D - density: 40 mg/ml
V - volume: 175 ml
m - mass: ??
__________
d = m/V
m = V×d
m = 175×40
m = 7000 mg = 7 g
:•)
The molarity of a solution : 0.4 M
<h3>Further explanation</h3>
Given
0.2 moles of Potassium Oxide
500 ml of water = 0.5 L
Required
The molarity
Solution
Molarity is a way to express the concentration of the solution
Molarity shows the number of moles of solute in every 1 liter of solution or mmol in each ml of solution

Assume volume of solution = volume of water(addition of solution volume from volume Potassium Oxide is negligible
Input the value :
M = 0.2 : 0.5
M = 0.4
Explanation:
Relation between pressure of water and its droplet is as follows.
where, p = pressure of droplet
= water pressure in given temperature
=
M = Molecular Weight in Kg/Mol (0.018 for water)
r = radius in meters
= density of water in
(1000
)
R = ideal gas constant (8.31)
T = temperature in Kelvin
(a)
We will calculate the value of p as follows.
p =
=
= 26.8 torr
(b) And, vapor pressure of spherical water droplets of radius 2.0
or 
p =
=
= 25.2 torr
Answer is: <span>the charge of the iron in this compound is +2.
Atomic mass of iron is 55,8 g/mol.
Atomic mass of chlorine is 35,5 g/mol.
If compound is FeCl, molar mass would be 55,8 </span>g/mol + 35,5 g/mol = 91,3 g/mo, that is not correct.
If compound is FeCl₂, malar mass of compound would be:
55,8 g/mol + 2·35,5 g/mol = 126,8 g/mol, that is correct.
Oxaidation number of chlorine is -1.
D amplitude is the answer