Week 6: X-Ray Fluorescence, X-Ray Diffraction & X-Ray Absorption

Question 1

What does XRF stand for?

Answer 1

X-Ray Fluorescence

Question 2

True or False: XRF is used primarily for qualitative analysis.

Answer 2

False

Question 3

What is the main principle behind XRF?

Answer 3

It measures the characteristic fluorescent X-rays emitted from a material when it is excited by a primary X-ray source.

Question 4

Fill in the blank: XRF is commonly used in ________ analysis.

Answer 4

elemental

Question 5

What does XRD stand for?

Answer 5

X-Ray Diffraction

Question 6

What type of information does XRD provide?

Answer 6

It provides information about the crystal structure, phase identification, and other structural properties of materials.

Question 7

True or False: XRD can be used to analyze both crystalline and amorphous materials.

Answer 7

False

Question 8

What type of radiation is used in XRD?

Answer 8

X-rays

Question 9

What is the main purpose of X-Ray Absorption Spectroscopy (XAS)?

Answer 9

To study the electronic structure and local environment of specific elements in a sample.

Question 10

Fill in the blank: XAS is sensitive to the ________ of elements in a sample.

Answer 10

oxidation state

Question 11

What does the term ‘absorption edge’ refer to in XAS?

Answer 11

The energy at which a specific element’s core electrons can be excited to unoccupied states.

Question 12

Multiple choice: Which technique can provide information about the coordination environment of an element? A) XRF B) XRD C) XAS

Answer 12

C) XAS

Question 13

True or False: XRF can detect elements down to parts per million (ppm) levels.

Answer 13

True

Question 14

What is a common application of XRF?

Answer 14

Environmental monitoring and analysis of metals in soil and water.

Question 15

What is the primary detector used in XRD?

Answer 15

A scintillation counter or a CCD detector.

Question 16

Fill in the blank: In XRD, the ________ angle is critical for determining the crystal structure.

Answer 16

Bragg

Question 17

What is one advantage of using XRF over other analytical techniques?

Answer 17

It is non-destructive and requires minimal sample preparation.

Question 18

Multiple choice: Which technique is best suited for determining the mineral composition of a sample? A) XRF B) XRD C) Both A and B

Answer 18

C) Both A and B

Question 19

What does the term ‘phase identification’ mean in the context of XRD?

Answer 19

Determining the specific crystalline phases present in a material based on its diffraction pattern.

Question 20

True or False: X-Ray Absorption Spectroscopy requires a vacuum environment.

Answer 20

True

Question 21

What is an application of XRD?

Answer 21

Analyzing the crystallinity of polymers.

Question 22

What type of samples can XRF analyze?

Answer 22

Solid, liquid, and powder samples.

Question 23

Fill in the blank: In XRF, the primary source of X-rays is typically an ________ tube.

Answer 23

X-ray

Question 24

What is the role of the monochromator in XAS?

Answer 24

To select specific wavelengths of X-rays to probe the sample.

Question 25

Multiple choice: Which technique provides quantitative elemental analysis? A) XRF B) XRD C) XAS

Answer 25

A) XRF

Question 26

What is the significance of the ‘EXAFS’ region in XAS?

Answer 26

It provides information about the local structure around the absorbing atom.

Question 27

True or False: The resolution of XRD is influenced by the size of the crystallites in the sample.

Answer 27

True

Question 28

What is one limitation of XRF?

Answer 28

It cannot detect light elements effectively, such as lithium or beryllium.

Question 29

Fill in the blank: XRD uses the ________ principle to analyze crystalline materials.

Answer 29

Bragg’s

Question 30

What is the typical range of elements that XRF can detect?

Answer 30

From sodium (Na) to uranium (U).

Question 31

Multiple choice: In which situation would XAS be particularly useful? A) To determine the composition of a solid sample B) To investigate the local environment of a specific element C) To measure the weight of a sample

Answer 31

B) To investigate the local environment of a specific element