Lewis Structures are life
Supplemental Instruction
Iowa State University / Leader: / Kia
Course: / CHEM 177
Instructor: / Anand
Date: / April 6th, 2017

ACS Practice questions

1. 

2.  Which element is most likely to form a triple bond? Pb F N S

Practice Questions

  1. How does is bond length related to bond order (ie single vs double vs triple bonds)
  1. Lewis Structures – Watch for formal charges, resonance, and exceptions

  1. PO3-2
  1. ClF4+
  1. SF6-1
  1. FNO2
  1. TeO3
  1. NO

  1. Calculate the dipole moment for HF (bond length 0.917 Å), assuming that the bond is completely ionic. Remember and 1 “unit charge” = 1.60 x 10-19 C
  1. Estimate the standard enthalpy of formation of ammonia given the following average bond enthalpies in kJ: D(N-H), 391; D(N-N), 163; D(N=N), 418; D(N=N), 941; D(H-H), 436.
  1. Based on Lewis structures, predict the ordering, from shortest to longest, of N-O bonds lengths in NO+, NO2-1, NO3-1.

Challenge Questions

  1. Draw the lewis structure(s) for a compound which contains 52.2% C, 13.1 % H, and 34.7 % O and has an approximate molar mass of 46 g?
  1. The element bismuth (Bi, atomic number 83) is the heaviest member of group 5A. A salt of the element, bismuth subsalicylate, is the active ingredient in Pepto-Bismol, an over the counter medication for gastric distress.
  2. What accounts for the general increase in atomic radius going down the group 5A elements?
  1. Bi2O3 is a basic oxide. Write a balanced chemical equation for its reaction with dilute nitric acid. If 6.77 g of Bi2O3 is dissolved in dilute acidic solution to make 0.500 L of solution, what is the molarity of the solution of Bi3+ ion?
  1. The density of Bi at 25 degrees C is 9.808 g/cm3. How many Bi atoms are present in a cube of the element that is 5.00 cm on each edge? How many moles of the element are present?