Avogadro's number represents the number of units in one mole of any substance. This has the value of 6.022 x 10^23 units / mole. This number can be used to convert the number of atoms or molecules into number of moles. We calculate as follows:
237g CCl4 (1 mol / 153.81 g ) (6.022 x 10^23 molecules / 1 mol ) = 9.28x10^23 molecules
        
             
        
        
        
Answer:
the properties of three undiscovered elements  is the correct answer.
Explanation:
After he completed his work Mendeleev predicted the properties of the undiscovered elements.
In the year 1871, Dmitri Mendeleev predicted the detailed existence and the properties of the three elements that are undiscovered and he gained tremendous fame.
He left the gap in the table to put the elements which are not identified at that time and by glancing at the physical and chemical properties of an element next to the gap, Mendeleev could predict the properties of the not discovered elements.
 
        
             
        
        
        
Conductors are better than insulators to carry electric current because they give the electricity the ability to flow freely throughout circuits. This helps the insulator to do its job of containing the electric charge. Examples of this would be a tv plug - the rubber surrounding the TV plug helps to keep the conductors (wires) in place, thus helping to facilitate an electric charge.
 
        
             
        
        
        
Answer:
41.17g
Explanation:
We are given the following parameters for Flourine gas(F2).
Volume = 5.00L
Pressure = 4.00× 10³mmHG
Temperature =23°c
The formula we would be applying is Ideal gas law
PV = nRT
Step 1
We find the number of moles of Flourine gas present.
T = 23°C 
Converting to Kelvin
= °C + 273k
= 23°C + 273k
= 296k
V = Volume = 5.00L
R = 0.08206L.atm/mol.K
P = Pressure (in atm)
In the question, the pressure is given as 4.00 × 10³mmHg
Converting to atm(atmosphere)
1 mmHg = 0.00131579atm
4.00 × 10³ =
Cross Multiply
4.00 × 10³ × 0.00131579atm
= 5.263159 atm
The formula for number of moles = 
n = PV/RT
n = 5.263159 atm × 5.00L/0.08206L.atm/mol.K × 296K
n = 1.0834112811moles
Step 2
We calculate the mass of Flourine gas
The molar mass of Flourine gas = 
F2 = 19 × 2
= 38 g/mol
Mass of Flourine gas = Molar mass of Flourine gas × No of moles
Mass = 38g/mol × 1.0834112811moles
41.169628682grams
Approximately = 41.17 grams.