4. Chemistry

Question 1

Provides a classification and labeling of hazardous chemical

Answer 1

GHS: Globally Harmonized System

Question 2

pH (definition and scale)

Answer 2

Potential of Hydrogen, which is a logarithmic scale which measures H ion activity
0-6: acidic
7: neutral
8-14: alkaline

Question 3

¿When a solution is considered highly corrosive?

Answer 3

pH less than 2 (highly acidic) or greater than 12.5 (highly basic)

Question 4

Formula of pH & pOH

Answer 4

Acidic: pH = -log (H+)
H+: concentration of hydrogen ion (M)
(H+) = 10^(-pH)

Alkaline: pH = 14 - pOH
pOH = -log (OH-)
OH-: concentration of hydroxide ion (M)

Question 5

Flash points of flammable and combustible liquids

Answer 5

CL > 100 ºF and < 200 ºF
FL <100 ºF

Question 6

Formula of PPM regarding %LEL (lower explosive limit)

Answer 6

PPM = %LEL x 10,000
e.g.: for 1.4% LEL -> 1.4 * 10,000 = 14,000 ppm

Question 7

ACGIH

Answer 7

American Conference of Governmental Industrial Hygienists

Question 8

Percent concentration to PPM

Answer 8

PPM = % * 10,000

Question 9

PPM to concentration in mg/m3

Answer 9

Conc. mg/m3 = (molecular weight of substance g/mol)x(PPM) / 24.45

Question 10

Detectors: PID ; FID

Answer 10

PID: Photo Ionization Detector
FID: Flame Ionization Detector

Question 11

TWA:definition and formula

Answer 11

Time Weighted Average: average exposure over an eight-hour day (in a 40-hour work week).
TWA = (C1T1 + C2T2 + … + Cn*Tn) / (T1 + T2 + … + Tn)
C: concentrations of the chemical
T: lengths of time over which concentrations are measured (sum 8 hours?)

Question 12

Formula to exposure to chemical mixtures

Answer 12

E = C1/TLV1 + C2/TLV2 + … + Cn/TLVn
- C: concentrations of each chemical
- TLV: threshold limit value for each chemical

Question 13

; a measurement of a chemical determinant in the biological media of those exposed and is an indicator of the uptake of a substance.

Answer 13

Biological Exposure Index (BEI)