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3 years ago

What is the freezing point of a solution prepared by dissolving 50.0g of glycerin in 200g of ethanol?

2 answers:

7 0

When a solute is added to a solvent, some properties are affected and these set of properties are called colligative properties. Freezing point depression calculation is used for this type of problem. Calculations are as follows:

ΔT(freezing point) = (Kf)m
ΔT(freezing point) = 1.86 °C kg / mol (50.0/92.09 mol / .200 kg)
ΔT(freezing point) = 5.04 °C 
Tf - T = 5.04 °C 
T = -5.04 °C

Serjik [45]3 years ago

4 0

Answer:

-120 °C

Explanation:

The freezing point depression is calculated as follows:

ΔT = Kf*m

where ΔT is the difference between the freezing point of the pure solvent and from the solution; kf is a constant (equal to 2 °C/m for ethanol); and m is the molality of the solution.

moles of solute = (50 g)/(92.09 g/mol) = 0.54 mol

molality of the solution = moles of solute / kg of solvent

molality of the solution = 0.54 mol/ 0.2 kg = 2.7 m

ΔT = 2*2.7 = 5.4 °C

The freezing point of ethanol is -114.6 °C, then the freezing point of the solution is -114.6 °C - 5.4 °C = -120 °C

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3 years ago

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aivan3 [116]

Answer:

1.18x10⁸L of SO₂ and 2.36x10⁸L of H₂S

Explanation:

The balanced reaction is:

8SO₂(g) + 16H₂S(g) → 16H₂O(l) + 3S₈(s)

To solve this question we must find the moles of S₈ in 4.50x10⁵kg. With these moles and the reaction we can find the moles of SO₂ needed to react (Twice these moles = Moles Of H₂S needed). Using PV = nRT we can find the volume of the gas required:

Moles S₈ - molar mass: 256.52g/mol-

4.50x10⁵kg = 4.50x10⁸g * (1mol / 256.52g) =

1.75x10⁶ moles S₈

Moles SO₂:

1.75x10⁶ moles S₈ * (8mol SO₂ / 3mol S₈) = 4.68x10⁶ moles SO₂

Moles H₂S:

4.68x10⁶ moles SO₂ * 2 = 9.36x10⁶ moles H₂S

The volume could be obtained as follows:

PV = nRT

V = nRT / P

V is volume in liters

n are moles: 4.68x10⁶ moles SO₂ and 9.36x10⁶ moles H₂S

R is gas constant = 0.082atmL/molK

T is absolute temperature = 22°C + 273.15 = 295.15K

P is pressure = 0.961atm

Replacing:

Volume SO₂ and H₂S:

4.68x10⁶ moles * 0.082atmL/molK * 295.15K / 0.961atm =

9.36x10⁶ moles H₂S * 0.082atmL/molK * 295.15K / 0.961atm =

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2 years ago

Describe how the catalyst, zymase speeds up the reaction shown

Vlad1618 [11]

Describe how the catalyst, zymase speeds up the reaction shown

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2 years ago

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Mila [183]

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