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nekit [7.7K]
3 years ago
12

Acetic acid is a weak acid with a pKa of 4.76. What is the concentration of acetate in a buffer solution of 0.2M at pH 4.9. Give

your answer in M but as a numeral only to 2 decimal places.
Chemistry
1 answer:
Ghella [55]3 years ago
6 0

Answer:

[base]=0.28M

Explanation:

Hello,

In this case, by using the Henderson-Hasselbach equation one can compute the concentration of acetate, which acts as the base, as shown below:

pH=pKa+log(\frac{[base]}{[acid]} )\\\\\frac{[base]}{[acid]}=10^{pH-pKa}\\\\\frac{[base]}{[acid]}=10^{4.9-4.76}\\\\\frac{[base]}{[acid]}=1.38\\\\

[base]=1.38[acid]=1.38*0.20M=0.28M

Regards.

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A solution is made by mixing equal masses of methanol, CH4O, and ethanol, C2H6O. Determine the mole fraction of each component t
Serggg [28]

Answer: mole fraction of methanol = 0.590

mole fraction of ethanol = 0.410

Explanation:

We are given:

Equal masses of methanol CH_4O and ethanol C_2H_6O are mixed.

let the mass be x g.

Calculating the moles of methanol in the solution, by using the equation:

\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}=\frac{xg}{32.04g/mol}

Calculating the moles of ethanol in the solution, by using the equation:

\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}=\frac{xg}{46.07g/mol}

To calculate the mole fraction of methanol, we use the equation:

\chi_{methanol}=\frac{n_{methanol}}{n_{methaol}+n_{ethanol}}

\chi_{methanol}=\frac{\frac{xg}{32.04g/mol}}{\frac{xg}{32.04g/mol}+\frac{xg}{46.07g/mol}}=0.590

To calculate the mole fraction of ethanol, we use the equation:

\chi_{ethanol}=\frac{n_{ethanol}}{n_{methaol}+n_{ethanol}}

\chi_{ethanol}=\frac{\frac{xg}{46.07g/mol}}{\frac{xg}{32.04g/mol}+\frac{xg}{46.07g/mol}}=0.410

Thus mole fraction of methanol is 0.590 and mole fraction of ethanol 0.410 in three significant figures.

5 0
3 years ago
A gas at constant temperature is enclosed in a container with a movable piston. It occupies a space of 10L at a pressure of 500
Liula [17]

Answer:

4.17L

Explanation:

V1 = 10L

V2 =?

P1 = 500torr

P2 = 1200torr

Boyle's law states that at constant temperature, the volume of a gas is inversely proportional to its pressure.

P1V1 = P2V2

V2 = ( P1 * V1 ) / P2

V2 = 4.17L

The new volume of the gas is 4.17L

8 0
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Explanation: Atomic mass of Be is 9.012 g/mol.

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4 0
3 years ago
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jekas [21]

Answer:

For each scenario as following:

A. 3 Potential deaths by chlorine exposure

B. 1 Potential deaths by chlorine exposure

C. 3 Potential deaths by chlorine exposure

Explanation:

According to Freitag, 1941 Chlorine exposure can be lethal at the concentration of 34-51 ppm in a time of 1h-1.5h. The answers are based on his reference.

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Answer:

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3 years ago
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