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4 years ago

how many moles of a nonvolatile, nonelectrolyte solute are required to lower the freezing point of 1000 grams of water by 5.58

Chemistry

1 answer:

Ivan4 years ago

5 0

Answer:

Explanation:

Using freezing point depression formula,

ΔTemp.f = Kf * b * i

Where,

ΔTemp.f = temp.f(pure solvent) - temp.f(solution)

b = molality

i = van't Hoff factor

Kf = cryoscopic constant

= 1.86°C/m for water

= (0 - (-5.58))/1.86

= 3.00 mol/kg

Assume 1 kg of water(solvent)

= (3.00 x 1)

= 3.00 mol.

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Which formulas represent two polar molecules?

Tresset [83]

The correct answer is shown in option 3. Water and hydrochloric acid are polar molecules. These molecules are polar because of the presence of bonds that are partially ionic or polar covalent bonds. Other examples are hydrogen fluoride and ammonia.

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4 years ago

What is the potential energy of the bowling ball as it sits on top of the building?

Tju [1.3M]

Answer:

Potential energy is energy due to an object's height above the ground.

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3 years ago

Ka/KbMIXED PRACTICE108.Calculate the [H3O+(aq)], the pH, and the % reaction for a 0.50 mol/L HCN solution. ([H3O+(aq)] = 1.8 x 1

NeTakaya

Answer:

a) [H₃O⁺] = 1.8x10⁻⁵ M

b) pH = 4.75

c) % rxn = 3.5x10⁻³ %

Explanation:

a) The dissociation reaction of HCN is:

HCN(aq) + H₂O(l) ⇄ H₃O⁺(aq) + CN⁻(aq)

0.5 M - x x x

The dissociation constant from the above reactions is given by:

$Ka = \frac{[H_{3}O^{+}][CN^{-}]}{[HCN]} = 6.17 \cdot 10^{-10}$

$6.17 \cdot 10^{-10} = \frac{x*x}{(0.5 - x)}$

$6.17 \cdot 10^{-10}*(0.5 - x) - x^{2} = 0$

By solving the above quadratic equation we have:

x = 1.75x10⁻⁵ M = 1.8x10⁻⁵ M = [H₃O⁺] = [CN⁻]

Hence, the [H₃O⁺] is 1.8x10⁻⁵ M.

b) The pH is equal to:

$pH = -log[H_{3}O^{+}] = -log(1.75 \cdot 10^{-5} M) = 4.75$

Then, the pH of the HCN solution is 4.75.

c) The % reaction is the % ionization:

$\% = \frac{x}{[HCN]} \times 100$

$\% = \frac{1.75 \cdot 10^{-5} M}{0.5 M} \times 100$

$\% = 3.5 \cdot 10^{-3} \%$

Therefore, the % reaction or % ionization is 3.5x10⁻³ %.

I hope it helps you!

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3 years ago

Elements in a given period of the periodic table contain the same number of

leva [86]

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3 years ago

Silicon reacts with carbon dioxide to form silicon carbide sic and silicon dioxide

andrew-mc [135]

The question is incomplete, here is the complete question:

Silicon reacts with carbon dioxide to form silicon carbide and silicon dioxide. Write the balanced chemical equation.

<u>Answer:</u> The balanced chemical equation is written below.

<u>Explanation:</u>

Every balanced chemical equation follows law of conservation of mass.

A balanced chemical equation is defined as the equation in which total number of individual atoms on the reactant side is equal to the total number of individual atoms on product side.

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By Stoichiometry of the reaction:

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3 years ago