chap 10 (gun powder)

Question 1

– because of its inherent defects modern ammunition plants abandoned the use of this

Answer 1

Black Powder

Question 2

– is the most widely used propellant. It can either be single base propellant or double propellant. modern

Answer 2

Smokeless Powder

Question 3

– possibly the oldest known explosive. It is consisting of an intimate mixture of charcoal – 15%, sulfur – 10% and potassium or sodium nitrate 75%.

Answer 3

Black Powder

Question 4

It is consisting of Cellulose Nitrate or Glyceryl Nitrate combined with Cellulose Nitrate and some stabilizers. Among the stabilizers used are Nitrates, Bichromates and Oxalates. Some of the organic stabilizers are Nitrobenzene, Graphite and Vaseline. Stabilizers are added to reduce side reactions

Answer 4

Smokeless Powder

Question 5

a weapon with________ barrel will deposit residues over a larger area than a weapon having a five inches barrel even though they are fired at the same distance and with the same type of ammunition.

Answer 5

2 inches

Question 6

– affects the speed with which powder burns. Powder having lesser amount of moisture will burn more rapidly and completely within a given time yielding greater amount of residue.

Answer 6

Humidity

Question 7

The burned residues are partially burned particles may escape around the breech of the gun and implanted on the exposed surface of the hand firing the gun and the presence of this particles serves as a basis for the _________

Answer 7

diphenylamine – paraffin test (DPA – Paraffin Test).

Question 8

– a test to determine whether a person fired a gun or not with bare hands.

Answer 8

Diphenylamine Test

Question 9

– the taking of the cast to extract the nitrates embedded or implanted in the skin.

Answer 9

Paraffin Test

Question 10

– the chemical aspect of the test. It determines the presence and distribution of nitrates.

Answer 10

Diphenylamine Test

Question 11

Visible Result of diphenylamine test: ____________that develop when nitrates come in contact with the diphenylamine reagent.

Answer 11

Deep blue specks

Question 12

1. The test is not specific for nitrates since the role of nitrate is simply oxidizing agent. The test cannot determine the source of nitrate.
2. There are other substances which contain nitrate oxidizing agents that are not in the ordinary course of life like fertilizers, explosives, tobacco, firecrackers, urine, cosmetics and detergents.
3. In general persons do not have nitrates or other oxidants on their hands as a matter of common occurrence.

Answer 12

Limitation of the Diphenylamine – Paraffin Test:

Question 13

In cases involving shooting incidents where paraffin test is required, the person suspected to have fired a gun should be subjected to diphenylamine - paraffin test immediately and in no case should it be postponed________ hours after shooting.

Answer 13

seventy – two (72)

Question 14

It is possible to detect nitrates as late as ________even though the hands have been washed. In the Philippines the period is reduced to_________only due to excessive perspiration.

Answer 14

three days

two days