Unit 5 - Practice Quiz

1 Which of the following represents the basic structural unit of the silica sheet in silicate clays?

2 What is the ratio of tetrahedral to octahedral sheets in the crystal structure of Kaolinite?

3 Which phenomenon is primarily responsible for the permanent negative charge in 2:1 silicate clays?

4 Which cation typically dominates the interlayer space of Illite, preventing expansion?

5 According to the Lyotropic series, which of the following cations is most strongly adsorbed by soil colloids?

6 The Cation Exchange Capacity (CEC) of a soil is best defined as:

7 Which clay mineral typically has the highest Cation Exchange Capacity (CEC)?

8 What is the standard unit for expressing Cation Exchange Capacity (CEC) in the SI system?

9 The swelling and shrinking behavior of Montmorillonite (Smectite) is caused by:

10 Calculate the Base Saturation percentage if a soil has a CEC of and the sum of exchangeable basic cations () is .

11 In the silicon tetrahedron, the central silicon ion () is surrounded by how many oxygen ions?

12 Which source of charge is considered 'pH-dependent'?

13 Anion Exchange Capacity (AEC) generally increases when:

14 Which of the following is considered an 'acidic cation' in the context of base saturation?

15 Buffering capacity in soils refers to:

16 Active acidity in soil is defined as:

17 Which soil component contributes most significantly to pH-dependent charge (variable charge)?

18 Which equation correctly represents the stoichiometry of cation exchange?

19 In the aluminum octahedron, the coordination number of Aluminum is:

20 Which of the following clay minerals is non-expanding?

21 The 'Point of Zero Charge' (PZC) is the pH at which:

22 Which mechanism creates a permanent charge in Montmorillonite?

23 Reserve (or potential) acidity is typically _____ than active acidity.

24 If a soil has a high buffering capacity, adding lime will:

25 Which colloid type is known as 'Amorphous' (non-crystalline)?

26 Which of the following is an oxide clay commonly found in highly weathered tropical soils?

27 The specific surface area is highest in which of the following clays?

28 The conversion factor between and is:

29 Dispersion of soil colloids is primarily promoted by which cation?

30 Flocculation is the process of:

31 Chlorite is structurally similar to vermiculite but contains an extra layer of:

32 Which functional group is primarily responsible for the CEC of soil organic matter?

33 In a 2:1 clay mineral, the '2' refers to:

34 A soil with a Base Saturation of 20% would likely have a pH that is:

35 Which law states that the ratio of cations on the exchange surface is proportional to the ratio of their activities in the soil solution?

36 Why does Kaolinite have a much lower CEC than Smectite?

37 Which cation exchange reaction represents the process of acidification?

38 The 'Oscillation Volume' refers to:

39 Which of the following creates a 'tetrahedral sheet'?

40 What is the primary process responsible for the release of ions from Aluminum () in soil solution?

41 Which soil texture typically has the lowest buffering capacity?

42 Isomorphous substitution usually occurs during:

43 If the concentration of in the soil solution increases, what happens to the adsorbed on the colloid?

44 The negative charge on humus is primarily:

45 Anions like Nitrate () and Chloride () are generally:

46 Which cation is most effective at causing soil particles to disperse, leading to poor structure?

47 A 2:1 clay with high lattice charge located in the tetrahedral sheet, limiting expansion, describes:

48 The 'Complementary Ion Effect' describes how:

49 Generally, the CEC of a soil usually ___ with an increase in soil organic matter.

50 When measuring soil pH with water, the result represents: