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WorksheetsRevisiting Week 1and Week 2!
Total questions: 14
Worksheet time: 5mins
Amorphous
has axis of symmetry
has a fix cleavage plan
no sharp melting point
has a basic unit that is called morphs
During crystallization, stable forms are frequently obtained first, and then they transform into an unstable form
TRUE
FALSE
Which is the following, a type of crystal solvate?
Pseudomonas
Isotrophic
Anisotropic
Pseudopolymorphic
Crystalline solids have atoms that are arranged in an orderly repeating pattern.
TRUE
FALSE
Polymorphism occurs when the molecules rearrange themselves in two or more different ways in the crystal lattice
TRUE
FALSE
How to detect polymorphism?
X-ray machine
X-ray diffractometer
scanning electrone microscope
gas chromatography
How do amorphous substances differ from crystalline solids?
Amorphous substances have a lower density than crystalline solids.
Amorphous substances have a more ordered atomic structure than crystalline solids.
Amorphous substances do not have a regular, repeating pattern of atoms or molecules like crystalline solids do.
Amorphous substances have a higher melting point than crystalline solids.
What causes molecules to rearrange themselves in different ways in the crystal lattice?
Thermal energy or external forces
Electromagnetic radiation
Gravity
Chemical reactions
Describe the characteristics of a crystalline solid.
A crystalline solid is a solid material whose atoms are arranged in a highly ordered, repeating pattern extending in all three spatial dimensions.
A crystalline solid is a gas material whose atoms are arranged in a highly ordered pattern.
A crystalline solid is a liquid material whose atoms are arranged in a highly ordered pattern.
A crystalline solid is a solid material whose atoms are arranged in a random pattern.
Phase transformations in pharmaceutical dosage forms cause the following EXCEPT
caking in suspension
uniform formation of cream.
different disintegration time in tablets.
changes in crystal size in suspension.
The following statement is TRUE of X-ray diffraction analysis as a tool for solid state characterisation EXCEPT:
It is an interpretation of Bragg’s Law
It determines bond angles in molecules in solid state.
Amorphous samples result in sharp and narrow peak distribution.
It measures the average spacing between layers or rows of atoms.
Trigonal is used interchangeably with Rhombohedral
TRUE
FALSE
For gout patients, high levels of uric acid in the blood can contribute to the formation of crystals. The uric acid is in needle-like crystals, in the form of monosodium urate.
TRUE
FALSE
n λ=2d sin θ
Which is TRUE?
d = the distance between atomic blocks in a crystal theta
λ = the wavelength of the incident X-ray beam
n = an integral part of visual capacity of the beam
Θ = Bravis's angles/wavelength of incidence
