I.

Calculate the freezing point and boiling point of a solution containing 14.2 gg of naphthalene (C10H8)(C10H8) in 111.0 mLmL of b

krek1111 [17]

Answer:

The freezing point of solution = -0.34 °C

The boiling point of solution = 82.98 °C

Explanation:

Step 1: Data given

Mass of naphthalene = 14.2 grams

Molar mass naphthalne = 128.17 g/mol

Volume of benzene = 111.0 mL

Density of benzene = 0.877 g/mL

Kf(benzene)=5.12°C/m

Freezing point benzene = 5.5 °C

Kb(benzene)=2.53°C/m

Boiling point benzene = 80.1 °C

Step 2: Calculate mass of benzene

Mass benzene = density * volume

Mass benzene = 0.877 g/mL * 111.0 mL

Mass benzene = 97.3 grams

Step 3: Calculate moles naphthalene

Moles naphthalene = mass naphthalene / molar mass napthalene

Moles napthalene = 14.2 grams / 128.17 g/mol

Moles naphthalene = 0.111 moles

Step 4: Calculate molality

Molality = moles naphthalene / mass benzene

Molality = 0.111 moles / 0.0973 kg

Molality = 1.14 molal

Step 5: Calculate freezing point of a solution

ΔT = i*kf*m

ΔT = 1 * 5.12 °C/m * 1.14 m

ΔT = 5.84 °C

ΔT = T(pure solvent) − T(solution)

The freezing point of solution = T pure - ΔT

5.5 - 5.84 = -0.34 °C

The freezing point is -0.34 °C

Step 6: Calculate boiling point of a solution

ΔT = i*kb*m

ΔT = 1 * 2.53 °C/m * 1.14 m

ΔT = 2.88 °C

ΔT = Tb (solution) - Tb (pure solvent)

The boiling point of solution = T pure + ΔT

The boiling point of solution = 80.1 °C + 2.88

The boiling point of solution = 82.98 °C

6 0

3 years ago

This is an example of a(n)

Sonbull [250]

That’s the correct answer I believe ^

5 0

3 years ago

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How much of Earth's atmosphere is made up of nitrogen and oxygen?

Archy [21]

<span>The right answer is the option B. Close to 99 percent. The atmosphere is a mixture of gases: nitrogen, oxygen, CO2, H2O, argon, among others. Nitrogen is about 78% and oxygen is about 21%, so they two together constitute about 99 percent of the Earth's atmosphere.</span>

3 0

3 years ago

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Which type of chemical reaction occurs in Ca+CI2 CaCI2

dimaraw [331]

Ca + Cl2 = CaCl₂

A synthesis <span>reaction.</span>

3 0

4 years ago

Determine the concentration of sulfuric acid that needed 47 mL of 0.39M potassium hydroxide solution to neutralize a 25 mL sampl

Ugo [173]

0.73 M is the concentration of sulfuric acid that needed 47 mL of 0.39M potassium hydroxide solution to neutralize a 25 mL sample of the sulfuric acid solution.

Explanation:

Data given:

Volume of the base = 47 ml

molarity of the base= 0.39 M

volume of the acid = 25 ml

molarity of the acid =?

For titration reaction between acid and base, the volume or molarity of any of the base or acid can be determined. The formula used:

Macid X Vacid = Vbase x Mbase

Macid = $\frac{Vbase X M base}{V acid}$

putting the values given in the rearranged equation above:

Macid = $\frac{0.39 x47}{25}$

= 0.73 M

The concentration of the sulphuric acid needed is 0.73 M.

3 0

4 years ago