Author: Anonymous

6. If water has a heat of vaporization of 40.7 kJ/mol, how much energy is needed to vaporize 2.00 mol?

61. What is the half-life of a substance if its rate constant k = 0.693 hr⁻¹?

7. How many joules are required to melt 10.0 g of ice at 0 °C? (ΔHfus = 6.01 kJ/mol)

72. What is the entropy change ΔS when 10.0 g of ice melts at 0 °C? (ΔHfus = 6.0 kJ/mol, molar mass H₂O = 18 g/mol, T = 273 K)

10. What is the geometry of PCl₅?

75. A buffer solution is made by mixing 0.10 mol acetic acid and 0.10 mol sodium acetate in 1.0 L solution. If Ka = 1.8×10⁻5, what is the pH of the buffer?

9. A 5.0 g sample of liquid requires 150 J to increase temperature by 10 °C. What is its specific heat capacity?

65. If a galvanic cell produces a current of 2.0 A for 1.0 hour, how many moles of electrons are transferred? (Faraday’s constant = 96,500 C/mol e⁻)

55. How many grams of KCl (molar mass = 74.5 g/mol) are needed to prepare 250 mL of a 2.0 M solution?

30. When 4.0 grams of hydrogen gas react completely with oxygen gas, how many grams of water are produced? (Reaction: 2H₂ + O₂ → 2H₂O)