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3 years ago

Hydrofluoric acid, hf, has a ka of 6.8 × 10−4. what are [h3o+], [f−], and [oh−] in 0.710 m hf?

Chemistry

1 answer:

STALIN [3.7K]3 years ago

6 0

Answer:

[H₃O⁺] = [F⁻] = 2.2 x 10⁻² M. & [OH⁻] = 4.55 x 10⁻¹³.

Explanation:

For a weak acid like HF, the dissociation of HF will be:

[H₃O⁺] = [F⁻].

Ka = 6.8 x 10⁻⁴, C = 0.710 M.

∴ [H₃O⁺] = √Ka.C = √(6.8 x 10⁻⁴)(0.710) = 2.197 x 10⁻² M ≅ 2.2 x 10⁻² M.

∵ [H₃O⁺][OH⁻] = 10⁻¹⁴.

<em>∴ [OH⁻] = 10⁻¹⁴/[H₃O⁺]</em> = 10⁻¹⁴/(2.2 x 10⁻²) = <em>4.55 x 10⁻¹³.</em>

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What type of bonding holds the atoms in an h2o molecule together?

Ivanshal [37]

Covalent bond two non metals

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3 years ago

Write a balanced half-reaction for the reduction of bismuth oxide ion to bismuth ion in basic aqueous solution. Be sure to add p

Butoxors [25]

Answer:

$3H_2O+(Bi^{5+}O_3)^-\rightarrow Bi^{3+}+6OH^-$

Explanation:

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In this case, according to the required half-reaction, we start by setting it up from bismuth (V) oxide ion to bismuth (III) ion:

$BiO_3^-\rightarrow Bi^{3+}$

Thus, next realize that the oxidation state of Bi in BiO3^- is 5+ because oxygen is 2- (-2*3+x=-1;x=-1+6;x=+5), so we obtain:

$(Bi^{5+}O_3)^-\rightarrow Bi^{3+}$

Thereafter, we realize three water molecules are needed on the right in order to balance the oxygens and consequently 6 hydrogen atoms on the left to balance hydrogen:

$6H^++(Bi^{5+}O_3)^-\rightarrow Bi^{3+}+3H_2O$

Now, since the balance is is basic media, we add six molecules of hydroxide ions in order to produce water with the hydrogen ones:

$6OH^-+6H^++(Bi^{5+}O_3)^-\rightarrow Bi^{3+}+3H_2O+6OH^-\\\\6H_2O+(Bi^{5+}O_3)^-\rightarrow Bi^{3+}+3H_2O+6OH^-\\\\6H_2O-3H_2O+(Bi^{5+}O_3)^-\rightarrow Bi^{3+}+6OH^-$

Then, we accommodate the waters to obtain:

$3H_2O+(Bi^{5+}O_3)^-\rightarrow Bi^{3+}+6OH^-$

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3 years ago

A 10-liter container has 2 moles of oxygen at a pressure of 92 kpa. The effective speed (rms) of the oxygen molecules in the gas

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The effective speed (rms) of the oxygen gas is 293.68 m/s.

<h3></h3><h3>What is Root-mean-square velocity?</h3>

Root mean square velocity is the square root of the mean of squares of the velocity of individual gas molecules

$v_{rms}=\sqrt[]{\frac{3RT}{M} }$

<em>where </em>R = universal gas constant

M = molar mass of the gas in kg/mol

T = temperature in Kelvin

According to the ideal gas law,

PV = nRT

RT = $\frac{PV}{n}$

Substitute in the rms velocity formula,

$v_{rms} = \sqrt[]{\frac{3PV}{nM} }$

P = 92 kPa, V = 10 L, n = 2 moles and M = 32 x 10⁻³ kg/mol

$v_{rms} = \sqrt[]{\frac{3\times92\times10}{2\times32\times10^-^3} }$

=293.68 m/s

Thus, the effective speed (rms) of O₂ gas is 293.68 m/s.

Learn more about Root-mean-square velocity:

brainly.com/question/15995507

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1 year ago

Sometimes in lab we collect the gas formed by a chemical reaction over water (see sketch at right). This makes it easy to isolat

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Answer:

The correct answer is 0.12 grams.

Explanation:

The mass of carbon monoxide or CO collected in the tube can be determined by using the ideal gas equation, that is, PV = nRT.

Based on the given question, P or the pressure of the gas is given as 1 atm, volume of the gas collected in the tube is 117 ml or 0.117 L.

The number of moles or n can be determined by using the equation, mass/molar mass.

R is the universal gas constant, whose value is 0.0821 L atmK^-1mol^-1, and temperature is 55 degree C or 328 K (55+273).

On putting the values we get:

n = PV/RT

= (1 atm*0.117 L) / (0.0821 L atmK^-1mol^-1 * 328 K)

= 0.0043447 mol

Therefore, mass of CO will be moles * molar mass of CO

= 0.0043447 mol * 28 g/mol

= 0.12 g

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