Forensic Quiz 5

Question 1

Compare and Identify Metals

Answer 1

1.Major Composition of Metals:i.d by spectrophotometry
2.Trace Elements that serve as fingerprints in comparing one metal against the other
-neutron activation
-bombard that piece of metal with neutrons then they measure the energy of gamma rays emitted

Question 2

How do you i.d

Answer 2

I.d substance by there selective absorption of different wave lengths of light

Question 3

paint

Answer 3

a type of coating designed to cover a surface for the purpose of imparting color and for protection

Question 4

Major Chemical Components of Paint

Answer 4

a binder(additives, drying agent,delusterant) (dissolved in solvents) and 1 or more pigment-inorganic substances

Question 5

Other Types of Coating(they themselves not paint)

Answer 5

1. Shellac
   2.Varnish
   3.Stains

Question 6

Shellac

Answer 6

coating made from an insect extract(the lac) dissolved in methyl alcohol(used to protect wood)(don’t give color)

Question 7

Varnish

Answer 7

a solution of film formers and resin dissolved in solvent(protect wood)(don’t give color)

Question 8

Stains

Answer 8

contain soluble dyes/pigments in a solvent(it colors the wood but does not protect it)

Question 9

Types of Paint

Answer 9

1.Automotive Paint
2.Structural Paint
3.Artistic Paint
4.Other special purpose paints

Question 10

Automotive Paint

Answer 10

most important type of paint in forensic work

Question 11

Structural Paint

Answer 11

building walls and objects

Question 12

Artistic Paint

Answer 12

oldest type of paint derived from naturally occurring oils and pigments

Question 13

Other Special Purpose Paints

Answer 13

-used to color and seal concrete floors
-flourescent paint(road signs)
-skid resistant paint

Question 14

How are cars painted?

Answer 14

1.Two coats of rust proofing
2.primer
3.topcoat-imports color to the car
4.clear coat-acrylic(or urethane based, no pigments, imparts extra durability and uv resistance

Question 15

Collection of Paint Evidence(of car)

Answer 15

1.Chip/Flake-contains most or all of the layers of paints(forensically yields most info)
2.Smear(streak marks)

Question 16

Analysis of Paint

Answer 16

A.Physical Properties-color layer sequence (microspectrphotometer)
B.Chemical Properties

Question 17

Chemical Properties of Paint

Answer 17

-solubility
-chromatography-analyzing the binders and dyes
-scanning electron microscopy (only viable method for smear paint)with energy dispersive x ray analysis(SEMIEDX)-pigments

Question 18

soil

Answer 18

crushed rocks and minerals mixed with delayed plant and animal matter(humus)

Question 19

Comparing soil

Answer 19

1.color
2.size and shape of crushed rocks and minerals
3.ph-acid/base(alkaline) 1-14(ph scale)
4.Density Gradient
5.% of humus-chromotography
6.looking at moisture content(%)

Question 20

matter

Answer 20

anything that has mass and occupies space

Question 21

element

Answer 21

simplist substance known provides building blocks where all matter is composed

Question 22

Periodic Table

Answer 22

grouping elements into specific groups color codes and placed with other similar properties

Question 23

atom

Answer 23

smallest particle of an element that can exist and still retains its identity

Question 24

CO2

Answer 24

elements in carbon dioxid:carbon and oxygen)
-1 atoms of carbon and 2 atoms of oxygen

Question 25

compound

Answer 25

when two or more elements combined to form a new material that is different in its physical and chemical properties from it elemental components

Question 26

Physical Property of Substance

Answer 26

describes the behavior of substance without the alteration of the substance composition through a chemical reaction ex.color volume mass boiling point texture and melting point

Question 27

Physical Change of a Substance

Answer 27

-this does not change the makeup of mater(not chemical identity -change in size, form of matter,shape

Question 28

Chemical Property

Answer 28

describes the behavior of a substance when its reacts or combines with other substance to form a new substance

Question 29

Chemical Change

Answer 29

change in substance in there internal makeup it is not easily reversed back to original substance/formex burning/rusting/rotting

Question 30

States of Matter/Process

Answer 30

1. Solid to convert to liquid it melts 2.Liquid to covert to gas it is vaporization 3.Gas to convert Plasma through ionization

Question 31

Solid

Answer 31

a definite shape/size/dimensions that can be measured, rigid not easily change, molecular bonding is strong

Question 32

liquid

Answer 32

definite volume, no definite shape, takes form of a container, bonding of molecules glide and slide, gives state of matter fluidity(not rigid)

Question 33

Gas

Answer 33

no definite volume of shape

Question 34

Plasma

Answer 34

very hot

Question 35

Glass Composition

Answer 35

composed of sand(silicon oxides) mixed with various metal oxides

Question 36

Mixed Metal oxides

Answer 36

1.soda(sodium carbonate)-added to mixture to lower melting point 2.lime(calcium dioxide)-addes to prevent the glass from dissolving in water

Question 37

Types of oxide glass

Answer 37

1.Soda Lime Glass 2.Tempered Glass(when breaking becomes fragment does not shatter 3.laminated glass(ex.buildings like skyscrapers) provides strength and sound insulatuin

Question 38

Important Physical Properties for Forensic Characterization of Glass

Answer 38

1.Reflection Index=velocity of light(air)/velocity of light(medium) 2.Density=mass(g)/volume(mL) 3.Types pf Glass 4.Fraction Feature of Glass(can speculate series of impacts