Answer:
Option C. 1.60x10^26 molecules
Explanation:
Avogadro's hypothesis proved that that 1 mole of any substance contains 6.02x10^23 molecules.
From the above, we understood that 1 mole of CCl4 contains 6.02x10^23 molecules.
If 1 mole of CCl4 contains 6.02x10^23 molecules,
then, 265 moles of CCl4 will contain = 265 x 6.02x10^23 = 1.60x10^26 molecules
From the calculation made above, 265 moles of CCl4 contains 1.60x10^26 molecules.
Hi!
To make 500 mL of a 1,500 M solution of NaCl you'll require
43,83 g
To calculate that, you will need to use a conversion factor to go from the volume of the 1,500 M solution to the required grams. For this conversion factor, you'll use the definition for Molar concentration (M=mol/L) and the molar mass of NaCl. The conversion factor is shown below:

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Explanation:
At each reflecting surface (benzene and glass) there will be 180 degree phase change.
Now, for constructive interference the optical path in benzene is
.
Formula to calculate thickness of a benzene thin film is as follows.
Optical path length through benzene (
) = 
Hence, substituting the given values into the above formula as follows.
Optical path length through benzene = 
d = 
=
=
(as 1 nm = 
= 204.9 m
Thus, we can conclude that minimum thickness of benzene is 204.9 m.
The volume of concentrated HCl : 2.073 ml
<h3>Further explanation</h3>
Given
37% HCl by mass; density 1.19 g/mL
Required
The volume of concentrated HCl
Solution
Conversion to molarity :
37% x 1.19 g/ml =0.4403 g/ml
g/ml to mol/L :
=0.4403 g/ml x 1000 ml/L : 36.5 g/mol
=12.06 mol/L
or we can use formula :

Dilution formula :
M₁V₁=M₂V₂
12.06 M x V₁ = 0.1 M x 0.25 L
V₁ = 0.0021 L = 2.073 ml
The number of protons must differ between two different elements