Answer:
2 E16 Hz or 2 * 10^16 Hz
Explanation:
The formula to determine frequency is f = c / λ.
f = frequency
c = speed of light
λ = wavelength
f = 3E8 / 1.5E-8
f = 2E16
This makes sense because UV light exists roughly
between 8E14 Hz and 3E16 Hz ----- 2E16 Hz falls in that range
For an aqueous solution of MgBr2, a freezing point depression occurs due to the rules of colligative properties. Since MgBr2 is an ionic compound, it acts a strong electrolyte; thus, dissociating completely in an aqueous solution. For the equation:
ΔTf<span> = (K</span>f)(<span>m)(i)
</span>where:
ΔTf = change in freezing point = (Ti - Tf)
Ti = freezing point of pure water = 0 celsius
Tf = freezing point of water with solute = ?
Kf = freezing point depression constant = 1.86 celsius-kg/mole (for water)
m = molality of solution (mol solute/kg solvent) = ?
i = ions in solution = 3
Computing for molality:
Molar mass of MgBr2 = 184.113 g/mol
m = 10.5g MgBr2 / 184.113/ 0.2 kg water = 0.285 mol/kg
For the problem,
ΔTf = (Kf)(m)(i) = 1.86(0.285)(3) = 1.59 = Ti - Tf = 0 - Tf
Tf = -1.59 celsius
D I have a good feeling about d
Answer:
Mass = 90.28 g
Explanation:
Given data:
Mass of Ca(OH)₂ = ?
Volume of solution= 1.5 L
Molarity of solution = 0.81 M
Solution:
First of all we will calculate number of moles.
Molarity = number of moles / volume in L
by putting values,
0.81 M = Number of moles / 1.5 L
Number of moles = 0.81 M × 1.5 L
Number of moles = 1.22 mol
Mass of Ca(OH)₂ in gram:
Mass = number of moles × molar mass
Mass = 1.22 mol × 74.09 g/mol
Mass = 90.28 g
