Answer:
Explanation:
The formula for sodium is Na. It does not form a molecule in some way.
1 mol Na = 6.02*10^23 atoms
3.91 mol = x Cross multiply
x = 3.91 * 6.02 * 10^23
x = 23.65 * 10^23
x = 2.365 * 10^24
Scientific notation is always expressed as a number 1 ≤ x < 10
Answer/Explanation:
Chlorine and Fluorine are in the Halogen family. The elements in the Halogen family are:
Fluorine (F)
Chlorine (Cl)
Bromine (Br)
Iodine (I)
Astatine (At)
Tennessine (Ts)
Hydrogen (H) is a nonmetal
Oxygen (O) is a nonmetal
Lithium (Li) is an alkaline metal.
Be-beryllium have 2 electrons and it is in the 2 nd period
Answer: The volume of 0.640 grams of 
gas at Standard Temperature and Pressure (STP) is 0.449 L.
Explanation:
Given: Mass of gas = 0.640 g
Pressure = 1.0 atm
Temperature = 273 K
As number of moles is the mass of substance divided by its molar mass.
So, moles of (molar mass = 32.0 g/mol) is as follows.
Now, ideal gas equation is used to calculate the volume as follows.
PV = nRT
where,
P = pressure
V = volume
n = no. of moles
R = gas constant = 0.0821 L atm/mol K
T = temperature
Substitute the values into above formula as follows.
Thus, we can conclude that the volume of 0.640 grams of gas at Standard Temperature and Pressure (STP) is 0.449 L.
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