exam 3

Electronegativity Values

  • C: 2.5
  • H: 2.1
  • N: 3.0
  • O: 3.5
  • F: 4.0
  • S: 2.5
  • P: 2.1
  • B: 2.0
  • Si: 1.9
  • As: 2.1
  • Sb: 2.0
  • Bi: 2.0

Questions and Answers

Identify Element with Lowest Electronegativity
  1. Which of the following elements has the lowest electronegativity?
    • A) C
    • B) N
    • C) F
    • Correct Answer: A) C
Identify Polar Covalent Bonds
  1. Identify the polar covalent among the following:
    • A) C-H
    • B) C-C
    • C) C-S
    • D) O-H
    • E) F-H
    • Correct Answer: D) O-H
Identify Least Polar Covalent Bond
  1. Identify the least polar covalent in the following:
    • A) C-H
    • B) N-H
    • C) O-H
    • Correct Answer: A) C-H
Molecular Geometry of Compounds

  1. What is the molecular shape of Carbon tetrachloride (CCl4)?

    • A) Trigonal pyramidal
    • B) Linear
    • C) Trigonal planar
    • D) Tetrahedral
    • Correct Answer: D) Tetrahedral

  2. What is the molecular shape of Carbon disulfide (CS2)?

    • A) Trigonal pyramidal
    • B) Linear
    • Correct Answer: B) Linear

  3. What is molecular geometry of AlCl3?

    • A) Trigonal pyramidal
    • B) Linear
    • C) Trigonal planar
    • D) Tetrahedral
    • Correct Answer: C) Trigonal planar

  4. The molecular geometry (shape) of Ammonia (NH3) is?

    • A) Trigonal pyramidal
    • B) Bent
    • Correct Answer: A) Trigonal pyramidal
Identifying Polar and Non-Polar Molecules

  1. Identify the polar molecules among the following:

    • A) CH4
    • B) H2O
    • C) N2
    • D) NH3
    • E) H-F
    • Correct Answer: B) H2O

  2. Identify the non-polar molecules among the following:

    • A) CO2
    • B) NH3
    • C) CH3OH
    • D) F2
    • Correct Answer: A) CO2
Molecular Quantity Calculations

  1. How many molecules will be in 1.5 mol of water?

    • A) 6.022 x 10²³
    • B) 6.022 x 10²²
    • C) 9.033 x 10²³
    • D) 9.033 x 10²⁴
    • Correct Answer: C) 9.033 x 10²³

  2. How many moles of gold in a sample containing 3.011 x 10²³ gold atoms?

    • A) 1 mol
    • B) 2 mol
    • C) 1.5 mol
    • D) 0.5 mol
    • Correct Answer: A) 1 mol

  3. If a sample of silver contains 2.4088 x 10²⁴ silver atoms, how many moles of silver in the sample?

    • A) 1 mol
    • B) 2 mol
    • C) 0.5 mol
    • D) 4 mol
    • Correct Answer: B) 2 mol

  4. What is the molar mass of Acetic acid (CH3COOH)?

    • A) 18 g/mol
    • B) 62 g/mol
    • C) 98 g/mol
    • D) 60 g/mol
    • Correct Answer: B) 62 g/mol

  5. What is the mass of 2.5 moles of glucose? Molar mass of glucose: 180 g/mol

    • A) 270 g
    • B) 98 g
    • C) 180 g
    • Correct Answer: A) 450 g

  6. What is the mass of 5 moles of water (H2O)?

    • Calculation:
      • Molar mass of H2O = 18 g/mol
      • Mass = 5 moles × 18 g/mol = 9090 g
Balancing Chemical Equations
  1. If you were balancing the following chemical equation, what are the correct coefficients of reactants and products?
    • C3H8(g) + 5O2 (g) → 3CO2(g) + 4H2O(g)
    • A) 3, 5, 4, 2
    • B) 1, 5, 3, 3
    • C) 1, 3, 3, 4
    • D) 1, 5, 3, 4
    • Correct Answer: D) 1, 5, 3, 4
Classifying Reactions

  1. Identify the following reaction as combination, decomposition, single displacement, double displacement or combustion reaction?

    • Reaction: 2H2(g) + O2(g) → 2H2O(l)
    • Type: A) Combination

  2. Classify the following reaction:

    • 2C2H6(g) + 7 O2(g) → 4CO2(g) + 6H2O(g)
    • Type: B) Combustion

  3. Classify the following reaction:

    • Zn + 2HCl → ZnCl2 + H2
    • Type: C) Single displacement
Oxidation and Reduction

  1. In the following reaction, which reactant is reduced?

    • O2 (g) + Fe (s) → Fe2O3(s)
    • A) O2
    • B) Fe
    • C) Fe2O3
    • D) none of them are correct
    • Correct Answer: A) O2

  2. Which one is getting oxidized in the following reaction?

    • Reaction: 2Mg + O2(g) → 2MgO
    • A) Mg
    • B) O2
    • C) MgO
    • D) both Mg and O2
    • Correct Answer: A) Mg

  3. Using the following balanced reaction, predict the number of moles of H2O if you use 2 moles of CH4 and 6 moles of O2?

    • CH4(g) + 2O2(g) → CO2(g) + 2H2O(g)
    • A) 4 mol
    • B) 6 mol
    • C) 8 mol
    • D) 2 mol
    • Correct Answer: A) 4 mol
Dissociation and Electrolytes

  1. Which of the following represents the dissociation of a strong electrolyte in water?

    • A) NH3(g) + H2O(l) → NH4OH(aq)
    • B) CH3OH(l) + H2O(l) → CH3OH(aq)
    • C) Na2SO4(s) + H2O(l) → 2Na+(aq) + SO4²⁻(aq)
    • D) C2H5OH(l) + H2O(l) → C2H5OH(aq)
    • Correct Answer: C) Na2SO4(s) + H2O(l) → 2Na+(aq) + SO4²⁻(aq)

  2. If you make saline solution by dissolving 13 g of Sodium chloride in 1 L of water, Sodium chloride is:

    • A) a solvent
    • B) a solute
    • C) a solution
    • D) a solid in water
    • Correct Answer: B) a solute
Reaction Rates and Molecular Forces

  1. Which of the following is not correct about the rate of the reaction?

    • A) The rate of reaction will increase by increasing temperature of the reaction
    • B) The rate of reaction will increase by decreasing temperature of the reaction
    • C) The addition of catalyst to the reaction will increase the rate of the reaction
    • D) Decreasing concentration of the reactants will decrease the rate of the reaction
    • Correct Answer: B) The rate of reaction will increase by decreasing temperature of the reaction

  2. Sugar and tea dissolved in water to make sweet tea, the predominant force between sugar and water in sweet tea is:

    • A) Hydrogen bonding
    • B) dipole-dipole
    • C) London dispersion
    • D) dipole-induced dipole
    • Correct Answer: A) Hydrogen bonding

  3. Concentrated solution of NaOH is used as an anti-clog solution in household cleaning purposes, the solution made by dissolving NaOH in water; the type of force between NaOH and water in making solution is:

    • A