Assuming complete dissociation of the solute, how many grams of KNO3 must be added to 275 mL of water to produce a solution that freezes at −14.5 ∘C? The freezing point for pure water is 0.0 ∘C and Kf is equal to 1.86 ∘C/m .

Answer : The mass of KNO₃ added must be,

Explanation : Given,

Molal-freezing-point-depression constant for water =

Volume of water = 275 mL

Molar mass of KNO₃ = 101.1 g/mole

First we have to calculate the mass of water.

Density of water = 1.00 g/mL

Now we have to calculate the mass of KNO₃

Formula used :  

where,

= change in freezing point

= freezing point of solution =

= freezing point of water =

i = Van't Hoff factor = 2  (for KNO₃ electrolyte)

= freezing point constant for water =

m = molality

Now put all the given values in this formula, we get

Therefore, the mass of KNO₃ added must be,

because u need two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei to form isotopes.

so since they all have the same shape? i mean maybe because m& m and reeses are both chocolates

so whats the answer tell me