Seven Lakes Invitational — Forensics

If the color for the Benedict's test is green, what is the percent of reducing sugar in the sample solution?

When ammonium chloride is burned, what fumes does it decompose into?

Which powder is used to put out grease fires?

Which of the following industrial processes was proposed during WW1 to enhance production of bombs?

Which of the following chemical reactions is the first step in Solvay synthesis?

Which of the following reagents DOES NOT test for reducing sugars? Select all that apply.

Which of the following statements best describes the charge-transfer complex in the reaction between cornstarch and iodine?

Which of the following explains why ammonium chloride is blue in Benedict's solution?

Which of the following explains why sodium carbonate has a higher pH than sodium bicarbonate?

Write the balanced equation of the reaction between calcium carbonate and hydrochloric acid. Include states of matter.

List the 3 components of Benedict's solution and their purpose.

What plastic is used as a glass substitute?

What plastic dissolves in acetone (nail polish remover)?

You test one of the plastics found at the crime scene and discover it starts to melt under heat and can be reshaped. The plastic is a(n) ____.

Which of the following statements best describes injection molding?

Which of the following best describes the process of addition polymerization?

Condensation polymers grow through step-growth polymerization. Very simply, this means that the polymer is able to grow from both ends. A polymerization reaction can be represented through a rate law. Select all of the following concentrations that could be measured to represent the rate law for a condensation polymerization reaction. Assume the concentrations for all can be measured reliably.

Dr. CK's student makes the following claims: "Nylon 6 is polymerized by a step-growth process. This means it releases a by-product during polymerization." Are they correct?

Bisophenol A is formed through a condensation reaction between which two compounds? What byproduct is released by the reaction? You may use the reference provided on the suspect sheet/image sheet.

Given that the degree of polymerization of a sample of PMO (definitely a real polymer) is 9,132 and the molecular weight of its monomer is 67 g/mol, find the polymer's average molecular weight. Show work for your final answer.

Using your knowledge of crystalline and amorphous solids, explain which of the two exhibits a definite melting point and why.

What percent of hair weight does the cortex make up?

Given a hair with a medulla diameter of 48 µm and total diameter of 95 µm, what is the medullary index and where does the hair come from?

Which of the following is the correct classification of a bat hair cuticle?

Human eyelashes are what type of hair?

What cross sectional shape does straight hair have?

Is hair a type of individual or class evidence? Why?

Explain how these two parts work together to give spandex's characteristic elastic property.

Who invented the first microfiber?

What are secondary structures of silk proteins?

What is the shape of the cross section of linen?

Which of these fiber shapes usually has the highest luster?

A fiber is generally characterized by a continuous strand that is ____ times longer than it is thick.

Which of the following explains what mercerization does to fibers?

What is a visible light microspectrophotometer used for in the context of fibers in a forensic laboratory?

A mass spectrum of an unknown sample found at the crime scene is on your image sheet.

(b) What is the identity of the compound? Write the full chemical name. Possible structures can be found on the image sheet.

If the velocity of a particle is moving out of the page and the magnetic field is also going out of the page, what is the direction of the force on the particle?

What are the three main parts of a mass spectrometer?

The following are ranked in the most likely order from lowest relative abundance to highest relative abundance on a mass spectrometer: primary carbocations, secondary carbocations, tertiary carbocations. How was this order determined? Hint: think about charges.

In a mass spectrum, the element chlorine shows a double peak. Explain why this is and identify the ratio of the first peak to the second peak.

Snyder polarity index, or P′, is a method used to order compounds based on their polarity. Higher values of P′ indicate that the solvent is more polar. It accounts for a variety of factors, including dipole moments and acidity/basicity, to create a more complex picture of a solvent's polarity. Which of the following solvents would have the highest value of P′?

What type of evidence is Mitochondrial DNA?

If the root of the hair isn't available to harvest DNA, what other form of DNA can be obtained from the hair shaft?

While checking a new sequencing protocol, an analyst observes a DNA region that under high-salt conditions shifts to a left-handed helical formation. Which DNA form is most consistent with these findings?

A forensic lab sequences a degraded mitochondrial fragment and finds that the original codon CAA (glutamine) has mutated to UAA. What type of mutation is this?

Find the Henry Classification number of the set of fingerprints (Diagram B) pictured on the suspect information/image sheet.

Iodine fuming can be used for fingerprinting on all of the following surfaces EXCEPT:

What does the CLPE stand for?

When ninhydrin detects the amino acid asparagine, what color does it turn?

Why do fingerprints remain after getting a first degree burn?

Name the five layers of the epidermis from the bottom to the top. All or nothing.

A blood spatter at the crime scene has a width that is a third of its length. What is the angle of impact?

If Bobby was given a blood transfusion with O- blood, the "universal donor", his blood would still react to O-. This is very dangerous, yet many people overlook this problem. How could the ABO test be fixed to accommodate all blood types, including Bobby's? Explain why your solution would work.

Shards of glass was found at the crime scene. A ray of light enters the glass at 40° relative to the normal and exits at 25.7°. What is the refractive index of the glass? Show work for full points.

Bulletproof glass is bulletproof to a certain extent. This is because it is more flexible than normal glass which prevents it from immediately shattering. Why is this?

What Forensics plastic can be found in bulletproof glass?

Use the fracture image provided on the suspect information/image sheet. What is the sequence of the fractures?

Which soil characteristic is most strongly indicated by a dark brown color?

A soil sample has a brown clay layer (argillic horizon) and ochric epipedon near the surface and the pH is about 6.2. Based on these features listed above, what is most likely the soil order?

Generally, we can predict the time of death of a corpse based on the stages of blowflies. However, it sometimes varies due to outside factors. What factor is most influential in the development of blowflies (and other insects in general)? Explain why this occurs.

What are instars in forensic entomology? List each instar stage of a blowfly and provide the time period and characteristics of each which can reveal clues about a crime scene.