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OlgaM077 [116]
2 years ago
14

A solution is prepare using 45.2 g of an unknown (nonelectrolyte) dissolved in 476.4 g of water. The freezing point depression

Chemistry
1 answer:
Ray Of Light [21]2 years ago
6 0

Answer:

94.4g/mol is molar mass of the unknown

Explanation:

Based on the freezing point depression equation:

ΔT = Kf*m*i

<em>Where ΔT is the depression in freezing point (1.87°C)</em>

<em>Kf is freezing point depression constant of water (1.86°Ckg/mol)</em>

<em>And i is Van't Hoff factor (1 for nonelectrolyte solutes)</em>

<em />

Replacing:

1.87°C = 1.86°CKg/mol*m*i

1.005mol/kg solvent = m

Using the mass of the solvent we can find the oles of the nonelectrolyte:

1.005mol/kg solvent * 0.4764kg = 0.479moles

Molar mass is defined as the ratio between mass of a substance in grams and moles, that is:

45.2g / 0.479mol =

<h3>94.4g/mol is molar mass of the unknown</h3>
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The heat needed to melt 10.0 grams of ice at -10°C until it is water at 10°C is 3,969.5 J. (approx= 3963J).

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Sensible heat is defined as the amount of heat that a body absorbs or releases without any changes in its physical state.

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<h3>What is Latent heat? </h3><h3 />

Latent heat is defined as the energy required by a quantity of substance to change state.

When this change consists of changing from a solid to a liquid phase, it is called heat of fusion and when the change occurs from a liquid to a gaseous state, it is called heat of vaporization.

In this case, the heat Q that is necessary to provide for a mass m of a certain substance to change phase is equal to

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C= specific heat capacity of ice= 2.108 J/gK

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ΔT= T(final)– T(initial) = 0 °C – (-10 °C)= 10 °C= 10 K

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The specific heat of melting of ice is 334 J/g, the heat needed to melt 10 grams of ice is

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C= specific heat capacity of liquid water is 4.187 J/gK

M= 10 g

ΔT= T(final) – T(initial) = 10 °C – 0 °C= 10 °C= 10 K because being a temperature difference, the difference is the same in °C and K.

Q(3) = 4.187×10×10

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Total heat required= Q1 + Q2 + Q3

Total heat required= 210.8 J + 3,340 J + 418.7 J

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learn more about heat :

brainly.com/question/16818736

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