Answer:
m = 3 moles/kg
Explanation:
This is a problem of freezing point depression, and the formula or expression to use is the following:
ΔT = i*Kf¨*m (1)
Where:
ΔT: Change of temperature of the solution
i: Van't Hoff factor
m: molality of solution
Kf: molal freezing point depression of water (Kf = 1.86 °C kg/mol)
Now, the value of i is the number of moles of particles obtained when 1 mol of a solute dissolves. In this case, we do not know what kind of solution is, so, we can assume this is a non electrolyte solute, and the value of i = 1.
Let's calculate the value m, which is the molality solving for (1):
m = ΔT/Kf (2)
Finally, let's calculate ΔT:
ΔT = T2 - T1
ΔT = 0 - (-5.58)
ΔT = 5.58 °C
Now, let's replace in (2):
m = 5.58/1.86
<em>m = 3 moles/kg</em>
<em>This is the molality of solution.</em>
<em>The other data of mass, can be used to calculate the molecular mass of this unknown solid, but it's not asked in the question.</em>
The answer is C which is PbSo
Answer:амьсгал боогдов гэж найдаж байна
Explanation:
Fluorine - Seven electrons of it's own.
Lithium would give up one electron, so there for, fluorine is then left with eight.
Answer:
Some formulas for calculating mole are
Mole = Mass/ Molar mass
Mole = no of particles / avogadros constant
NB : no of particles can be no of atoms , no of ions , or no of molecules 2. Avogadros number or constant = 6.02 times 10 ^23
so we will be using the second formula
Mole = no of particles / avogadros constant
Mole = 5.03 x 10 ^23/6.02 x10^23
Mole = 8.355x10^45
hope it helps :)
Explanation:
