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Quantitative Chemistry

Quantitative Chemistry. Click to start. A. 0.1. B. 1 x 10 -22. C. 3.6 x 10 25. 60. D. Question 1. What is the mass in grams of one molecule of ethanoic acid CH 3 COOH?. Wrong Answer!. Molar mass of CH 3 COOH is 24 + 4 + 32 = 60. Try Again.

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Quantitative Chemistry

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  1. Quantitative Chemistry Click to start

  2. A 0.1 B 1 x 10-22 C 3.6 x 1025 60 D Question 1 What is the mass in grams of one molecule of ethanoic acid CH3COOH?

  3. Wrong Answer! Molar mass of CH3COOH is 24 + 4 + 32 = 60 Try Again

  4. One mole of methane contains four moles of hydrogen atoms. A B One mole of 12C has a mass of 12.00g. One mole of methane contains 75% of carbon by mass. One mole of hydrogen gas contains 6.02 x 1023 atoms of hydrogen. C D Question 2 Which is not a true statement?

  5. Wrong Answer! 1 mole of hydrogen gas contain 6 x 1023 molecules of hydrogen gas. Since 1 mole of hydrogen is made up of 2 H atoms, 1 mole of hydrogen gas contains 2 x 6 x 1023 atoms. Try Again

  6. A 1.0 mol N2H4 B 2.0 mol N2 C 3.0 mol NH3 25.0 mol H2 D Question 3 Which sample has the greatest mass?

  7. Wrong Answer! A: 1 x (28+4) = 32g B: 2 x 28 = 56g C: 3 x (14+3) = 51g D: 25 x 2 = 50g Try Again

  8. A Both I and II B Neither I nor II C I only II only D Question 4 Which one of the following statements about SO2 is/are correct? • One mole of SO2 contains 1.8 x 1024 atoms • One mole of SO2 has a mass of 64g

  9. Wrong Answer! SO2 is made up of 3 atoms, hence 1 mole of SO2 contains 3 x 6 x 1023 atoms. Molar mass of SO2 = 32 + 32 = 64. Try Again

  10. A B two chlorine atoms two chlorine molecules C two chloride ions four free chlorine atoms D Question 5 2Cl2 represents:

  11. Wrong Answer! 2Cl2 represents two chlorine molecules : Cl-Cl and Cl-Cl Try Again

  12. A B Mg(s)+ H2O(l) Mg(OH)2(aq)+H2(g) Ca(s)+2H+(aq) Ca 2+(aq)+H2(g) C Fe 2+(aq)+Ag+(aq) Fe3+(aq)+ 2Cl-(aq) Fe 2+(aq)+ Cl2(g)  Fe3+(aq)+ 2Cl-(aq) D Question 6 Which one of the following equations is not correctly balanced?

  13. Wrong Answer! The charge is not balanced. Try Again

  14. A 6.25 cm3 B 50 cm3 C 12.5 cm3 25.0 cm3 D Question 7 Sulfuric acid and sodium hydroxide react together according to the equation? H2SO4(aq) + 2NaOH(aq)  Na2SO4(aq) + 2H2O(l) What volume of 0.250 moldm-3 NaOH is required to neutralise exactly 25.0 cm3 of 0.125 moldm-3 H2SO4?

  15. Wrong Answer! Conc x Vol of NaOH = 2 x Conc x Vol of H2SO4 0.25 x Vol of NaOH = 2 x 0.125 x 25 Vol of NaOH = 25 cm3 Try Again

  16. A B C D Question 8 Which expression represents the density of a gas sample of relative molar mass, Mr, at temperature T, and pressure, P?

  17. Wrong Answer! Try Again

  18. A They have the same volume. B There are equal numbers of moles in the two samples. C They have the same relative molecular mass. They condense at the same temperature. D Question 9 Separate samples of two gases, each containing a pure substance, are found to have the same density under the same conditions of temperature and pressure. Which statement about these two samples must be correct?

  19. Wrong Answer! Under the same pressure and temperature where R is a constant, they should have the same relative molecular mass. Try Again

  20. A B C D Question 10 A 250 cm3 sample of an unknown gas has a mass of 1.42g at 350C and 0.85 atmospheres. Which expression gives its molar mass, Mr? (R = 82.05 cm3 atm K-1 mol-1)

  21. Wrong Answer! Try Again

  22. A 0.60 moldm-3 B 0.90 moldm-3 C 1.20 moldm-3 1.80 moldm-3 D Question 11 What is the concentration of nitrate ions in 0.500cm3 of 0.60moldm-3 Fe(NO3)3 solution?

  23. Wrong Answer! Fe(NO3)3 Fe3+(aq) + 3NO3-(aq) Nitrate ions concentration = (0.6 x 3) = 1.80 moldm-3 Try Again

  24. A MS B MS2 C M2S M2S5 D Question 12 32.0 grams of sulfur (atomic mass of 32.0) combine with a metal, M (atomic mass of 40.0) to give a product which weighs 52.0g. What is the empirical formula of the sulfide formed?

  25. Wrong Answer! Amount of M atoms = (52-32)/40 = 0.50 mol Amount of S atoms = 32/32 = 1.0 mol Multiplying through by 2 gives MS2 Try Again

  26. A Low Low B Low High C High High High Low D Question 13 Under what conditions of temperature and pressure will a real gas behave most like an ideal gas? Temperature Pressure

  27. Wrong Answer! High pressure will bring the gas molecules very close together. This causes more collisions and also allows the weaker attractive forces to operate. With low temperatures, the gas molecules do not have enough kinetic energy to continue on their path to avoid the attraction. Try Again

  28. A 77 gmol-1 B 47 gmol-1 C 39 gmol-1 4 gmol-1 D Question 14 At stp (i.e. 00C and 1 atm pressure (101 kPa)), it was found that 1.15 dm3 of a gas weighed 3.96g. What is its molar mass?

  29. Wrong Answer! Try Again

  30. A Average speed of the atoms B Pressure of the gas C Average kinetic energy of the atoms Density of the argon D Question 15 A sample of argon gas in a sealed container of fixed value is heated from 50 to 2500C. Which quantity will remain constant?

  31. Wrong Answer! All properties will increase in value except density which remain constant since the mass and volume of gas remain constant. Try Again

  32. A 40% B 60% C 80% 100% D Question 16 Nitrogen(II) oxide,NO, is made from the oxidation of NH3: 4NH3 + 5O2 4NO + 6H2O An 8.5g sample of NH3 gives 15.0g of NO. What is the percentage yield of NO?

  33. Wrong Answer! Amount of NH3 = 8.5/17 = 0.5 mol Amount of NO = 15/30 = 0.5 mol Percentage yield = 0.5/0.5 x 100% = 100% Try Again

  34. A C2H4O2 B CH2O C CH4O CHO D Question 17 A pure compound contains 24g of carbon, 4g of hydrogen and 32g of oxygen. No other elements are present. What is the empirical formula of the compound?

  35. Wrong Answer! No. of moles of C = 24/12 = 2 No. of moles of H = 4/1 = 4 No. of moles of O = 32/16 = 2 Dividing all by 2 gives a ratio of C:H:O = 1:2:1 The empircal formula is CH2O Try Again

  36. A 4NH3 + 7O2 4NO2 + 6H2O B 4NH3 + 5O2 4NO + 6H2O C 4NH3 + 5O2 4N2O2 + 6H2O 4NH3 + 3O2 2N2+ 6H2O D Question 18 1000cm3 of ammonia gas combines with 1250cm3 of oxygen to produce two gaseous compounds with a combined volume of 2500cm3, all volumes being measured at 2000C and 0.500 atm pressure. Which of the following equations fits the facts?

  37. Wrong Answer! 4 vol + 5 vol  10 vol Experimental data 1 vol + 1.25 vol  2.5 mol Multiplying throughout by 4 gives 4 vol + 5 vol  10 vol Try Again

  38. A Neither B Butane C Oxygen Oxygen and butane D Question 19 Butane burns in oxygen according to the equation 2C4H10(g) + 13O2(g)  8CO2(g) + 10H2O(g) If 11.6g of butane is burned in 11.6g of oxygen which is the limiting reagent?

  39. Wrong Answer! No. of moles of butane = 11.6/58 = 0.2 No. of moles of oxygen = 11.6/32 = 0.3625 2 mols of butane react with 13 mols of oxygen 0.2 mols of butane will react with 1.3 mols of oxygen. 0.3625 mols of oxygen will react with 0.05577 mols butane. The limiting reagent is oxygen since the no. of mols of butane produced by 0.3625 mols is smaller. Try Again

  40. A 318cm3 B 450cm3 C 477cm3 220cm3 D Question 20 A 350cm3 sample of helium gas is collected at 22.00C and 99.3kPa. What volume would this gas occupy?

  41. Wrong Answer! Try Again

  42. A 1.45 B 2.90 C 2.50 2.42 D Question 21 When 250 cm3 of 3.00 moldm-3 HCl(aq) is added to 350 cm3 of 2.00 moldm-3 HCl(aq) the concentration of the solution of hydrochloric acid obtained in moldm-3 is:

  43. Wrong Answer! (250+350)/1000 x Conc of HCl = 250/1000 x 3 + 350/1000 x 2 Conc of HCl = (0.25 x 3 + 0.35 x 2)/0.6 = 2.416moldm-3 Try Again

  44. A 2.0g B 0.8g C 0.4g 0.2g D Question 22 Magnesium reacts with hydrochloric acid according to the following equation: Mg(s) + 2HCl(aq)  MgCl2(aq) + H2(g) What mass of hydrogen will be obtained if 100 cm3 of 2.00 moldm-3 HCl are added to 4.86g of magnesium?

  45. Wrong Answer! No. of moles of HCl = 100/1000 x 2 = 0.2 No. of moles of Mg = 4.86/24 = 0.2025 The limiting reagent is HCl Since 2 mols of HCl produces 1 mol H2, 0.2 mols of HCl produces 0.1 mol H2. Hence, 0.1 x 2g = 0.2g of H2 Try Again

  46. A MgSO4.9H2O B MgSO4.7H2O C MgSO4.5H2O MgSO4.3H2O D Question 23 12g of anhydrous magnesium sulfate combines with 12.6g of water to form hydrated manesium sulfate. What is the formula of the hydrated magnesium sulfate?

  47. Wrong Answer! No. of moles of MgSO4 = 12/122 = 0.09836 No. of moles of H2O = 12.6/18 = 0.7 Multiplying by 10 to both gives approximately 1 mole MgSO4 and 7 moles H2O Try Again

  48. A 60 cm3 B 160 cm3 C 200 cm3 240 cm3 D Question 24 In order to dilute 40.0 cm3 of 0.600 moldm-3 HCl(aq) to 0.100 moldm-3, what volume of water must be added?

  49. Wrong Answer! M1V1= M2V2 0.600moldm-3 x 40.0cm3 = 0.600moldm-3 x V2 V2 = 240cm3 V2 – V1 = 240 – 40 = 200cm3 Try Again

  50. Congratulations!

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