Download Crime Scene Investigation - Science with Ms. Dickson

Name ___________________________
Hour _____________
Date _____________
Crime Scene Investigation: Daniel DeMoy
Daniel DeMoy, a respected chemical researcher, has been found dead (poisoned!) in his home.
As a newly hired crime scene investigation team, you are some of the first to investigate the
chemical evidence.
Four pieces of evidence have been retrieved from the crime scene and related locations, each
pointing toward a different suspect. Each member of your team will be responsible for analyzing
one piece of evidence. As part of your analysis, you will first need to calculate the empirical and
molecular formulas for each compound in evidence. Then, you may access the Samples for
Comparison document to sort out the harmless substances from any potential poisons. With any
luck, a distinctive poison will point you toward Mr. DeMoy’s killer!
Your team will also be responsible for compiling the evidence into a presentation for the District
Attorney’s office so that an arrest can be made. This presentation may be in the form of a
PowerPoint, Glogster, or physical poster, and should include the following:
 A summary of the evidence found and analyses performed (you may adapt the Evidence
Analysis page) – including which team member analyzed which piece of evidence
 An explanation of what empirical and molecular formulas are, and why they enable you
to determine the identity of the poison
 Your recommendation for arrest
 At least two sentences justifying your recommendation (these will probably include
access to the poison and access to the victim)
Good luck!
Evidence Analysis
1. Unlabeled drug bottle.
Empirical formula: ____________
Molecular formula: _______________
Substance: ____________________
2. Half-empty cup.
Empirical formula: ____________
Molecular formula: _______________
Substance: ____________________
3. Partially empty bottle of acetaminophen.
Empirical formula: ____________
Molecular formula: _______________
Substance: ____________________
4. Victim’s research.
Empirical formula: ____________
Molecular formula: _______________
Substance: ____________________
Once you have analyzed each substance (determined the empirical and molecular formulas), you
may access the Samples for Comparison to identify each one and make your case: who did it,
and how?
Murderer:
Poison:
Evidence Summary
1. Unlabeled drug bottle (bathroom).
A 532.99 g sample of the drug was analyzed and found to contain 346.12 g carbon, 23.98 g
hydrogen, 108.52 g oxygen, and 54.36 g sulfur. The compound is found to have a
molecular mass of 314.38 g/mol.
2. Half-empty cup (coffee table).
The victim’s fingerprints were found on a half-empty cup on the coffee table amid the scent
of almonds. A 823.15 g liquid sample from the cup was found to contain 3.74% hydrogen,
44.43% carbon, and 51.83% nitrogen. The molecular mass was determined to be 27.03
g/mol.
3. Partially full bottle of acetaminophen tablets (bathroom).
Chemical analysis of one pill (1.454 g) found that it contains 0.924 g carbon, 0.0874 g
hydrogen, 0.134 g nitrogen, and 0.307 g oxygen. The molar mass of the drug is 151.18
g/mol. The bottle originally contained 50 tablets, and now contains 43.
4. Victim’s research (laboratory).
The victim was researching a new hydrocarbon with unknown health effects. A 453.28 g
sample of the compound was found to be 7.76% hydrogen, the rest carbon, and the
molecular mass is estimated at 117.171 g/mol.
The Victim
Daniel DeMoy is a 35-year-old research chemist at a respected university in Michigan. He was
found dead at his home at 9 pm last night. Prior to his death yesterday, Mr. DeMoy spent
most of the day at his laboratory at the university. He also had a cup of tea at his home with
a neighbor and colleague, Shay Lemarck. Mr. DeMoy suffered from severe osteoarthritis
and has been referred to as a “difficult patient,” causing frustration for his doctor and
devoted wife.
The Suspects
Aundrea DeMoy, the victim’s wife, has grown sick of her husband’s complaining. Lately, she
has been more inclined to give him extra tablets of Tylenol (acetaminophen) to keep him in
less pain – and thus quieter. Mrs. DeMoy claims that she worked late yesterday and
stopped at the grocery store before arriving home at 9 pm and finding her husband dead.
Shay Lemarck is a neighbor and colleague of Mr. DeMoy. The two are competing for a research
grant at the university and have never been close friends. Ms. Lemarck claims that she met
with Mr. DeMoy for tea to discuss a plan to collaborate on their upcoming grant
applications, that the meeting went well, and that she left him alive at 6 pm.
Kasey Hatterson is the victim’s research partner. Mr. Hatterson was recently seen arguing with
Mr. DeMoy about how to proceed with their upcoming grant application. Mrs. DeMoy
mentioned that her husband has caught Mr. Hatterson adjusting the fans in their research
lab, which could affect the inhalation rates of any toxic chemicals. Mr. Hatterson claims
that he did not see or speak to his partner after leaving the university at noon yesterday.
Dr. Fred Finch is the victim’s doctor. Dr. Finch has gained an unsavory reputation for
“disposing” of unwanted or needy patients – like Mr. DeMoy may have become. It is also
rumored that Dr. Finch is beginning research into hydrocarbons, and would have been a
new competitor for Mr. DeMoy’s research team. Dr. Finch claims he has not seen Mr.
DeMoy since a routine check-up last week, at which he prescribed another round of
osteoarthritis pain medication.
Samples for Comparison
1. Unlabeled drug bottle.
a.) The victim had been prescribed JointSpry, a harmless drug for osteoarthritis with a
molecular formula of C17H14O4S.
b.) Hypoprolactin is a related, hard-to-distinguish drug that can be toxic even in small
doses. The molecular formula of the toxic drug is C34H28O8S2.
2. Half-empty cup.
a.) The victim was partial to almond tea, flavored by a compound with a molecular formula
of H3C3N3.
b.) Hydrogen cyanide is a fast-acting, deadly poison known for its almond taste. The
molecular formula of hydrogen cyanide is HCN.
3. Partially full bottle of acetaminophen.
a.) Acetaminophen is toxic only in high doses. For poisoning to occur, the victim would
need to ingest at least 0.5 moles of acetaminophen in a short time.
4. Victim’s Research
a.) The victim claimed to be working on a newly discovered hydrocarbon with the
molecular formula C9H9.
b.) Benzene is a hydrocarbon that is toxic when inhaled in moderate to large doses.
Benzene has a molecular formula of C6H6.