The hydrogen and oxygen atoms that combine to form water molecules are bound together by covalent bonds. The electron from the hydrogen splits its time between the incomplete outer shell of the hydrogen atom and the incomplete outer shell of the oxygen atom.

6 0

3 years ago

Assuming complete dissociation of the solute, how many grams of KNO3 must be added to 275 mL of water to produce a solution that

iragen [17]

Answer:

108.43 grams KNO₃

Explanation:

To solve this problem we use the formula:

ΔT = Kf * b * i

Where

ΔT is the temperature difference (14.5 K)

Kf is the cryoscopic constant (1.86 K·m⁻¹)

b is the molality of the solution (moles KNO₃ per kg of water)

and i is the van't Hoff factor (2 for KNO₃)

We solve for b:

14.5 K = 1.86 K·m⁻¹ * b * 2

b = 3.90 m

Using the given volume of water and its density (aprx. 1 g/mL) we calculate the necessary moles of KNO₃:

275 mL water ≅ 275 g water

275 g /1000 = 0.275 kg

moles KNO₃ = molality * kg water = 3.90 * 0.275

moles KNO₃ = 1.0725 moles KNO₃

Finally we convert KNO₃ moles to grams, using its molecular weight:

1.0725 moles KNO₃ * 101.103 g/mol = 108.43 grams KNO₃

5 0

2 years ago