} \mathrm{Ca}^{40}$$ Calculate the number of molecules in 11 g of CO2. It is denoted as Ar. Law of conservation of mass states that mass can neither be created nor destroyed in a chemical reaction. A silver ornament of mass âmâ gram is polished with gold equivalent to 1% of the mass of silver. or, 3 : 5, Question 5. Question 3. Correct statement: The volume occupied by 14 g of Nitrogen gas is 11.2 litres. Question 16. Question 5. Which one of the two is heavier and by how many times? Anions Cations Percentage abundance of B – 11 = 80.4 %. Question 6. (d) (ii) and (iv). (a) 3 (c) H2SO4 (a) 8 g of CH4 (b) 6.023 Ã 1024 Question 8. Answer: Answer: (a) 1 litre of N2 (a) 0.4 mole 1 mol of alumina (Al2O3) = 102 g = 5 Ã 256 = 1280 g, (iv) 4 moles of phosphorous molecule, P4 = 1.204 Ã 1024 atoms, (b) 1 mole of oxygen = 32 g (d) Correct (He) (b) Deuterium Write the different types of isotopes of oxygen and its percentage abundance. (a) Both (A) and (R) are correct, Question 2. (b) 8 g of O2 molecules Reason (R): The atoms of the same element with the same mass number but different at numbers are called isotopes. (c) 0.24 litre 1.008 amu. (i) 2 g of nitrogen (d) Helium. Ignore if with different plant species / different abiotic variables 1 max 1 2 Total 7 marks One mole of water weighs 18 g. Compounds composed of metals and non-metals contain charged species. In three moles of ethane (C2H6), calculate the following: Question 5. (b) 240 g of calcium and 240 g of magnesium elements have a mole ratio of 3 : 5. An atom is no longer indestructible. Answer: Atomic mass of 1(S) = 1 Ã 32 = 32 Answer: No. An Introduction to Chemistry. Homo. Calcium carbonate is decomposed on heating in the following reaction CaCO3 â CaO + CO2 Isotopes. Answer: Question 6. = $$\frac{6.023Ã10^{23}}{18}$$ Ã 0.18 (a) 1 g of CO2 (a) 22.4 litre at 1 atm and 250Â°C x + y = 1 Question 20. (d) Hydrogen. of moles = $$\frac{8}{2}$$ = 4 moles. Answer: â´ 0.056 g of Al2O3 = $$\frac{1 \times 0.056}{102}$$ mol (iv) 8 g of calcium Number of moles = $$\frac{\text { Mass }}{\text { Atomic mass }}$$ Question 7. Answer: Answer: â´ 0.1 mole of CCl4 = 0.1 Ã 6.022 Ã 1023 molecules of CCl4 Hint: One mole = Molar mass = 2 + 16 = 18 g. Question 50. Which of the following contains the largest number of molecules? (b) Glucose If it conductsm it is salt. Solution: Question 3. Assertion (A): Water, Ammonia (H2O, NH3) are heteroatomic molecules. Solution: One mole of H2O corresponds to _____. (b) 11, Question 52. Answer: (a) 6.023 Ã 1023, Question 5. Hint: (a) Sulphur, Question 20. (b) Gay – Lussacâs law = $$\frac{40}{64}$$ = 0.625 moles (d) 2 dmÂ³ Mass of 2 moles of H2 molecule (a) 64 % 1 mole of steel screws = 6.022 Ã 1023 screws Analyse the table and fill in the blanks. (ii) Atomic mass of 1(N) = 1 Ã 14 = 14 g Given, H = 1, O = 16. Question 11. Answer: Atoms of different elements join together in definite proportions to form molecules of compounds. Find the percentage of nitrogen in ammonia. Answer: (a) Sulphur Solution: â´ 2 g of chlorophyll will contain Mg Give their correct symbols. Others are less. (d) 1 g of Fe (a) Atomic masses of the elements A and B. 1 mol of water contains 2 Ã 6.022 Ã 1023 atoms of hydrogen The percentage composition of elements is useful to determine _____ and _____. (b) (A) is correct but (R)is wrong, Question 9. A negatively charged ion is called an anion and the positively charged ion is called cation. (ii) 1.51 Ã 1023 molecules of NH4Cl = 3.011 Ã 1023 molecules of H2. 4.4 g of CO2 will occupy $$\frac{22.4}{44}$$ Ã 4.4 = $$\frac{22.4}{10}$$ = 2.24 litre. (b) isobars 1 mole of Ca (40 g) and 1 mole of the Oxygen atom (16 g) combine to form 1 mole of CaO (56 g). (a) Glucose The mass of an atoms of an element is known as Atomic mass. The charged species are known as ions. Atomicity = $$\frac{\text { Molecular mass }}{\text { Atomic mass }}$$ (b) 2 litres of H2 Homo atomic molecule. Answer: (a) Incorrect, the correct symbol of cobalt is Co. Which one of the following is a hetero diatomic molecule? Correct statement: Equal volume of all gases under similar conditions of temperature and pressure contain the same number of molecules. Pages (550 words) Approximate price: $22. (a) Both (A) and (R) are correct Mass of sulphur = 32 g Question 24. Answer: = 6.023 Ã 1021 water molecules, Question 2. 1 molecule of methane contains electrons = 6 + 4 = 10 Mass of oxygen = 56 – 40 = 16 g. (ii) $$\frac{\text { No of moles of oxygen atom }}{\text { Mole }=\text { mass/atomic mass }}=\frac{16}{16}=1 \text { mole }$$ It provides results for the number of necessary calories based on a one or two-pound gain or loss per week. One mole of a substance represents one gram formula mass of the substance. Answer: Name two scientists who established the laws of chemical combination? Question 5. (d) 0.1 litre. (a) diatomic (ii) CO2 (c) (A) is correct but (R) is wrong Calculate the mass of 0.5 moles of iron. True. Eg: Isobars 18Ar40, 20Ca40. Answer: Answer: Number of moles = $$\frac{\text { Mass }}{\text { atomic mass }}=\frac{23}{23}$$ = 1 mole of sodium. (ii) Hydrogen peroxide (H2O2) According to Law of multiple proportions Answer: (b) (A) is correct but (R) is wrong Mass number. How many molecules are there in a certain mass of a substance? Find the ratio of mass of the combining elements in the following compounds: Gram molar mass of CO2 = 44 g. (iii) Ca3(PO4)2 (d) 1.5 Ã 1023 = $$\frac { 11.2 }{ 22.4 }$$ GMM = 3(1) + 1(31)+ 4(16) = 98 g False. Since 1 formula unit CaCl2 gives 3 ions, therefore, 1 mole of CaCl2 will give 3 moles of ions. (i) 52 moles of He â´ 6.022 Ã 1023 atoms of oxygen = 1 mol The difference in the mass of 100 moles each of sodium atoms and sodium ions is 5.48002 g. Compute the mass of an electron. (c) relative molecular mass Correct statement: H2O, NH3, CH4 are examples of heteroatomic molecules. Mass = 0.1 Ã 64 Solution: 22.4 litre of NH3 = 1 mole = 100 g. (iii) How many moles of CO2 are there in this equation? 1 gm atom of nitrogen represents: (b) Hydrogen chloride, Question 19. (b) 4 moles 4C3H5((NO3))3 (l) â 12CO2 (g) + 10H2O (l) + 6N2 (g) + O2 (g) Answer: Number of moles = $$\frac{\text { Number of atoms of iron }}{\text { Avogadro’s number }}$$ Thus, let the number of molecules in one volume = n, then. (d) Atomicity. (c) isotopes, Question 13. Atomicity of chlorine = $$\frac{48}{16}$$ = 3. Ammonia gas is formed by the following reaction Mass of silver = m g. Question 14. True. = 2 Ã 2 = 4 g, (ii) 3 moles of chlorine molecule, Cl2 (a) Both (A) and (R) are correct Solution: IV. Daltonâs atomic theory states that atoms of different elements combine together in simple whole number ratio. Answer: = 120 + (94 Ã 2) Calculate the number of electrons present in 15.4 g of carbon tetrachloride (CCl4). (a) 0.4 mole Question 1. 1 mole of calcium chloride = 111 g = 3.6132 Ã 1024 ions. Answer: (a) Atomic mass of A = $$\frac{70}{1.25}$$ = 56 (b) 18 g of O2 Atomic mass of 1(O) = 1 Ã 16 = 16 6.022 Ã 1022Â molecules of oxygen = 1 mol 2013-2014 Visiting Lecturer, University of Oregon. Answer: (i) Tri-atomic molecules are CaCl2, H2O. Give the salient features of âModern atomic theoryâ. of molecules = $$\frac{1}{44}$$ Ã 6.023 Ã 1023 False. Answer: Gram atomic mass of Ca = 40 g Answer: Question 7. Question 2. Mass of glucose = $$\frac{\text { Molecular mass } \times \text { number of particles }}{\text { Avogadro’s number }}$$ Gram molar mass of glucose (C6H12O6) = (6 Ã 12) + (12 Ã 1) + (6 Ã 16) One mole of any gas occupies _____ ml at S.T.P. (a) 44 g A mole is the amount of a substance which contains the same number of chemical units (atoms, molecules or ions) as there are atoms in exactly 12 g of carbon-12. (c) 11.2 L of N2 at STP, Question 18. Question 2. Answer: Atoms of the same element with same atomic number but having different mass number are called _____. Which of the following has the smallest mass? Calculate the number of molecules in 360 g of glucose. (d) Dalton’s law. (Given Atomic masses: Ag = 108 u, S = 32 u, N = 14 u, Ca = 40 u) Volume occupied by N2 at S.T.P = No. Question 6. Ratio is 6 : 10 (b) 18 g. Question 10. Give an example. (At. Solution: Answer: (b) Cl– Na+ Answer: The average atomic mass of carbon is _____. For example, water, ammonia, carbon dioxide. Question 9. Hint: Molar mass = 12 + (16 Ã 2) = 44 g. Question 30. No. Answer: Solution: Calculate the volume occupied by: Question 54. Atomicity = $$\frac{\text { Molecular mass }}{\text { Atomic mass }}$$ [NCERT Exemplar] (b) Hydrogen chloride 1 molecule of ozone (O3) = 3 atoms of oxygen = 2 + 12 + 48 Answer: (d) both (a) and (b), Question 3. Number of moles = $$\frac{\text { Mass }}{\text { atomic mass }}=\frac{32}{32}$$ = 1 mole of sulphur. Answer: (d) Hydrogen (d) C2H5OH Hint. The mass of one steel screw is 4.1 lg. If the molecule is made of similar kind of atoms, then it is called homoatomic molecule. of moles of Sodium = $$\frac { 4.6 }{ 23 }$$ = 0.2 moles of sodium, No. }}{2 \times \text { Mass of } 1 \text { atom of hydrogen }}\) Calculate the mass percentage of oxygen present in the following compounds and state the law of chemical combination associated. Which one of the following is a hetero triatomic molecule? Solution: One mole. The stable isotope of _____ is used as the standard for measuring the relative atomic mass of an element. Molar mass of H2SO4 = (1 Ã 2) + (32 Ã 1) + (16 Ã 4) One mole of gold contains NA atoms = 6.022 Ã 1023 = 0.0016 g, Question 13. % relative abundance of B – 11 = ? Answer: Answer: Question 2. (iv) What mass of calcium will be obtained from 1000 g of calcium oxide? Question 25. Answer: Atoms of different elements having ______ mass number, but ______ atomic numbers are called isobars. The gram atomic mass of an element has no unit? (d) 28 g of nitrogen Answer: of moles = $$\frac{\text { Mass }}{\text { Atomic mass }}$$ Answer: of molecules }}{\text { Avogadro number }}} \\ {=\frac{24.092 \times 10^{22}}{6.023 \times 10^{23}}}\end{array}\) (i) 392 g of sulphuric acid (c) 320 g of Sulphur Number of molecules in a certain mass (a) 18 g of H2O 1 mol of CaC03 = 100 g, Question 4. Formula = No. Formula mass of sodium carbonate Hint: Gram molar mass of Ca3(PO4)2 = 308 g. You can Download Samacheer KalviÂ 10th Science Guide PdfÂ Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations. (b) MgCl2 (ii) What is the mass of sodium bicarbonate used in this equation? = 26.9984 g mol-1 Carbon dioxide produced by action of dilute hydrochloric acid on potassium hydrogen carbonate is moist whereas that produced by heating potassium hydrogen carbonate is dry. For example, sodium chloride, calcium oxide. Correct statement: The number of atoms present in the molecule is called its Atomicity. Calculation based on number of moles from mass and volume: Question 1. Solution: (k) 1 (Noble gases do not combine and exist as monoatomic gases) (c) (A) is correct but (R) is wrong Answer: (b) (A) is correct but (R) is wrong (c) Incorrect, the correct symbol of aluminium is Al. Solution: Atoms which have the same number of protons but different number of neutrons are called _____. (i) 392 g of sulphuric acid Answer: The Relative molecular mass of a molecule is the ratio between the mass of one molecule of the substance to 1 / 12th mass of an atom of Carbon – 12 isotope. Give examples. (e) CO (a) F2 The solubility generally, increases with increase in temperature. = 46 + 12 + 48 + 180 = 286 u, Question 6. Answer: Vapour Density (V.D.) Answer: 44 g of CO2 occupied 22.4 litre of volume. The molecule that consists of atoms of different elements is called a heteroatomic molecule. Give two examples. â´ The mass of 1 atom of gold = $$\frac{197}{6.023Ã10^{23}}$$ Ã 1 How many (a) molecules (b) hydrogen atoms (c) oxygen atoms are there in 0.5 mol of water? (a) 1 litre of N2, Question 28. How many grams are there in Question 21. Flask Q has a greater number of oxygen atoms as compared to the flask P. Question 3. x = % abundance of B – 10 = 0.196 Ã 100 = 19.6 % (a) (i) only of moles of atoms Define Relative atomic mass. (b) V â n (d) Helium He (a) Berzilliu’s hypothesis Number of molecules = 0.2678 Ã 6.023 Ã 1023 = 1.6129 Ã 1023 molecules. The atomic number of three elements A, B and C are 9, 10 and 13 respectively. Atomic mass of 2(O) = 2 Ã 16 = 32 Isotopes of oxygen: 2.24 litre of SO2 gas at S.T.P? (iv) Chemical equation of the reaction (a) isotopes, Question 43. 1 atom of oxygen = $$\frac{1}{6.022 \times 10^{23}}$$ mol e.g.. (c) HI, Question 16. (a) H2O, Question 17. Mass of lithium = 1.4 g (b) 2 Give any two applications of Avogadro’s law. of molecules = $$\frac{1}{28}$$ Ã 6.023 Ã 1023 Atomicity of an element is equal to _____. (b) 1 g of H2 Answer: Give one word for the following: (b) 3 (iv) 1.2044 Ã 1025 molecules of water Answer: (d) Heavy hydrogen $$_{1} \mathrm{D}^{2}$$. Analysis _____ is one-twelfth of the mass of C – 12 atom, an isotope of carbon which contains _____ protons and ____ neutrons. (iv) Atoms of one element can be transmuted into atoms of other elements. Answer: The gram molecular mass of oxygen molecule is: So the answer (b) is correct. Relative molecular mass (hydrogen scale) \(=\frac{\text { Mass of } 1 \text { molecule of a gas or vapour at STP. Gram molecular mass of CaO = 40 + 16 = 56 g Question 23. The value of gram molar mass of CO2 is _____. In the formula of C12H22O11 the carbon, hydrogen and oxygen combine in whole number ratio but the ratio is not simple. 2 Ã Vapour density is equal to _____. The weight % of Mg as 2.68 You can not provide us with more time, a 100 % refund is guaranteed definition 1 mole atoms the... + 2 ( 16 Ã 2.5 = 40 u, Avogadro No with five volumes of has. Ã 64 mass of 0.5 moles of electrons are to be lg cm-3 terms! Study guides, lab experiments, and that of oxygen atoms ) atomicity amu! I, e – iv oxygen, Question 12 _____ and the _____ of gases who established the of. 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