Basic Science ,Novel Science

1. Chemistry in Our Lives
Chemistry and Chemicals
Dr.Gurumeet C Wadhawa
Assistant Professor ,Department
of Chemistry
Rayat Shikshan Santa's Veer
Wajekar Asc College,Phunde

2. Chemistry is the study of substances in terms of
Composition What a material it made of
StructureHow the elementary particles are put together
Properties The characteristics of the material
Reactions How it behave with other substances
What is chemistry?

3. Chemical reactions happen when
• a car is started
• tarnish is removed from silver
• fertilizer is added to help plants
grow
• food is digested
• electricity is produced from
burning natural gas
• rust is formed on iron nails

4. Everything in our lives from materials
to life involve chemistry
• glass (SiO2)n
• metal alloys
• chemically treated water
• plastics and polymers
• baking soda, NaHCO3
• foods
• fertilizers and pesticides
• living beings

5. Chemicals in Toothpaste

6. What is Organic Chemistry?
• Organic chemistry is the study of carbon compounds.
– Organic compounds have carbon AND hydrogen
– Carbon Dioxide is NOT organic
• The versatility and stability of carbon’s molecular
structures provides the enormous range of
properties of its compounds.
• Carbon can bond to other carbons
– Reason for the degree of structural complexity

7. Ridiculous Complexity
Palytoxin – made by species
of some species of seaweed
and coral
Synthesized by Kishi, et. al.
at Harvard in 1994

8. Organic Chemistry
• Carbon
– Has 4 valence electrons
– Makes 4 covalent bonds to fill its octet
• Can include double and triple bonds
– Hydrocarbon
• Compound with only carbon and hydrogen

9. Organic Chemistry in Everyday Life
• Smells & tastes: fruits, fish, mint
• Medications: aspirin, Tylenol, decongestants, sedatives, insulin
• Addictive substances: caffeine, nicotine, alcohol, narcotics
• Hormones/Neurotransmitters: adrenaline, dopamine, serotonin
• Food: carbohydrates, protein, fat, vitamins
• Genetics: DNA, RNA
• Consumer products: plastics, nylon, rayon, polyester

10. Organic Materials
• Addition to previous notes
– Before, it was stated that covalent compounds
were mostly liquid/gas at room temp
– This is primarily for binary compounds (2
elements)
– More complicated structures can be solid at room
temp

11. General Formulas
• Alkanes
– Contains only single bonds
– Cx H2x+2
• Alkenes
– Contains at least one double bond
• Alkynes
– Contains at least one triple bond
• Alkenes and Alkynes are more reactive than
alkanes

12. Saturation
• Saturated: a carbon chain contains as many
hydrogens as possible.
• Saturated compounds contain only single C-H
bonds. Alkanes are saturated.
• Unsaturated means that a carbon chain
contains at least one multiple (double or
triple) bond.
– Alkene = double bond
– Alkyne = triple bond

13. Hydrocarbons
IUPAC
name
Molecular
Formula
Structural
Formula
Boiling
Point (°C)
Methane CH4 CH4 -161.5
Ethane C2H6 CH3CH3 -88.6
Propane C3H8 CH3CH2CH3 -42.1
Butane C4H10 CH3(CH2)2CH3 -0.5
Pentane C5H12 CH3(CH2)3CH3 36.1
Hexane C6H14 CH3(CH2)4CH3 68.7
Heptane C7H16 CH3(CH2)5CH3 98.4
Octane C8H18 CH3(CH2)6CH3 125.7
Nonane C9H20 CH3(CH2)7CH3 150.8
Decane C10H22 CH3(CH2)8CH3 174.1
.

14. Structure and Physical Properties
• Larger molar mass = higher boiling point
– Bigger compound – higher boiling point
Methane
16 g/mol
-161.5oC
Ethane
30 g/mol
-88.6oC
Propane
44 g/mol
-42.1oC
Butane
58 g/mol
-0.5oC

15. Petrochemicals
• Simple, small hydrocarbons are
petrochemicals
– Chemicals isolated from crude oil (petroleum)
• Octane – used in gasoline
• Propane – used in grills, heaters, etc.
• Butane – lighter fluid

16. Functional Groups
• Functional
Group –
group of
atoms which
control how
the molecule
reacts

17. Polymers
Polymers
Large molecules with many, many repeating
units, made from smaller molecules
n
CH2 CH2
Polyethylene

18. Polymers
• Nylon, Kevlar, and PVC are other examples of
manmade polymers
Nylon
PVC (polyvinyl chloride)

19. Natural Polymers
Proteins RNA

20. Natural Polymers
DNA
Polysaccharides

21. Pharmaceuticals
• Most pharmaceuticals are complex, organic
molecules
• Can be natural or manmade
aspirin penicillin Acetaminophen
(aka Tylenol)

22. Terms To Know
• Hydrocarbon
• Alkane
• Alkene
• Alkyne
• Saturated
• Unsaturated
• Petrochemicals
• Functional Group
• Polymers

23. Skills To Master
• Differentiating alkanes, alkenes, and alkynes
• Differentiating saturated and unsaturated
compounds
• Differentiating natural polymers and
manmade polymers
• Recognizing common pharmaceuticals

24. Physical and Chemical
Changes
Change is COOL!

25. Physical vs. Chemical Changes
Physical changes occur when substances or
objects undergo a change without changing into
another substance
Chemical changes are changes substances undergo
when they become new or different substances.

26. Physical vs. Chemical Changes
 Chemical changes happen on a molecular level
http://www.chem4kids.com/files/matter_chemphys.html
 Physical change – object’s identity remains the same
 Chemical change – object’s identity changes
 Usually involves energy (like heat) and states of
matter.
Remember that after a:

27. Physical Change
- Involves heat
Melting of ice cream is an
example of a physical change.
YOUR TURN: Can you think of other examples of
physical changes?
Image available at
http://www.icecreamclubonline.com/

28. Chemical Change
At the molecular level: The
wax molecule changes to
carbon dioxide and water
molecules.
Burning of a candle is an
example of a chemical
change.
Image available at Colin Baird, “Chemistry in Your Life”. 2nd ed.,
(ISBN 0-7167-7042-3) New York: W.H. Freeman, 2006.

29. Tarnishing of silver
Corrosion (rusting) of iron
Other examples of chemical changes
Image available at
http://www.photographersdirect.com/buy
ers/stockphoto.asp?imageid=1263140
Image available at
http://www.mrmartinweb.com/bicycle.html

30. Other examples of chemical changes
Can you think of another term for chemical
changes?
YOUR TURN: Can you think of other examples of
everyday life chemical reactions?
Chemical change = chemical reaction

31. Can you identify the following changes as
physical or chemical?
Crushing a plastic bottle
Melting of ice
Digestion of food
Formation of frost on your window
Milk turns sour
Fireworks

32. Collecting and Preserving Evidence
Physical and chemical changes are sometimes
involved in the collection of physical evidence from
a crime scene
Reference: M. Johll, “Investigating Chemistry: A Forensic Science Perspective.”
W.H.Freeman: New York, 2007. p. 26.
Ex. Latent fingerprints (invisible to the naked eye) are
treated with chemicals to become visible (= chemical
change)
Developing latent fingerprints
Image source:
http://www.clpex.com/images/Articles/R
TX/s-Dsc_0025.jpg

33. Collecting and Preserving Evidence
Ex. Bloody clothes are dried out to prevent the blood from
decomposing.
 Identify the underlined words above as either a
physical or chemical change.
Reference: M. Johll, 2007, p. 25
Question: Why are evidence collected in separate containers?

34. Chemical changes are more difficult to identify than physical
changes
http://www.usoe.k12.ut.us/curr/Science/sciber00/8th/matter/
sciber/chemchng.htm
Identifying chemical changes
 smoke, and
 Can’t see changes in molecules
 But we can look for observable signs
 color change
 bubbling and fizzing
 light production
 presence of heat

35. Everyday life chemical changes/reactions
 Acid-base reactions
Q. Do you know where in our body do we have acids?
Q. Can you give some examples of acids? Bases?
Q. Can you give an example of acid-base reaction?

36. Everyday life chemical changes/reactions
 Oxidation reactions
Q. Can you tell which gas is used or produced during
oxidation?
Q. What could be an observable sign of oxidation
reaction?

37. ACID and BASES
of everyday life

38. Image available at C. Snyder, “The Extraordinary Chemistry of
Ordinary Things,” 4th ed. Wiley, 2003.

39. Image available at C. Baird and W. Gloffke, “Chemistry In Your Life.” New
York: Freeman, 2003. (p. 437)
Acidic soil Alkaline (basic) soil

40. Acidic and basic are two extremes that describe chemicals, just like hot and cold are
two extremes that describe temperature.
Mixing acids and bases can cancel out their extreme effects; much like mixing hot and
cold water can even out the water temperature.
A substance that is neither acidic nor basic is neutral.
http://www.epa.gov/acidrain/measure/ph.html

41. Highly corrosive!
Highly corrosive!
Remember:
Low pH = high acidity
Image available at
http://www.phsciences.com/about_
ph/ph_scale.asp