The masses of the 2 most
common isotopes of Cl are 35 and 37. Therefore we can formulate 3 possible
masses of Cl2:
<span>
35 + 35 = 70
35 + 37 = 72
37 + 37 = 74
<span>However, Cl 35 is the most common isotope of chlorine of the
two therefore it is the most probable that two Cl 35 atoms will combine, so 70
is the most common among all.
</span></span>
Oceanic crust would be on top, being less dense and doesn't have as much water in it. Old oceanic crust is usually on the bottom, and filled with water. It is more dense.
Hey there!:
Copper plating on Zinc will occur via this simple reaction:
Cu²⁺ + 2 e⁻ ⇌ Cu
When a species gains electron, it is reduced. Its oxidation state is decreased. For example, in the above reaction Cu2+ gained 2 electron to get reduced to Cu. Its oxidation state changed from +2 to 0. Hence it is a reduction reaction.
So, the correct answer is :
The copper II ions gain two electrons and are reduced.
Answer B
Hope this helps!
Answer : The final temperature of the metal block is, 
Explanation :

As we know that,

.................(1)
where,
q = heat absorbed or released
= mass of aluminum = 55 g
= mass of water = 0.48 g
= final temperature = ?
= temperature of aluminum = 
= temperature of water = 
= specific heat of aluminum = 
= specific heat of water= 
Now put all the given values in equation (1), we get
![55g\times 0.900J/g^oC\times (T_{final}-25)^oC=-[0.48g\times 4.184J/g^oC\times (T_{final}-25)^oC]](https://tex.z-dn.net/?f=55g%5Ctimes%200.900J%2Fg%5EoC%5Ctimes%20%28T_%7Bfinal%7D-25%29%5EoC%3D-%5B0.48g%5Ctimes%204.184J%2Fg%5EoC%5Ctimes%20%28T_%7Bfinal%7D-25%29%5EoC%5D)

Thus, the final temperature of the metal block is, 
Answer
Avogadro's number: One mole of any substance contains 6.022×10²³ molecules
Explanation
While finding the number of moles of oxygen molecules present in 3.65 moles of Na2SO4 the conversion factor used would be Avodagro's number, which is
One mole of any substance contains 6.022×10²³ molecules.