The items are answered below and are numbered separately for each compound.
The freezing point of impure solution is calculated through the equation,
Tf = Tfw - (Kf)(m)
where Tf is the freezing point, Tfw is the freezing point of water, Kf is the freezing point constant and m is the molality. For water, Kf is equal to 1.86°C/m. In this regard, it is assumed that m as the unit of 0.25 is molarity.
1. NH4NO3
Tf = 0°C - (1.86°C/m)(0.25 M)(2) = -0.93°C
2. NiCl3
Tf = 0°C - (1.86°C/m)(0.25 M)(4) = -1.86°C
3. Al2(SO4)3
Tf = 0°C - (1.86 °C/m)(0.25 M)(5) = -2.325°C
For boiling points,
Tb = Tbw + (Kb)(m)
For water, Kb is equal to 0.51°C/m.
1. NH4NO3
Tb = 100°C + (0.51°C/m)(0.25 M)(2) = 100.255°C
2. NiCl3
Tb = 100°C + (0.51°C/m)(0.25 M)(4) = 100.51°C
3. Al2(SO4)3
Tb = 100°C + (0.51°C/m)(0.25 M)(5) = 100.6375°C
Answer : The correct option is, (A) 0.109 M 
Solution : Given,
Mass of = 17 g
volume of solution = 974 ml
Molar mass of = 159.609 g/mole
Molarity : It is defined as the number of moles of solute present in one liter of solution.
Formula used :
where,
w = mass of (solute)
M = molar mass of
= volume of solution in liter
Now put all the given values in the above formula, we get the molarity of solution.
Therefore, the molarity of the solution is, 0.109 M
Answer:
E = 6.27 × 10⁻²³ Joules
Explanation:
E = h (Plancks constant) × f (frequency)
(Plancks constant = 6.63 × 10⁻³⁴ J×s)
f = λ × c (used to find frequency so you can satisfy energy equation)
*Have to find wavelength in meters to multiply by speed of light*
1. f = (3.15 × 10⁻⁷ m) × (3 × 10⁸ m/s)
2. f = 9.45 × 10¹⁰ s
3. E = (6.63 × 10⁻³⁴ J×s [Plancks constant]) × (9.45 × 10¹⁰ s)
E = 6.27 × 10⁻²³ Joules
