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Page 1 1. (c) According to law of conservation of mass "mass is neither created nor destroyed during a chemical change" ? Mass of the reactants = Mass of products x + 4.9 = 6 + 1.825 or x = 2.925 g 2. (b) Moles of urea present in 100 ml of sol.= ? [ M = Moles of solute present in 1L of solution] 3. (d) Relative atomic mass = or Now if we use 1 / 6 in place of 1 / 12 the formula becomes ? . 4. (d) 1 Mole of Mg 3 (PO 4 ) 2 contains 8 mole of oxygen atoms ? 8 mole of oxygen atoms = 1 mole of Mg 3 (PO 4 ) 2 ? mole of Mg 3 (PO 4 ) 2 0.25 mole of oxygen atom mole of Mg 3 (PO 4 ) 2 mole of Mg 3 (PO 4 ) 2 5. (b) From Page 2 1. (c) According to law of conservation of mass "mass is neither created nor destroyed during a chemical change" ? Mass of the reactants = Mass of products x + 4.9 = 6 + 1.825 or x = 2.925 g 2. (b) Moles of urea present in 100 ml of sol.= ? [ M = Moles of solute present in 1L of solution] 3. (d) Relative atomic mass = or Now if we use 1 / 6 in place of 1 / 12 the formula becomes ? . 4. (d) 1 Mole of Mg 3 (PO 4 ) 2 contains 8 mole of oxygen atoms ? 8 mole of oxygen atoms = 1 mole of Mg 3 (PO 4 ) 2 ? mole of Mg 3 (PO 4 ) 2 0.25 mole of oxygen atom mole of Mg 3 (PO 4 ) 2 mole of Mg 3 (PO 4 ) 2 5. (b) From V 1 = 6. (d) Weight of Iron in 67200 = Number of atoms of Iron = 7. (a) 2Al(s) + 6HCl(aq) 2Al 3+ (aq) + 6Cl – (aq) + 3H 2 (g) 6 moles of HCl produces = 3 moles of H 2 = 3 × 22.4 L of H 2 at S.T.P 1 mole of HCl produces = L of H 2 at S.T.P = 11.2 L of H 2 at STP 8. (a) 95% H 2 SO 4 by weight means 100g H 2 SO 4 solution contains 95g H 2 SO 4 by mass. Molar mass of H 2 SO 4 = 98g mol –1 Moles in 95g = = 0.969 mole Volume of 100g = 54.52 cm 3 = 54.52 × 10 –3 L 9. (c) 50 mL of 16.9% solution of AgNO 3 = 8.45 g of Ag NO 3 n mole = = 0.0497 moles 50 ml of 5.8% solution of NaCl contain Page 3 1. (c) According to law of conservation of mass "mass is neither created nor destroyed during a chemical change" ? Mass of the reactants = Mass of products x + 4.9 = 6 + 1.825 or x = 2.925 g 2. (b) Moles of urea present in 100 ml of sol.= ? [ M = Moles of solute present in 1L of solution] 3. (d) Relative atomic mass = or Now if we use 1 / 6 in place of 1 / 12 the formula becomes ? . 4. (d) 1 Mole of Mg 3 (PO 4 ) 2 contains 8 mole of oxygen atoms ? 8 mole of oxygen atoms = 1 mole of Mg 3 (PO 4 ) 2 ? mole of Mg 3 (PO 4 ) 2 0.25 mole of oxygen atom mole of Mg 3 (PO 4 ) 2 mole of Mg 3 (PO 4 ) 2 5. (b) From V 1 = 6. (d) Weight of Iron in 67200 = Number of atoms of Iron = 7. (a) 2Al(s) + 6HCl(aq) 2Al 3+ (aq) + 6Cl – (aq) + 3H 2 (g) 6 moles of HCl produces = 3 moles of H 2 = 3 × 22.4 L of H 2 at S.T.P 1 mole of HCl produces = L of H 2 at S.T.P = 11.2 L of H 2 at STP 8. (a) 95% H 2 SO 4 by weight means 100g H 2 SO 4 solution contains 95g H 2 SO 4 by mass. Molar mass of H 2 SO 4 = 98g mol –1 Moles in 95g = = 0.969 mole Volume of 100g = 54.52 cm 3 = 54.52 × 10 –3 L 9. (c) 50 mL of 16.9% solution of AgNO 3 = 8.45 g of Ag NO 3 n mole = = 0.0497 moles 50 ml of 5.8% solution of NaCl contain NaCl = n NaCl = = 0.0495 moles AgNO 3 + NaCl ? AgCl? + Na + Cl 1 mole 1 mole 1 mole ? 0.049 mole 0.049 mole 0.049 mole of AgCl n = w = (n AgCl ) × Molecular Mass = (0.049) × (107.8 + 35.5) = 7.02 g 10. (b) Number of valence electrons in a ion = 1 Now, 1 mol or 42 g of has = 6.023 × 10 23 ions So, 42 g of has 6.023 × 4 × 10 23 valence e – 1 g of has valence e – 4.2 g of has valence e – i.e., 0.1 N A valence e – . 11. (c) 74.75% of chlorine means 74.75g chlorine is present in 100g of metal chloride. Weight of metal = 100g – 74.75g = 25.25g Equivalent weight = 12 Valency of metal ? Formula of compound = MCl 4 12. (d) Q 18 gm, H 2 O contains = 2 gm H Page 4 1. (c) According to law of conservation of mass "mass is neither created nor destroyed during a chemical change" ? Mass of the reactants = Mass of products x + 4.9 = 6 + 1.825 or x = 2.925 g 2. (b) Moles of urea present in 100 ml of sol.= ? [ M = Moles of solute present in 1L of solution] 3. (d) Relative atomic mass = or Now if we use 1 / 6 in place of 1 / 12 the formula becomes ? . 4. (d) 1 Mole of Mg 3 (PO 4 ) 2 contains 8 mole of oxygen atoms ? 8 mole of oxygen atoms = 1 mole of Mg 3 (PO 4 ) 2 ? mole of Mg 3 (PO 4 ) 2 0.25 mole of oxygen atom mole of Mg 3 (PO 4 ) 2 mole of Mg 3 (PO 4 ) 2 5. (b) From V 1 = 6. (d) Weight of Iron in 67200 = Number of atoms of Iron = 7. (a) 2Al(s) + 6HCl(aq) 2Al 3+ (aq) + 6Cl – (aq) + 3H 2 (g) 6 moles of HCl produces = 3 moles of H 2 = 3 × 22.4 L of H 2 at S.T.P 1 mole of HCl produces = L of H 2 at S.T.P = 11.2 L of H 2 at STP 8. (a) 95% H 2 SO 4 by weight means 100g H 2 SO 4 solution contains 95g H 2 SO 4 by mass. Molar mass of H 2 SO 4 = 98g mol –1 Moles in 95g = = 0.969 mole Volume of 100g = 54.52 cm 3 = 54.52 × 10 –3 L 9. (c) 50 mL of 16.9% solution of AgNO 3 = 8.45 g of Ag NO 3 n mole = = 0.0497 moles 50 ml of 5.8% solution of NaCl contain NaCl = n NaCl = = 0.0495 moles AgNO 3 + NaCl ? AgCl? + Na + Cl 1 mole 1 mole 1 mole ? 0.049 mole 0.049 mole 0.049 mole of AgCl n = w = (n AgCl ) × Molecular Mass = (0.049) × (107.8 + 35.5) = 7.02 g 10. (b) Number of valence electrons in a ion = 1 Now, 1 mol or 42 g of has = 6.023 × 10 23 ions So, 42 g of has 6.023 × 4 × 10 23 valence e – 1 g of has valence e – 4.2 g of has valence e – i.e., 0.1 N A valence e – . 11. (c) 74.75% of chlorine means 74.75g chlorine is present in 100g of metal chloride. Weight of metal = 100g – 74.75g = 25.25g Equivalent weight = 12 Valency of metal ? Formula of compound = MCl 4 12. (d) Q 18 gm, H 2 O contains = 2 gm H ? 0.72 gm H 2 O contains = Q 44 gm CO 2 contains = 12 gm C ? 3.08 gm CO 2 contains = ? C : H = = 0.07 : 0.08 = 7 : 8 ? Empirical formula = C 7 H 8 13. (a) Na 2 CO 3 + NaHCO 3 + NaCl + HCl (excess) Thus, on complete reaction with HCl, 1kg of washing soda will evolve 9 mol of CO 2 . 14. (a) 2.6 has two significant figures. 0.260 has three significant figures. 0.002600 has four significant figures. 2.6000 has five significant figures. 15. (b) Given mass of solute (w) = 120 g mass of solvent (w) = 1000 g Mol. mass of solute = 60 g density of solution = 1.12 g/ ml From the given data, Page 5 1. (c) According to law of conservation of mass "mass is neither created nor destroyed during a chemical change" ? Mass of the reactants = Mass of products x + 4.9 = 6 + 1.825 or x = 2.925 g 2. (b) Moles of urea present in 100 ml of sol.= ? [ M = Moles of solute present in 1L of solution] 3. (d) Relative atomic mass = or Now if we use 1 / 6 in place of 1 / 12 the formula becomes ? . 4. (d) 1 Mole of Mg 3 (PO 4 ) 2 contains 8 mole of oxygen atoms ? 8 mole of oxygen atoms = 1 mole of Mg 3 (PO 4 ) 2 ? mole of Mg 3 (PO 4 ) 2 0.25 mole of oxygen atom mole of Mg 3 (PO 4 ) 2 mole of Mg 3 (PO 4 ) 2 5. (b) From V 1 = 6. (d) Weight of Iron in 67200 = Number of atoms of Iron = 7. (a) 2Al(s) + 6HCl(aq) 2Al 3+ (aq) + 6Cl – (aq) + 3H 2 (g) 6 moles of HCl produces = 3 moles of H 2 = 3 × 22.4 L of H 2 at S.T.P 1 mole of HCl produces = L of H 2 at S.T.P = 11.2 L of H 2 at STP 8. (a) 95% H 2 SO 4 by weight means 100g H 2 SO 4 solution contains 95g H 2 SO 4 by mass. Molar mass of H 2 SO 4 = 98g mol –1 Moles in 95g = = 0.969 mole Volume of 100g = 54.52 cm 3 = 54.52 × 10 –3 L 9. (c) 50 mL of 16.9% solution of AgNO 3 = 8.45 g of Ag NO 3 n mole = = 0.0497 moles 50 ml of 5.8% solution of NaCl contain NaCl = n NaCl = = 0.0495 moles AgNO 3 + NaCl ? AgCl? + Na + Cl 1 mole 1 mole 1 mole ? 0.049 mole 0.049 mole 0.049 mole of AgCl n = w = (n AgCl ) × Molecular Mass = (0.049) × (107.8 + 35.5) = 7.02 g 10. (b) Number of valence electrons in a ion = 1 Now, 1 mol or 42 g of has = 6.023 × 10 23 ions So, 42 g of has 6.023 × 4 × 10 23 valence e – 1 g of has valence e – 4.2 g of has valence e – i.e., 0.1 N A valence e – . 11. (c) 74.75% of chlorine means 74.75g chlorine is present in 100g of metal chloride. Weight of metal = 100g – 74.75g = 25.25g Equivalent weight = 12 Valency of metal ? Formula of compound = MCl 4 12. (d) Q 18 gm, H 2 O contains = 2 gm H ? 0.72 gm H 2 O contains = Q 44 gm CO 2 contains = 12 gm C ? 3.08 gm CO 2 contains = ? C : H = = 0.07 : 0.08 = 7 : 8 ? Empirical formula = C 7 H 8 13. (a) Na 2 CO 3 + NaHCO 3 + NaCl + HCl (excess) Thus, on complete reaction with HCl, 1kg of washing soda will evolve 9 mol of CO 2 . 14. (a) 2.6 has two significant figures. 0.260 has three significant figures. 0.002600 has four significant figures. 2.6000 has five significant figures. 15. (b) Given mass of solute (w) = 120 g mass of solvent (w) = 1000 g Mol. mass of solute = 60 g density of solution = 1.12 g/ ml From the given data, Mass of solution = 1000 + 120 = 1120 g or Volume of solution or = 1 litre Now molarity (M) = = 16. (d) In an unknown compounds containing N and H given % of H = 12.5% ? % of N = 100 – 12.5 = 87.5% 2 × vapour density = Mol. wt = mol wt. = 16 × 2 = 32. Molecular formula = n × empirical formula mass = 2 ? Molecular formula of the compound will be = (NH 2 ) 2 = N 2 H 4 17. (a) 18. (b) The required equation is nascent oxygen [O] required for 1 mol. of Fe(C 2 O 4 ) is 1.5, 5 [O] are obtained from 2Read More
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