Answer:
The 8-hour TWA exposure for the employee is 101 ppm and it exceeds the OSHA PEL of 100 ppm for ethylbenzene.
Explanation:
The TWA for 8 hours is calculated by the sum of airbone concentrations multiplied by the time it has been exposed to that period. The total is divided by 8 which refers to the 8 hours total the employee has been exposed.
TWA = (125x2+88x2+112x2.5+70x1.5)/8.
The OSHA PEL is a known number for every compound and it can be find in PEL tables. In the case of ethylbenezene, it is 100 ppm.
Answer:
(1) It shows arrangement of elements based on modern periodic law.
(2) There are 18 vertical columns known as groups.
(3) There are 7 horizontal rows known as periods.
The answer would be millimeters
so answer choice d
Answer:
Two electrons.
Explanation:
Calcium is the element of second group and forth period. The electronic configuration of Calcium is - 2, 8, 8, 2 or 
There are 2 valence electrons of Calcium.
Iodine is the element of seventeenth group and fifth period. The electronic configuration of Iodine is - 2, 8, 18, 18, 7 or ![[Kr]4d^{10}5s^25p^5](https://tex.z-dn.net/?f=%5BKr%5D4d%5E%7B10%7D5s%5E25p%5E5)
There are 7 valence electrons of iodine.
Calcium iodide, 
is formed when 2 valence electrons of calcium are loosed and they are gained by 2 atoms of iodine.
