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.
Homogeneous Mixture:
<span>It may be mistaken for a pure substance.
</span><span>It can be separated using distillation
</span>
Heterogeneous Mixture:
<span>Its components are visible
</span><span>It can be separated using distillation.
Concrete is an example of this kind of mixture.
</span>
Hope this helps!
Answer:
The concentration of the solution is 1.364 molar.
Explanation:
Volume of perchloric acid = 29.1 mL
Mass of the solution = m
Density of the solution = 1.67 g/mL

Percentage of perchloric acid in 48.597 solution :70.5 %
Mass of perchloric acid in 48.597 solution :
= 
Moles of perchloric acid = 
In 29.1 mL of solution water is added and volume was changed to 250 mL.
So, volume of the final solution = 250 mL = 0.250 L (1 mL = 0.001 L)


The concentration of the solution is 1.364 molar.
Answer : The atom with the same number of neutrons as
is, 
Explanation :
- The given atom is,

Atomic mass number = 12
Atomic number = 6
Atomic number = Number of protons = Number of electrons = 6
Number of neutrons = Atomic mass number - Atomic number = 12 - 6 = 6
Now we have to determine the number of neutrons in the given options.
- In atom,

Atomic mass number = 9
Atomic number = 4
Atomic number = Number of protons = Number of electrons = 4
Number of neutrons = Atomic mass number - Atomic number = 9 - 4 = 5
- In atom,

Atomic mass number = 11
Atomic number = 5
Atomic number = Number of protons = Number of electrons = 5
Number of neutrons = Atomic mass number - Atomic number = 11 - 5 = 6
- In atom,

Atomic mass number = 13
Atomic number = 6
Atomic number = Number of protons = Number of electrons = 6
Number of neutrons = Atomic mass number - Atomic number = 13 - 6 = 7
- In atom,

Atomic mass number = 14
Atomic number = 7
Atomic number = Number of protons = Number of electrons = 7
Number of neutrons = Atomic mass number - Atomic number = 14 - 7 = 7
Therefore, the atom with the same number of neutrons as
is, 
Sodium is Highly reactive. It reacts with like everything