Answer:
Collecting residue samples.
Explanation:
All the other given options are equally important on the exploration of a bomb aftermath.
The most important task is the collection of residue samples since it needs highly skilled personel to collect accurate samples for later on analysis.
Identification of meaningful collection areas is a technical skill that requires the most experienced team memebers.
Explanation:
Relation between entropy change and specific heat is as follows.

The given data is as follows.
mass = 500 g,
= 24.4 J/mol K
= 500 K,
= 250 K
Mass number of copper = 63.54 g /mol
Number of moles = 
= 
= 7.86 moles
Now, equating the entropy change for both the substances as follows.
= ![7.86 \times 24.4 \times [500 -T_{f}]](https://tex.z-dn.net/?f=7.86%20%5Ctimes%2024.4%20%5Ctimes%20%5B500%20-T_%7Bf%7D%5D)

= 750
So,
= 
- For the metal block A, change in entropy is as follows.

= ![24.4 log [\frac{375}{500}]](https://tex.z-dn.net/?f=24.4%20log%20%5B%5Cfrac%7B375%7D%7B500%7D%5D)
= -3.04 J/ K mol
- For the block B, change in entropy is as follows.

= ![24.4 log [\frac{375}{250}]](https://tex.z-dn.net/?f=24.4%20log%20%5B%5Cfrac%7B375%7D%7B250%7D%5D)
= 4.296 J/Kmol
And, total entropy change will be as follows.
= 4.296 + (-3.04)
= 1.256 J/Kmol
Thus, we can conclude that change in entropy of block A is -3.04 J/ K mol and change in entropy of block B is 4.296 J/Kmol.
Answer:
The ionization energy of each successive element generally decreases
Explanation:
The ionization energy increases in the periods of the periodic table and decreases in the groups. If the atom is very small, we will need a lot of energy to release the electron, while if the atom is larger the energy will be greater.
When HCl reacts with a metal, hydrogen gas will be evolved. To test this gas, insert a burning splinter into the outlet of gas, the flame will be extinguished with a pop sound. This will confirm the gas is hydrogen.