Forensics C

[pikachu4919]

2022 Question Marathon Thread for Forensics C.

Question Marathons Explained

[corila]

Guys, why is there nothing posted here? Let's get this started

1. Let's start with some powder analysis. The flame test was yellow, very close to neutral in pH, crystal-shaped solid, and dissolves slowly in NaOH. What powder is this?

2. What is the charge of DNA?

3. In fingerprint development, which technique reacts with fats and oils to produce a print in the color orange?

[azboy1910]

Guys, why is there nothing posted here? Let's get this started

1. Let's start with some powder analysis. The flame test was yellow, very close to neutral in pH, crystal-shaped solid, and dissolves slowly in NaOH. What powder is this?

2. What is the charge of DNA?

3. In fingerprint development, which technique reacts with fats and oils to produce a print in the color orange?

This is my first time doing forensics so here goes nothing:

Click to Show Answer

1. sodium chloride
2. negative
3. iodine fuming

[corila]

That's correct!

[corila]

Guys, why is there nothing posted here? Let's get this started

1. Let's start with some powder analysis. The flame test was yellow, very close to neutral in pH, crystal-shaped solid, and dissolves slowly in NaOH. What powder is this?

2. What is the charge of DNA?

3. In fingerprint development, which technique reacts with fats and oils to produce a print in the color orange?

This is my first time doing forensics so here goes nothing:

Click to Show Answer

1. sodium chloride
2. negative
3. iodine fuming

that's correct!

[azboy1910]

I apologize for the long wait. Here are my questions:

1. What plastic is commonly used in plexiglass? What properties of this plastic make it good for this application?

2. How does the fiber tenacity of fibers used in jeans compare to those used in leggings? How do you know?

3. A blood sample agglutinates when tested with an Anti-D serum. Does this blood sample have a positive or negative blood type?

[terryokay]

I apologize for the long wait. Here are my questions:

1. What plastic is commonly used in plexiglass? What properties of this plastic make it good for this application?

2. How does the fiber tenacity of fibers used in jeans compare to those used in leggings? How do you know?

3. A blood sample agglutinates when tested with an Anti-D serum. Does this blood sample have a positive or negative blood type?

Click to Show Answer

1. PMMA. High hardness and high rigidity.
2. Cotton is generally used in Jeans while spandex. Spandex is extremely stretchy (anagrams for expand) and is used for comfort wear and fit. Cotton on the other hand is less stretchy and won't feel as comfortable. 
3. Positive
 

[azboy1910]

I apologize for the long wait. Here are my questions:

1. What plastic is commonly used in plexiglass? What properties of this plastic make it good for this application?

2. How does the fiber tenacity of fibers used in jeans compare to those used in leggings? How do you know?

3. A blood sample agglutinates when tested with an Anti-D serum. Does this blood sample have a positive or negative blood type?

Click to Show Answer

1. PMMA. High hardness and high rigidity.
2. Cotton is generally used in Jeans while spandex. Spandex is extremely stretchy (anagrams for expand) and is used for comfort wear and fit. Cotton on the other hand is less stretchy and won't feel as comfortable. 
3. Positive
 

That's correct!

[terryokay]

Here are my questions:
1) What bacteria is taq polymerase derived from?
2) Why do flame test emit colors. Describe in detail.
3) What fiber commonly undergoes mercerization?

[azboy1910]

Here are my questions:
1) What bacteria is taq polymerase derived from?
2) Why do flame test emit colors. Describe in detail.
3) What fiber commonly undergoes mercerization?

Click to Show Answer

1. Thermus aquaticus
2. Solids cause the flame to emit colors because the heat energy flame causes the electrons in the solid to enter an excited state, which causes them to move to energy levels farther from the nucleus. The difference in energy creates an emission of photons that fall under different areas of the visible light spectrum, which is responsible for the different colored flames that can be seen during a flame test.
3. cotton