Covid Assignment 5: Miscellaneous Questions

 

Question 1

The sketch graph below shows the trend in first ionization energies for some elements in Periods two and three.

  1. Select, from the elements A to I, the one that has atoms with five p electrons.
  2. Select, from the elements A to I, which one is a member of group 3.
  3. Select, from the elements A to I, which one forms a +2 ion.
  4. Select, from the elements A to I, which one is likely to be very unreactive.
  5. Select, from the elements A to I, which one(s) normally forms four covalent bonds per atom.
  6. Name Element D.
  7.  What would the be the formula of the compound formed between element F and C.

Question 2

Draw the shape of:

  1. BF3
  2. CH3+
  3. CH3–
  4. SF3–
  5. BF2–
  6. NH2–
  7. ClF2–
  8. PF6–

Question 3

At a certain temperature, 0.860 mol of 

2SO_{3(g)}\rightleftharpoons 2SO_{2(g)}+O_{2(g)}

at equilibrium, 0.130 mol of 

Question 4

  1. If 10 mL of 0.004M AgNO3 is added to 10 mL of 0.0024M K2CrO4, is either Ag+ or CrO42- in stoichiometric excess? If so, which is in excess and by how much?
  2. The Ksp for BaCrO4 is 1.2 x 10-10, will BaCrO4 precipitate upon mixing 10 mL of 1 x 10-4M Ba(NO3)2 with 10 mL of 1.0 x 10-4M K2CrO4?

Question 5

The partition coefficient between ether and water for paracetamol is 10.5. You are given a sample containing 0.30g of acetanilide in 125mL of water.

  1. How much acetanilide would be removed from this solution after solvent extraction with 10mL of ether?
  2. How much acetanilide would be removed from this solution after solvent extraction with 50mL of ether?
  3. How much acetanilide would be removed from this solution after two consecutive solvent extractions with 25mL of ether?

Question 6

Find the ΔH for the reaction below, given the following reactions and subsequent ΔH values: C_2H_{2(g)} + 2.5O_{2(g)} \rightleftharpoons 2CO_{2(g)} + H_2O_{(g)}

C_2H_{6(g)} \rightarrow \rightleftharpoons C_2H_{2(g)} + 2 H_{2(g)} \: \: \: \: \: \Delta H = 283.5 kJ

H_{2(g)} + 0.5O_{2(g)} \rightarrow H_2O_{(g)} \: \: \: \: \Delta H=-213.7 kJ

2CO_{2(g)} + 3 H_2O_{(g)} \rightarrow C_2H_{6(g)} + 3.5O_{2(g)} \: \: \: \: \Delta H = 849 kJ

Question 7

For a reaction, the enthalpy change is –210 kJ, the entropy change is –170 J mol–1 K–1 and the temperature is 400 K. What is the free energy change, ∆G°, in kJ?

Question 8

List the compound from the following list which cannot be formed spontaneously from its elements at 298 K.