Answer:
I am sure that the C one is correct
The compound NaCI is an example of a salt. Salt is formed from a neutralization action of an acid and a base. From the type of reaction itself, we can say that the pH should be neutral or at pH 7.0. No matter what type of acid or base is used.
Answer: 1) "cohension" ;
2) "liquid" .
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Mercury-199 is composed of 80 protons, 119 neutrons, and 80 electrons.
First, you need to find:
One mole of

is equivalent to how many grams?
Well, for this you have to look up the periodic table. According to the periodic table:
The atomic mass of Calcium Ca = 40.078 g (See in group 2)
The atomic mass of <span>Chlorine Cl = 35.45 g (See in group 17)
</span>
As there are two atoms of Chlorine present in

, therefore, the atomic mass of

would be:
Atomic mass of

= Atomic mass of Ca + 2 * Atomic mass of Cl
Atomic mass of

= 40.078 + 2 * 35.45 = 110.978 g
Now,
110.978 g of

= 1 mole.
75.9 g of

=

= 0.6839 moles.
Hence,
The total number of moles in 75.9g of

= 0.6839 moles
According to <span>Avogadro's number,
1 mole = 1 * </span>

molecules
0.6839 moles = 0.6839 *

molecules =

molecules
Ans: Number of molecules in 75.9g of
=
molecules
-i