To calculate the number of molecules, we can simply use this rule:
number of molecules = number of moles x Avogadro's number
In this problem, we have:
number of moles = 4.56 moles
Avogadro's number is a constant = 6.02 x 10^23
Substituting in the above equation, we can calculate the number of molecules as follows:
number of molecules = 4.56 x 6.02 x 10^23
= 2.74512 x 10^24 molecules
The control group in this experiment is the one with just distilled water. It is plain so they can use it to compare the other tests against.
Answer: The empirical formula is 
Explanation:
If percentage are given then we are taking total mass is 100 grams.
So, the mass of each element is equal to the percentage given.
Mass of Br= 58.37 g
Mass of F = (100-58.37) = 41.63 g
Step 1 : convert given masses into moles.
Moles of Br=
Moles of F =
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For Br = 
For F = 
The ratio of Br: F= 1 : 3
Hence the empirical formula is 
sodium cloride is salt created from sodium Na and chlorine Ci
Na-sodium Ca- calcium
Ci-chlorine FL- flerovium
Ca- calcium Br-bromine
H- hydrogen He-helium
They are help together by the strong nuclear force from neutrons