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3 years ago

☝️☝️☝️help☝️☝️☝️!!!!

Chemistry

1 answer:

nataly862011 [7]3 years ago

7 0

8. A. Density is independent of size (an intensive property).
9. B. The highest density is 1786 g/20cm^3, or 89.3 g/cm^3. The least is 512 g/20cm^3, or 25.6 g/cm^3. Therefore, the difference is 89.3 - 25.6, or 63.7 g/cm^3.
10. C. A bottle filled with air weighs less than one filled with marshmallows, because air is less dense than marshmallows.
11. D. The number represents the number of protons in the nucleus of the atom, as well as the atomic number of the element.
12. C. The number represents the atomic mass of the element, which is determined based on the relative abundance of each form of the element.

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Use the Henderson-Hasselbalch equation, eq. (3), to calculate the pH expected for a buffer solution prepared from this acid and

notka56 [123]

Answer:

$pH=4.56$

Explanation:

Hello there!

In this case, given the Henderson-Hasselbach equation, it is possible for us to compute the pH by firstly computing the concentration of the acid and the conjugate base; for this purpose we assume that the volume of the total solution is 0.025 L and the molar mass of the sodium base is 234 - 1 + 23 = 256 g/mol as one H is replaced by the Na:

$n_{acid}=\frac{0.2g}{234g/mol}=0.000855mol\\\\n_{base}= \frac{0.2g}{256g/mol}=0.000781mol$

And the concentrations are:

$[acid]=0.000855mol/0.025L=0.0342M$

$[base]=0.000781mol/0.025L=0.0312M$

Then, considering that the Ka of this acid is 2.5x10⁻⁵, we obtain for the pH:

$pH=-log(2.5x10^{-5})+log(\frac{0.0312M}{0.0342M} )\\\\pH=4.60-0.04\\\\pH=4.56$

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2 years ago

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Explanation:

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